Labslink Research News

Making do with more: Joint BioEnergy Institute researchers engineer plant cell walls to boost sugar yields for biofuels

Fri, 29 Mar 2013 19:03:03 PDT

When blessed with a resource in overwhelming abundance it’s generally a good idea to make valuable use of that resource. Lignocellulosic biomass is the most abundant organic material on Earth. For thousands of years it has been used as animal feed, and for the past two centuries has been a staple of the paper industry. This abundant resource, however, could also supply the sugars needed to produce advanced biofuels that can supplement or replace fossil fuels.......> Full story

Bugs need symbiotic bacteria to exploit plant seeds

Wed, 09 Jan 2013 14:32:12 PDT

Aggregations of the red and black colored firebugs are ubiquitous under linden trees in Central Europe, where the bugs can reach astounding population densities. While these insects have no impact on humans, their African, Asian, and American relatives, the cotton stainers, are serious agricultural pests of cotton and other Malvaceous plants.......> Full story

Invading species can extinguish native plants despite recent reports

Wed, 09 Jan 2013 14:29:16 PDT

Ecologists at the University of Toronto and the Swiss Federal Institute of Technology Zurich (ETH Zurich) have found that, given time, invading exotic plants will likely eliminate native plants growing in the wild despite recent reports to the contrary........> Full story

Increasing drought stress challenges vulnerable hydraulic system of plants, GW professor finds

Tue, 27 Nov 2012 14:41:59 PDT

The hydraulic system of trees is so finely-tuned that predicted increases in drought due to climate change may lead to catastrophic failure in many species. A recent paper co-authored by George Washington University Assistant Professor of Biological Sciences Amy Zanne finds that those systems in plants around the globe are operating at the top of their safety threshold, making forest ecosystems vulnerable to increasing environmental stress........> Full story

Algae can draw energy from other plants

Tue, 20 Nov 2012 16:33:28 PDT

Until now, it was believed that only worms, bacteria, and fungi could digest vegetable cellulose and use it as a source of carbon for their growth and survival. Plants, in contrast, engage in the photosynthesis of carbon dioxide, water, and light. In a series of experiments, Professor Dr. Olaf Kruse and his team cultivated the microscopically small green alga species Chlamydomonas........> Full story

Native plant fares well in pilot green roof research study

Mon, 15 Oct 2012 16:25:16 PDT

As the implementation of green roofs increase, a University of Cincinnati pilot study examined which plants best thrive on the region’s roofs during the dry, hot conditions of summer.......> Full story

Scientists urge new approaches to plant research

Fri, 29 Jun 2012 17:02:31 PDT

In a paper published this week in the journal Science, a Michigan State University professor and a colleague discuss why if humans are to survive as a species, we must turn more to plants for any number of valuable lessons........> Full story

Indigenous peoples at forefront of climate change offer lessons on plant biodiversity

Mon, 27 Feb 2012 16:58:53 PDT

Humans are frequently blamed for deforestation and the destruction of environments, yet there are also examples of peoples and cultures around the world that have learned to manage and conserve the precious resources around them. The Yanesha of the upper Peruvian Amazon and the Tibetans of the Himalayas are two groups of indigenous peoples carrying on traditional ways of life........> Full story

Hermetic bags save African crop, but not how experts once thought

Wed, 22 Feb 2012 19:30:18 PDT

The hermetic grain storage bags that cut off oxygen to weevils and have saved West and Central African farmers hundreds of millions of dollars by putting the brakes on the insects' rapid multiplication don't merely suffocate them as once thought, a Purdue University study shows.......> Full story

Revealed in accurate detail, the underground world of plants

Fri, 17 Feb 2012 15:27:07 PDT

Plant and computer scientists can now study the underground world of plants with more accuracy and clarity. The revolutionary technique will improve our chances of breeding better crop varieties and increasing yields.......> Full story

UF research on newly formed plants could lead to improved crop fertility

Fri, 06 Jan 2012 17:08:23 PDT

A new University of Florida study shows genomes of a recently formed plant species to be highly unstable, a phenomenon that may have far-reaching evolutionary consequences........> Full story

Acid rain poses a previously unrecognized threat to Great Lakes sugar maples

Thu, 15 Dec 2011 18:23:21 PDT

The number of sugar maples in Upper Great Lakes forests is likely to decline in coming decades, according to University of Michigan ecologists and their colleagues, due to a previously unrecognized threat from a familiar enemy: acid rain........> Full story

Report: Herbicide atrazine spurs reproductive problems in many creatures

Mon, 28 Nov 2011 17:19:33 PDT

An international team of researchers has reviewed the evidence linking exposure to atrazine – an herbicide widely used in the U.S. and more than 60 other nations – to reproductive problems in animals. The team found consistent patterns of reproductive dysfunction in amphibians, fish, reptiles and mammals exposed to the chemical.......> Full story

Bat plant could give some cancers a devil of a time

Tue, 22 Nov 2011 17:07:03 PDT

In a new study published this month in the Journal of the American Chemical Society, researchers with The University of Texas Health Science Center at San Antonio have pinpointed the cancer-fighting potential in the bat plant, or Tacca chantrieri........> Full story

Plant with 'eggbeater' testure inspires waterproof coating

Thu, 10 Nov 2011 17:17:06 PDT

A floating weed that clogs waterways around the world has at least one redeeming feature: It’s inspired a high-tech waterproof coating intended for boats and submarines.......> Full story

Genome-scale network of rice genes to speed the development of biofuel crops

Wed, 02 Nov 2011 16:40:17 PDT

The first genome-scale model for predicting the functions of genes and gene networks in a grass species has been developed by an international team of researches that includes scientists with the U.S. Department of Energy (DOE)’s Joint BioEnergy Institute (JBEI), a multi-institutional partnership led by Lawrence Berkeley National Laboratory (Berkeley Lab). Called RiceNet, this systems-level model of rice gene interactions should help speed the development of new crops for the production of advanced biofuels, as well as help boost the production and improve the quality of one of the world’s most important food staples........> Full story

Protein plays role in helping plants see light

Wed, 12 Oct 2011 17:51:20 PDT

Plants do not have eyes or legs, yet they are able to "see" and move toward and away from light. This ability, called phototropism, is controlled by a series of molecular-level signals between proteins inside and between plant cells. In a paper published in The Plant Cell, University of Missouri scientists report for the first time the elusive role a critical protein plays in this molecular signaling pathway that regulates phototropism in plants. Directional light that induces phototropism is sensed by a plant through the action of two light-sensing proteins, phototropin 1 and phototropin 2. These proteins act as photoreceptors and initiate the phototropic signaling response in conjunction with a third protein, called NPH3. "If the phototropic signaling pathway were like a baseball game, the phototropins would be the pitcher and NPH3 the catcher who work together to coordinate the signal, or pitch," says Mannie Liscum, a professor of biological sciences in the College of Arts and Science and in the Christopher S. Bond Life Sciences Center. "Prior to this study, no one knew how NPH3 and the phototropins cooperated to facilitate the signal." Using a combination of genetic and biochemical methods, Liscum and colleagues found that NPH3 functions as part of a protein complex that modifies phototropin 1 by the addition of a small protein "tag" called ubiquitin. Either a single ubiquitin or a chain of ubiquitin proteins is added, depending on the amount of light the plant "sees." If we continue the baseball analogy, ubiquitin is the hand signals NPH3 uses to coordinate with phototropin 1 the type and sequence of signals depending on the particular lighting situation. "In low-light conditions, phototropin 1 is modified with single ubiquitin proteins and then apparently moves to a different part of the cell. In high-light conditions, phototropin 1 is modified with multiple ubiquitin proteins and is degraded by the cell to shut down further signaling," says Liscum. The finding may have applicability to research beyond phototropism in plants. "The tagging of proteins with ubiquitin represents a common biochemical event throughout the biological world. In fact, many human disease pathologies are associated with alterations in ubiquitin-tagging," says Liscum. "Our studies identifying a single enzyme complex that is capable of modifying a substrate in different ways simply based on the environmental conditions may therefore have implications on fields far askew from agriculture."

New study shows how trees clean the air in London

Wed, 05 Oct 2011 17:22:03 PDT

New research by scientists at the University of Southampton has shown how London's trees can improve air quality by filtering out pollution particulates, which are damaging to human health. A paper published this month in the journal Landscape and Urban Planning indicates that the urban trees of the Greater London Authority (GLA) area remove somewhere between 850 and 2000 tonnes of particulate pollution (PM10) from the air every year. An important development in this research, carried out by Dr Matthew Tallis, is that the methodology allows the prediction of how much pollution will be removed in the future as the climate and pollution emissions change. This shows the real benefits of the planned increase in the number of street trees in London and throughout England, including the GLA's plan to increase the area of urban trees by 2050 and the current government's 'Big tree plant' initiative. The research found that the targeting of tree planting in the most polluted areas of the GLA area and particularly the use of a mixture of trees, including evergreens such as pines and evergreen oak, would have the greatest benefit to future air quality in terms of PM10 removal. One of the paper's authors Professor Gail Taylor explains: "Trees have evolved to remove CO₂ from the atmosphere, so it's not surprising that they are also good at removing pollutants. Trees which have leaves the whole year are exposed to more pollution and so they take up more. Using a number of different tree species and modelling approaches, the effectiveness of the tree canopy for clean air can be optimised." This study presents predictions of particulate (PM10) uptake in future climate and for five tree planting scenarios in London. Using seasonal rather than hourly data was shown to have little impact on modelled annual deposition of pollution (PM10) to urban canopies, suggesting that pollution uptake can be estimated in other cities and for the future where hourly data are not available. Co-author Peter Freer-Smith, Chief Scientist for Forest Research (Forestry Commission) and visiting professor at the University of Southampton, says: "We know that particulates can damage human health, for example exacerbating asthma and this reduction in exposure could have real benefits in some places, such as around the edge of school playgrounds. Urban greenspace and trees give a wide range of benefits and this study confirms that improving air quality is one of them and will also help us to get the most out of this benefit in future."

St. Michael's studies Toronto community services

Fri, 23 Sep 2011 17:02:58 PDT

Torontonians want non-profit organizations to provide programs and services in their neighbourhoods that are relevant to their needs, held at convenient times and locations and have stable funding, a research study has found. People under 25 and without post-secondary education also want these organizations to help them find jobs and become financially stable, the study found. The study was conducted between December and July by St. Michael's Hospital's Centre for Research on Inner City Health (CRICH). Researchers asked Torontonians what they thought the city should pay attention to when it comes to community services in their neighbourhoods, ranging from boys and girls clubs to community gardens, drop in programs for seniors, or mentorship and job skills programs for newcomers and youths. Patricia O'Campo, one of the authors of the study and the director of CRICH, said the results were particularly significant because the people surveyed were asked open-ended questions about what was important to them and what the city should pay attention to. Respondents provided their own answers rather than choosing from a list of options selected by the surveyors. O'Campo, an epidemiologist, said the results were also important because they were consistent across all neighbourhoods of the city and ethnic and demographic groups. "Torontonians don't want to have to leave their neighbourhoods to get the programs they need," O'Campo said. "They want programs to be available and accessible. They also want community organizations to have stable funding, so services aren't interrupted because they run out of money." The results come as Toronto City Council debates possibly wide-ranging service and program cuts in an effort to eliminate a budget deficit.

Firewood movement leading cause of oak infestation in San Diego County

Fri, 02 Sep 2011 18:49:38 PDT

A catastrophic infestation of the goldspotted oak borer, which has killed more than 80,000 oak trees in San Diego County in the last decade, might be contained by controlling the movement of oak firewood from that region, according to researchers at the University of California, Riverside........> Full story

New component of a plant steroid-activated pathway discovered

Thu, 18 Aug 2011 16:28:40 PDT

Plant biologists have been working for years to nail down the series of chemical signals that one class of plant hormones, called brassinosteroids, send from a protein on the surface of a plant cell to the cell's nucleus. New research from Carnegie scientists Tae-Wuk Kim and Zhiyong Wang, with contributions from the University of California San Francisco, isolated another link in this chain. Fully understanding the brassinosteroid pathway could help scientists better understand plant growth and help improve food and energy crop production. Brassinosteroids are found throughout the plant kingdom and regulate many aspects of growth and development, as well as resistance to external stresses. Mutant plants that are deficient in brassinosteroids show defects at many phases of the plant life cycle including reduced seed germination, irregular growth in the absence of light, dwarfism, and sterility. The series of proteins involved in a plant cell detecting the presence of brassinosteroids and using this information to respond to the plant's environment is one of the best-studied aspects of plant cellular physiology and biochemistry. Previous research had identified a pathway of chemical signals that starts when a brassinosteroid binds to a receptor on the surface of a plant cell and activates a cascade of activity that consists of adding and removing phosphates from a series of proteins. The research team was able to identify a new aspect of this pathway, a protein called Constitutive Differential Growth1, or CDG1. Their work will be published in Molecular Cell on August 19. Using an extensive array of research techniques, they determined that when activated by the brassinosteroid receptor, CDG1 adds a phosphate to another protein called BSU1. It was already known that the BSU1 protein in turns deactivates a third protein called BIN2. When BIN2 is active it inhibits two other proteins called BZR1 and BZR2, which are part of a special class called transcription factors. When they are inactive, they are unable to enter the plant cell's nucleus. But once BIN2 is deactivated by BSU1, they are able to bind directly to DNA molecules inside the nucleus and promote a wide variety of gene activity. "Together with our previous work, these results provide the detailed mechanisms of brassinosteroid signaling," Wang said. "Because this system of brassinosteroid-activated proteins is one of the best-understood chemical pathways in plant physiology, these results could help scientists understand many other plant cell systems."

Biologists discover an 'evening' protein complex that regulates plant growth

Wed, 13 Jul 2011 17:34:39 PDT

Farmers and other astute observers of nature have long known that crops like corn and sorghum grow taller at night. But the biochemical mechanisms that control this nightly stem elongation, common to most plants, have been something of a mystery to biologists—until now. In this week's early online publication of the journal Nature, biologists at the University of California, San Diego report their discovery of a protein complex they call the "evening complex" that regulates the rhythmic growth of plants during the night. More importantly, the biologists show how this protein complex is intricately coordinated through the biological clock with the genes that promote stem elongation in a way that could enable plant breeders to engineer new varieties of crops that grow faster, produce greater yields of food or generate more biomass per acre of land for conversion into biofuels. "This discovery gives us a molecular understanding of how the biological clock is regulating cyclic growth in plants," said Steve Kay, dean of UC San Diego's Division of Biological Sciences, who headed the research effort. "And it instantly gives us a handle on how we might manipulate and control plant yield or biomass deposition." While most people assume that plants grow at a slow and steady rate throughout the day and night, Charles Darwin and others more than a century ago observed that they actually grow in spurts late at night, with plant stems elongating fastest in the hours just before dawn. "Plants actually grow rhythmically," said Kay. "Some plants, like sorghum, have the ability to elongate a centimeter or more each night." The UCSD biologists initially focused their attention on three genes from a tiny mustard plant called Arabidopsis, which is used by geneticists as a laboratory model for plants. When they are disabled by mutations, these three genes disrupt the plant's biological clock and promote both stem elongation and early flowering. "These three genes have been of intense interest because the loss of function in each one of them kills the biological clock, causes a long hypocotyl, or juvenile stem, and tends to cause early flowering," said Kay. "We thought that maybe their function was related. So this investigation was basically started to figure out what these three genes do." The answer to that seemingly simple question took the biologists more than six years to disentangle. Their efforts were led by three postdoctoral fellows in Kay's lab: Dmitri Nusinow, Anne Helfer and Elizabeth Hamilton. "Circadian clocks control the timing of an extraordinary variety of developmental and physiological processes in humans and other species, but figuring out how they do this is tough," said Laurie Tompkins, who oversees biological clock grants at the National Institutes of Health's National Institute of General Medical Sciences, which funded the research. "Arabidopsis is ideal for this sort of analysis, since researchers can use a variety of sophisticated genetic and biochemical tools to study molecular interactions at different times of day and then easily observe the tiny plant's development." Because the three genes—Early Flowering3 (or ELF3), ELF4 and LUX—have biological activities that peak in the early evening, the UCSD biologists wondered if the three genes acted together in a protein complex. Through a series of experiments in yeast cells, they determined the three genes produced proteins that did interact with one another, but in a specific way. ELF3 served as a docking protein that brought together ELF4 and LUX, but the latter two did not interact with each other without ELF3's help. This protein complex was dubbed the "evening complex" by the UCSD scientists, who verified in Arabidopsis that not only did the biological activities of the three components of this protein complex peak in the evening, but so did the formation of the evening complex itself. The researchers then sought to answer the question of what the physiological role of this protein complex could be in plants. One main clue pointed them in the right direction: When any one of the three genes controlling this protein complex is disabled, plants end up with grossly elongated stems. "This protein complex is clearly acting like the brakes on growth," said Kay. "So when we mutate any one of these genes the plants elongate much more." In another set of experiments, the researchers demonstrated that the evening complex puts the brakes on the activity of two genes in plants—PIF4 and PIF5—that are important in promoting plant growth. "What we show in our paper is that the evening complex binds to the promoters of PIF4 and PIF5 and, at the end of the day and through the early part of the night, prevents the plants from growing," said Kay. "And when the levels of the evening complex begin to drop, PIF4 and PIF5 are expressed and drive plant expression programs that support stem elongation, and the brakes on plant growth are taken off." In this new model of plant growth developed by the scientists, PIF4 and PIF5 control the gas pedal that activates plants to grow, while the three genes that produce the evening complex act as the brakes and work with the plant's biological clock to permit the most rapid growth in the late evening and early morning hours. "Nobody knew how this cyclic regulation of plant growth worked on a molecular level, but this must be one of the major mechanisms," said Kay. "This really gives us a molecular understanding of how the biological clock is regulating cyclic growth in plants." Why plants time their diurnal cycle to grow most rapidly late at night and in the wee hours of the morning is still a mystery, but Kay suspects it could be when resources are most available since plants store what they produce from photosynthesis during the day as starch, then break that starch and protein down at night to make them available for growth. "Plants have to coordinate their growth with the availability of resources," he said. "There's really no advantage for these plants just to get bigger and bigger if they're not coordinating their metabolic resources, which come cyclically with photosynthesis each day. So plants grow rhythmically presumably to coordinate growth with available metabolic resources." As scientists gain a better understanding of these plant growth control mechanisms, the potential commercial applications to agriculture could be as broad as they are significant. The discovery of the mechanisms of the evening complex should eventually provide plant geneticists with a new way to optimize the growth of crops so they can produce more food or more biomass per acre for biofuel production. "What this discovery tells us is that the circadian clock is controlling tens of millions of tons of biomass deposition every night in the United States that could be used for bioenergy," said Kay. "Now that we understand what the gas and the brakes are in controlling plant growth, we can manipulate those to maximize biomass deposition. We could do it by putting the gas on more or putting the brakes on less or probably in a more sophisticated way by combining the gas and brakes so that we allow the plant to maximize available nutrients, which will allow it to maximize biomass deposition. This could be a way to optimize plant growth for a particular environment where we don't want to add additional nutrients to the soil." Kay said another totally unrelated application for the evening complex could be in making plants, particularly food crops, more tolerant to cold temperatures or freezing. "When you make mutations to these genes, the plants are less tolerant to freezing and low temperatures," he said. "So we think the evening complex is likely to have a role in cold tolerance and that's something else we're going to be investigating."

Simple little spud helps scientists crack potato's mighty genome

Mon, 11 Jul 2011 17:44:38 PDT

The Potato Genome Sequencing Consortium (PGSC), a team of scientists from institutions worldwide, including Virginia Tech, has published its findings in the Sunday July 10 online issue of the journal Nature. The successful sequencing of the genome of the world's third most important crop began when Richard Veilleux, who is the Julian and Margaret Gary Professor of Horticulture in the College of Agriculture and Life Sciences at Virginia Tech, wondered if the then new applications of plant tissue culture could be used to develop parent lines for hybrid potatoes. The concept was developed from his doctoral research, completed in 1981 at the University of Minnesota. Most modern crop varieties are hybrids because hybrids are usually more vigorous than either parent. For example, with corn, a variety with desirable characteristics is self-pollinated for many generations, and the resulting seed is grown and crossbred with another similarly developed line with a different genetic background. Since potatoes do not self-pollinate, Veilleux engineered inbred lines from immature pollen extracted from flower buds by using plant tissue culture. The result, potato plants with half the chromosomes of the parent, was completely sterile. "Their chromosomes have to be doubled, up to 24, which results in plants with completely identical pairs of chromosomes – a homozygous inbred line," said Veilleux. "In one cycle, you have accomplished what it takes five generations to do to create a maize inbred line the old-fashioned way." Since that initial success, he has conducted years of basic research to improve these lines as building blocks for hybrid potato seed, supported by the U.S. Department of Agriculture through Hatch grants, among other funding. Over the years, he reported at international meetings on his progress toward developing a vigorous homozygous inbred line with desirable traits for hybrid parenthood. By 2006, when an international team formed the Potato Genome Sequencing Consortium to attempt to sequence the genome of the potato, Veilleux's simple little spuds were poised for fame as the first potato to have its genome sequenced. But first, the consortium, made up of groups at institutions from 14 countries, wanted to sequence a more popular and productive tuber, more resembling what is found on dinner tables worldwide. The consortium was working with a diploid variety that, like Veilleux's potato, has only 24 chromosomes. However, the pairs of chromosomes of the selected line are not identical; they carry variations of similar genes, resulting in thousands of differences in the base pairs – or rungs on the DNA ladder-- between chromosome pairs. Modern sequencing technology is a time saver, spitting out 50-base pair sequences millions at a time. But the well-regarded modern potato has 840 million base pairs. The variation between pairs of chromosomes essentially doubled that. Assembling the puzzle was becoming overwhelming. Then scientists within the consortium remembered Veilleux's presentations at international meetings about a simple little potato he was developing with hopes of it someday parenting a new hybrid. Sanwen Huang with the Chinese Academy of Agricultural Science, and Robin Buell of Michigan State University, both members of the consortium steering committee, each approached Veilleux for permission to use his simpler homozygous diploid potatoes for sequencing. "I said, 'sure', and was invited to become a member of the consortium," said Veilleux. Veilleux sent his plant material directly to Buell, whereas Huang obtained DNA of the same potato from Peru, where Veilleux had sent cultures years before for breeding studies by Meredith Bonierbale of the International Potato Center (CIP). DNA tests were done to make sure that the potatoes Buell and Huang obtained were the same – which they were. According to the consortium news release, "Analysis of the genome sequence data has revealed that the potato genome contains approximately 39,000 protein coding genes. For over 90 percent of the genes the location on one of the 12 chromosomes is now known. The analysis also reveals that the potato genome has undergone extensive genome duplication through evolution… The data also show clear evidence for how expansion of particular gene families has contributed to the evolution of the potato tuber – the edible storage organ that is the most striking feature of this important and fascinating plant. " "We can thank many Hokies, who have been paid as undergraduate hourly employees for decades on the project to maintain the potato collection in tissue culture," said Veilleux. "Research specialist Suzanne Piovano trained them to conduct routine subcultures to fresh medium every few weeks and to keep the confusing potato identities straight. The many potato crops required for the project have been grown under the vigilance of the horticulture department's capable greenhouse manager, Jeff Burr." Veilleux's original potatoes actually came from South America – a diploid species called phureja that produces potatoes of many colors, textures, and tastes. Now, the sequence of Veilleux's little potato will be used as a draft against which the genome sequences of more complicated tubers will be compared. "Sequencing technology is getting better, and now that we have sequenced this one potato, it is kind of easy," he said. "There are all kinds of spinoff studies that can be done, such as looking at the DNA sequence variation in the genomes of different kinds of potatoes. "These sequences will allow scientists to locate genes for desired traits and develop new varieties. All potatoes have essentially the same genes but the forms of the genes vary so that similar genes found in Idaho Russets or Red Norlands on the supermarket shelves can be compared to those in the sequenced line to determine how differences in the genetic code affect traits that make up the quality of commercial potatoes," Velleux said. What about using inbred lines to produce hybrid varieties? That may never happen, but Veilleux said he will keep trying. Just this spring, students in his graduate class in advanced plant genetics were working in Virginia Tech's greenhouses, crossing commercial varieties and hybrids from his inbred lines. Maybe the next crop of hybrids will find their way onto tables eventually. The project is also resulting in new collaborations. "Dr. Huang wants to work with me to find out what genetic material was left behind in the process of creating the inbred lines," said Veilleux.

What is good for you is bad for infectious bacteria

Fri, 04 Mar 2011 03:21:05 PDT

Plants are able to protect themselves from most bacteria, but some bacteria are able to breach their defences. In research to be published in Science on Friday, scientists have identified the genes used by some strains of the bacterium Pseudomonas to overwhelm defensive natural products produced by plants of the mustard family, or crucifers. "Microbes only become pathogens when they find a way to infect a host and overwhelm the host defences," said lead author Dr Jun Fan from the John Innes Centre on the Norwich Research Park. "Our findings answer some important questions about host-pathogen biology." The scientists have confirmed that the chemicals used by cruciferous plants to defend against bacteria are isothiocyanates, nitrogen and sulphur-containing organic compounds produced by plants of the mustard family, such as cabbage, broccoli and Brussels sprouts. These potent molecules have antioxidant, anticancer and anti-inflammatory properties in humans. Isothiocyanates are released by the plant when it is challenged or eaten. They had previously been shown to be active against bacteria but this is the first time their essential role has been successfully tested using real plants. Without this class of compounds, crucifers would be more vulnerable to disease from a much wider variety of bacteria. Isothiocyanates also provide a chemical barrier to harmful fungi and a toxic defence warning to insects and other herbivores. The team of scientists from JIC and the University of Edinburgh found that bacterial pathogens carrying the sax genes, thought to be involved in detoxification and removal of isothiocyanates, were able to overcome these defences. Understanding how some bacterial strains become specialised to overcome plant resistance will help scientists identify new ways to improve crop plants. "These discoveries have a broader significance for current efforts to increase food security," said co-author Dr Peter Doerner from Edinburgh University. "They define a strategy for sustainable disease control in agriculture by stimulating the production and variety of natural products in various crop plants." The research was initiated by former JIC director Professor Chris Lamb and he is an author on the paper. "Chris supported the research for over a decade up until his death in 2009," said Dr Fan. "This is a good example of his pursuit of excellence and relevance in scientific research."

Texas leafcutter ants aided, but also limited, by cold-tolerant fungus crops, research shows

Wed, 23 Feb 2011 03:17:38 PDT

Texas leafcutter ants farm crops of fungus that evolved cold tolerance to Texas winters, just as northern farmers cultivate cold weather crops, researchers from The University of Texas at Austin show in a new paper published in the journal PNAS Early Edition. Though the cold tolerant fungus gives the ants the ability to maintain winter gardens, the fungus is still sensitive enough to cold it limits the ant's ability to spread farther northward. "The same is true for human farmers," says Ulrich Mueller, professor of biology. "Some of our crops come originally from the tropics, and humans have had to select them over time to grow in colder climates. But we are still limited by our abilities to select and adapt crops to local conditions." Mueller and his colleagues found that even within Texas the fungus is more tolerant of cold at its northern edge near Dallas, and less tolerant of cold at its southern edge near Brownsville. At Fort Belknap, just northwest of Dallas, Mueller says the ants "are just hanging on." Leafcutter ants are largely tropical, and the Texas leafcutter ant, Atta texana, is one of only three leafcutter ant species found in the United States. The species arrived in the region about 10,000 years ago after the retreat of the glaciers and the end of the last Ice Age. "The ants may have only been in Fort Belknap for a few hundreds or thousands of years," Mueller says. The ant's symbiotic relationship with the cold tolerant fungus clearly permits it to survive in the more temperate environments of Texas. The finding provides a perspective on symbiotic relationships, which are normally thought of as being beneficial to both organisms. "We normally think that forging a symbiotic relationship enriches lives—that each organism is helping the other," says Mueller. "But we have found that this can be the opposite. In the tropics, the symbiosis between the leafcutter ants and their fungal crops helped to broaden the ants' ecological niches. In the Texas leafcutter, the symbiotic relationship also constrains them." Texas is a particularly interesting laboratory for studies of local species adaptations because of its unique ecological conditions. It is the only state in the U.S. where an unusually steep precipitation gradient from east to west crosses a steep temperature gradient from north to south, ranging from temperate to subtropical. "Texans are uniquely positioned to monitor the effect of environmental change on U.S. biodiversity," says Mueller. "It will be interesting to see what happens with these ants over the next 10 to 20 years with global warming. Will they expand to Oklahoma and across the Mississippi River, or will cold snaps like those we just experienced knock them back?"

Plant breeding is being transformed by advances in genomics and computing

Mon, 21 Feb 2011 03:30:14 PDT

The arrival of affordable, high throughput DNA sequencing, coupled with improved bioinformatics and statistical analyses is bringing about major advances in the field of molecular plant breeding. Multidisciplinary breeding programs on the world's major crop plants are able to investigate genome-wide variations in DNA sequences and link them to the inheritance of highly complex traits controlled by many genes, such as hybrid vigor. Furthermore, there has been a step-change in speed and cost-effectiveness. What previously took six generations to achieve can now be done in two, delivering massive time and resource savings. This has made molecular plant breeding feasible on marginal crops including medicinal plants and crops of the developing world. Agriculture faces demands to sustainably produce enough food for an expanding world population and to improve the nutritional quality of food crops, as well as to provide non-food crops, e.g. for the biofuels industry. The progress in molecular plant breeding can help meet these demands by;

shortening the time it takes to domesticate new crops from semi-wild plants,
tailoring existing crops to meet new requirements, such as nutritional enhancement or climate change,
rapidly incorporating valuable traits from wild relatives into established crops,
allowing plant breeders to work with highly complex traits, such as hybrid vigour and flowering,
making it feasible to work on research-neglected "orphan" crops.

Plants that can move inspire new adaptive structures

Mon, 21 Feb 2011 03:28:53 PDT

The Mimosa plant, which folds its leaves when they're touched, is inspiring a new class of adaptive structures designed to twist, bend, stiffen and even heal themselves. University of Michigan researchers are leading their development. Mechanical engineering professor Kon-Well Wang will present the team's latest work Feb. 19 at the American Association for the Advancement of Science's 2011 Annual Meeting in Washington D.C. He will also speak at a news briefing earlier that day. Wang is the Stephan P. Timoshenko Collegiate Professor of Mechanical Engineering and chair of the Department of Mechanical Engineering. "This is quite different from other traditional adaptive materials approaches," Wang said. "In general, people use solid-state materials to make adaptive structures. This is really a unique concept inspired by biology." Researchers at U-M and Penn State University are studying how plants like the Mimosa can change shape, and they're working to replicate the mechanisms in artificial cells. Today, their artificial cells are palm-size and larger. But they're trying to shrink them by building them with microstructures and nanofibers. They're also exploring how to replicate the mechanisms by which plants heal themselves. "We want to put it all together to create hyper-cellular structures with circulatory networks," Wang said. The Mimosa is among the plant varieties that exhibit specialized "nastic motions," large movements you can see in real time with the naked eye, said Erik Nielsen, assistant professor in the U-M Department of Molecular, Cellular and Developmental Biology. The phenomenon is made possible by osmosis, the flow of water in and out of plants' cells. Triggers such as touch cause water to leave certain plant cells, collapsing them. Water enters other cells, expanding them. These microscopic shifts allow the plants to move and change shape on a larger scale. It's hydraulics, the researchers say. "We know that plants can deform with large actuation through this pumping action," Wang said. "This and several other characteristics of plant cells and cell walls have inspired us to initiate ideas that could concurrently realize many of the features that we want to achieve for adaptive structures." Nielsen believes nastic movements might be a good place to start trying to replicate plant motions because they don't require new growth or a reorganization of cells. "These rapid, nastic motions are based on cells and tissues that are already there," Nielsen said. "It's easy for a plant to build new cells and tissues during growth, but it's not as easy to engineer an object or machine to completely change the way it's organized. We hope studying these motions can inform us about how to make efficient adaptive materials that display some of the same types of flexibility that we see in biological systems." When this technology matures, Wang said it could enable robots that change shape like elephant trunks or snakes to maneuver under a bridge or through a tunnel, but then turn rigid to grab a hold of something. It also could lead to morphing wings that would allow airplanes to behave more like birds, changing their wing shape and stiffness in response to their environment or the task at hand.

Plants cloned as seeds

Fri, 18 Feb 2011 03:21:11 PDT

Plants have for the first time been cloned as seeds. The research by aUC Davis plant scientists and their international collaborators, published Feb. 18 in the journal Science, is a major step towards making hybrid crop plants that can retain favorable traits from generation to generation. Most successful crop varieties are hybrids, said Simon Chan, assistant professor of plant biology at UC Davis and an author of the paper. But when hybrids go through sexual reproduction, their traits, such as fruit size or frost resistance, get scrambled and may be lost. "We're trying to make a hybrid that breeds true," Chan said, so that plants grown from the seed would be genetically identical to one parent. Some plants, especially fruit trees, can be cloned from cuttings, but this approach is impractical for most crops. Other plants, especially weeds such as hawkweed and dandelions, can produce true seeds that are clones of themselves without sexual reproduction -- a still poorly understood process called apomixis. The new discovery gets to the same result as apomixis, although by a different route, Chan said. Normally, eggs and sperm are haploid -- they have half the number of chromosomes of the parent. The fertilized egg and the adult plant it grows into are diploid -- containing a full complement of chromosomes, half contributed by each parent. Chan and his colleagues focused their work on the laboratory plant Arabidopsis, which has certain genetic mutations that allow it to produce diploid eggs without sexual recombination. These eggs have the same genes and number of chromosomes as their parents. But those eggs cannot be grown into adult plants without fertilization by sperm, which adds another parent's set of chromosomes. Last year, Chan and UC Davis postdoctoral researcher Maruthachalam Ravi showed that they could breed haploid Arabidopsis plants that carried chromosomes from only one parent. They introduced a genetic change so that after the eggs were fertilized, the chromosomes from one of the parents were eliminated. Such haploid plants would reduce the time needed to breed new varieties. In the new study, Chan's lab, with colleagues from India and France, crossed these Arabidopsis plants programmed to eliminate a parent's genes with either of two mutants that can produce diploid eggs. The result? In about one-third of the seeds produced, the diploid eggs were successfully fertilized, then the chromosomes from one parent were eliminated, leaving a diploid seed that was a clone of one of its parents. Ravi described the result as a step on the way towards artificial apomixis. The team hopes to produce crop plants, such as lettuce and tomato, that can fertilize themselves and produce clonal seeds. Applications for provisional patents on the work have been filed.

The production of plant pollen is regulated by several signaling pathways

Thu, 27 Jan 2011 03:21:40 PDT

Flowers are no ornamental luxury to plants; after all, they hold the male and female reproductive organs. The male pollen is produced in the stamens and the carpel bears the female ovule. The fusion of the two produces a germinable embryo that ensures the reproduction of the plant. Plants can only bloom if a radical transition occurs during their development. This stops the production of leaves and instead causes the reproductive cells that are equipped with a single set of chromosomes to form sexually distinctive reproductive organs. For optimal reproduction, this must coincide with certain external conditions, such as light and temperature. However, sensitivity to the external conditions must not be so great that it prevents blooming if the environmental conditions are not optimal.......> Full story

Nailing down a crucial plant signaling system

Mon, 24 Jan 2011 03:23:51 PDT

Plant biologists have discovered the last major element of the series of chemical signals that one class of plant hormones, called brassinosteroids, send from a protein on the surface of a plant cell to the cell's nucleus. Although many steps of the pathway were already known, new research from a team including Carnegie's Ying Sun and Zhiyong Wang fills in a missing gap about the mechanism through which brassinosteroids cause plant genes to be expressed. Their research, which will be published online by Nature Cell Biology on January 23, has implications for agricultural science and, potentially, evolutionary research. "Brassinosteroids are found throughout the plant kingdom and regulate many aspects of growth and development, as well as resistance from external stresses," said Wang. "Mutant plants that are deficient in brassinosteroids show defects at many phases of the plant life cycle, including reduced seed germination, irregular growth in the absence of light, dwarfism, and sterility." Previous research had identified a pathway of chemical signals that starts when a brassinosteroid binds to a receptor on the surface of a plant cell and activates a cascade of activity that consists of adding and removing phosphates from a series of proteins. When brassinosteroids are not present, a protein in this pathway called BIN2 acts to add phosphates to two other proteins called BZR1 and BZR2, which are part of a special class of proteins called transcription factors. The phosphates inhibit the transcription factors. But when a brassinosteroid binds to the cell-surface receptor, BIN2 is deactivated, and as a result phosphates are removed from the two transcription factors. As a result, BZR1 and BZR2 can enter the cell's nucleus, where they bind directly to DNA molecules and promote a wide variety of gene activity. Before this new research, the protein that detaches the phosphates and allows BZR1 and BZR2 to work was unknown. Using an extensive array of research techniques, the team was able to prove that a protein called protein phosphatase 2A (PP2A) is responsible. "We discovered that PP2A is a key component of the brassinosteroid signaling pathway," Wang said. "This discovery completes the core signaling module that relays extracellular brassinosteroids to cue activity in the nucleus." Further research is needed to determine whether brassinosteroid binding activates PP2A, or just deactivates BIN2, thus allowing PP2A to do this job. Additionally, PP2A is involved in a plant's response to gravity and light, among other things. This aspect of the brassinosteroid signaling pathway bears some surprising resemblances to signaling pathways found in many members of the animal kingdom. More research could demonstrate details of the evolutionary split between non-protozoan animals and plants.

Grape ingredient resveratrol increases beneficial fat hormone

Sat, 08 Jan 2011 17:34:56 PDT

Resveratrol, a compound in grapes, displays antioxidant and other positive properties. In a study published this week, researchers at the UT Health Science Center San Antonio describe a novel way in which resveratrol exerts these beneficial health effects.

Resveratrol stimulates the expression of adiponectin, a hormone derived from cells that manufacture and store fat, the team found. Adiponectin has a wide range of beneficial effects on obesity-related medical complications, said senior author Feng Liu, Ph.D., professor of pharmacology and member of the Barshop Institute of Longevity and Aging Studies at the Health Science Center.

Both adiponectin and resveratrol display anti-obesity, anti-insulin resistance and anti-aging properties.......> Full story

University of Illinois research makes plant breeding easier

Wed, 05 Jan 2011 03:48:00 PDT

University of Illinois research has resulted in the development of a novel and widely applicable molecular tool that can serve as a road map for making plant breeding easier to understand. Researchers developed a unified nomenclature for male fertility restorer (RF) proteins in higher plants that can make rapid advancements in plant breeding. "Understanding the mechanism by which RF genes suppress the male sterile phenotype and restore fertility to plants is critical for continued improvements in hybrid technology," said Manfredo J. Seufferheld, U of I assistant professor of crop sciences. To reach this goal, Seufferheld teamed up with post-doctoral researchers Simeon O. Kotchoni and Emma W. Gachomo of Purdue University, and Jose C. Jimenez-Lopez of the Estacion Experimental del Zaidin, Consejo Superior de Investigaciones Cientificas (CSIC) in Granada, Spain, to develop a simplified genetic-based nomenclature that automatically catalogues the entire RF gene products into families and subfamilies. "Up to now, there has been no unified nomenclature for naming the RF proteins," Seufferheld said. "As the systematic sequencing of new plant species has increased in recent years, naming has been simply arbitrary. We have had 'chaos' in the databases. The RF information in the databases could not be adequately handled in the context of comparative functional genomics." This new tool will help plant breeders and scientists make decisions more quickly. Breeders can now easily match sterility in plants to male restorer mechanisms. Ultimately, growers may benefit sooner from new developments in plant breeding since breeders will be able to generate new hybrids at a faster pace, Jimenez-Lopez said. "Genomic sequencing, coupled with protein modeling, allowed us to begin dismantling this complexity that has held us back in the field of science," Kotchoni said. "Now we can easily compare unknown gene functions to known and well characterized genes in order to determine their functions and family hood." With many teams of researchers competing to finish this task first, Kotchoni said it has been an honor to have this model accepted as the new standard for RF protein nomenclature. This system has been developed as a building block for plant genomics. "The nomenclature, which is designed to include new RF genes as they become available in the future, is not based on one species or another, but rather on the function of the gene itself," Seufferheld said. "This allows scientists to work with a wide range of plants and take a gene with known function(s) from one plant and transfer it into another plant to restore male fertility." Corn growers only need to look back to the southern corn leaf blight epidemic in 1972 to see the importance of this scientific development. In 1972, Texas-Cytoplasm Male Sterility (T-CMS) corn was heavily used in hybrid seed production because it eliminated the costly practice of hand detasseling. Nearly 85 percent of the U.S. corn crop was produced using T-CMS, which was highly susceptible to Helminthosporium maydis, the fungus that causes southern corn leaf blight. Since then, understanding the function of RF genes in higher plants has been a priority of many researchers. "The first male sterility restorer ever characterized in plants was maize ALDH," Kotchoni said. "When this gene is altered, it causes male sterility." Seufferheld said this will also be a great tool for studying plant evolution. "We can follow how plants became domesticated," Seufferheld said. "It is easier now because we have all the structures of the RF proteins organized and can look at the evolution of these proteins in a systematic manner. If we just look at the sequence of the gene, part of the phylogenetic scene has been lost through evolution. However, the structure of protein provides more information that can go well into the past." This public gene database will allow scientists to search using the old or new names of RF proteins, Seufferheld said.

New technology improves greenhouse, plant microclimates

Wed, 29 Dec 2010 03:21:31 PDT

A study in HortTechnology featured a new technology that improved greenhouse climates by reducing solar heat radiation and temperatures during the hot summer season. The study, published by a team of Canadian researchers, was the first investigation into the effects of application of the liquid foam technology as a shading method. Results showed that the technology improved greenhouse and plant microclimates and decreased air temperature more than conventional shading curtains traditionally used by greenhouse growers. Excess temperature, solar radiation, and high vapor pressure deficit are major greenhouse concerns during the summer season. These extreme conditions increase plant stress and decrease crop productivity and fruit quality. Methods such as cooling pads and fogging systems have been used to prevent plant heat stress during the day, and various shading techniques are often used by growers to decrease solar radiation and reduce air and leaf temperatures. Shade cloths reduce the amount of solar energy entering the greenhouse and consequently decreased air temperature by partially cutting the heat portion of the solar radiation, but this incoming energy usually contains more than 50% heat (infrared radiation), which is not useful for plant growth in the summer. Sunarc of Canada, Inc. developed an innovative new shading technology that generates retractable liquid foam and distributes it between two layers of polyethylene film used as a greenhouse covering material. The Canadian research team set out to determine the effects of different shading strategies using the liquid foam technology on greenhouse and plant microclimates. The research was conducted over 2 years in two different areas of Canada, where experimental greenhouses were retrofitted with the new technology. Tomato and sweet pepper plants were used with two shading strategies: a conventional nonmovable shading curtain compared to the liquid foam shading system based only on outside global solar radiation, and foam shading applications based on both outside global solar radiation and greenhouse air temperature. The team recorded data on the greenhouse microclimate (global solar radiation, air temperature, and relative humidity), the canopy microclimate (leaf and bottom fruit temperatures), and ventilation (opening/closing). "This study showed that the retractable liquid foam technology improved greenhouse climate", noted Kamal Aberkani, lead author of the report. "Under very sunny, very hot conditions, a difference of up to 6 ºC in air temperature was noted between the unshaded and shaded greenhouses as a result of liquid foam application at 40-65% shading." According to the report, additional benefits of the technology included an increase of up to 12% in greenhouse relative humidity, a decrease in the frequency of roof ventilation operation, and an increase in the length of time bottom fruit temperature remained cool after shading ended.

K-State research looks at pathogenic attacks on host plants

Mon, 20 Dec 2010 03:27:54 PDT

Two Kansas State University researchers focusing on rice genetics are providing a better understanding of how pathogens take over a plant's nutrients. Their research provides insight into ways of reducing crop losses or developing new avenues for medicinal research. Frank White, professor of plant pathology, and Ginny Antony, postdoctoral fellow in plant pathology, are co-authors, in partnership with researchers at three other institutions, of an article in a recent issue of the journal Nature. The article, "Sugar transporters for intercellular exchange and nutrition of pathogens," was led by Li-Qing Chen from the department of plant biology in the Carnegie Institution for Science at Stanford University. The project involves the identification a family of sugar transporters, called SWEETS, which transport glucose between plant cells. These transporters are also important because they are targeted by pathogens trying to obtain plant sugar for nutrition......> Full story

Study shows garlic could protect against hip osteoarthritis

Fri, 17 Dec 2010 03:46:13 PDT

Researchers at King's College London and the University of East Anglia have discovered that women who consume a diet high in allium vegetables, such as garlic, onions and leeks, have lower levels of hip osteoarthritis. The findings, published in the BMC Musculoskeletal Disorders journal, not only highlight the possible effects of diet in protecting against osteoarthritis, but also show the potential for using compounds found in garlic to develop treatments for the condition. A relationship between body weight and osteoarthritis was previously recognised, although it is not yet completely understood. This study is the first of its kind to delve deeper into the dietary patterns and influences that could impact on development and prevention of the condition. Osteoarthritis is the most common form of arthritis in adults, affecting around 8 million people in the UK, and women are more likely to develop it than men. It causes pain and disability by affecting the hip, knees and spine in the middle-aged and elderly population. Currently there is no effective treatment other than pain relief and, ultimately, joint replacement. The study, funded by Arthritis Research UK, the Wellcome Trust and Dunhill Medical Trust, looked at over 1,000 healthy female twins, many of whom had no symptoms of arthritis. The team carried out a detailed assessment of the diet patterns of the twins and analysed these alongside x-ray images, which captured the extent of early osteoarthritis in the participants' hips, knees and spine. They found that in those who consumed a healthy diet with a high intake of fruit and vegetables, particularly alliums such as garlic, there was less evidence of early osteoarthritis in the hip joint. To investigate the potential protective effect of alliums further, researchers studied the compounds found in garlic. They found that that a compound called diallyl disulphide limits the amount of cartilage-damaging enzymes when introduced to a human cartilage cell-line in the laboratory. Dr Frances Williams, lead author from the Department of Twin Research at King's College London, says: "While we don't yet know if eating garlic will lead to high levels of this component in the joint, these findings may point the way towards future treatments and prevention of hip osteoarthritis. "It has been known for a long time that there is a link between body weight and osteoarthritis. Many researchers have tried to find dietary components influencing the condition, but this is the first large scale study of diet in twins. If our results are confirmed by follow-up studies, this will point the way towards dietary intervention or targeted drug therapy for people with osteoarthritis." Professor Ian Clark of the University of East Anglia said: "Osteoarthritis is a major health issue and this exciting study shows the potential for diet to influence the course of the disease. With further work to confirm and extend these early findings, this may open up the possibility of using diet or dietary supplements in the future treatment osteoarthritis."

Scientists unravel more details of plant cell-wall construction

Tue, 14 Dec 2010 03:26:31 PDT

One big challenge in converting plants to biofuels is that the very same molecules that keep plants standing up make it hard to break them down. Now scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory are unraveling details of how plant cells' structural supports - their cell walls - are made, with the hope of finding ways to change their composition for more efficient biofuel production. In a paper to be published the week of December 13, 2010, in the Proceedings of the National Academy of Sciences, the researchers describe details of how precursors to lignin, one important cell-wall component, are transported across cellular membranes prior to linking up. The key finding, that the process requires a class of energy-dependent transporter molecules, may provide a "chink in the armor" that opens a way to alter plants' lignin content. "Being able to manipulate lignin biosynthesis would have a great influence on our ability to produce renewable biofuels from plant cellulosic feedstocks, and could also have a large effect on many other agricultural and industrial processes, such as the production of paper and more digestible foods for grazing animals," said lead author Chang-Jun Liu, a Brookhaven biologist. Prior to cell-wall construction, lignin precursors known as monolignols are made in the cell's interior cytoplasm. Some precursors may be sequestered in internal vacuoles for storage, while some move out of the cell to link up and form the lignin component of the cell wall - a protective and supportive barrier around the cell. In both cases, the precursors move across a membrane, either out of the cell or into the vacuole. But no one was certain how the process occurred - whether by simple diffusion or via some active transport mechanism. The Brookhaven team unraveled the mystery by isolating portions of cellular and vacuolar membrane from Arabidopsis and poplar plants, making them into closed vesicles that resemble bubbles, and mixing in pure monolignols and ones that have been chemically modified to form monolignol glucosides, which are commonly observed in some plants. They then monitored which type and how much of each precursor moved across the two kinds of membranes and into the vesicles under a range of conditions, including in the presence of inhibitors for different kinds of transport molecules. The range of assays revealed that pure monolignols move across the cellular membrane while monolignol glucosides move preferentially into vacuoles. But most importantly, very little of either precursor would move across either type of membrane without the addition of ATP, the molecular "currency" for energy in cells. "ATP is the energy molecule that is well known for providing the driving force for a group of transporters called ATP-binding cassette (ABC) transporters on cell membranes," Liu said. To prove the point, adding an agent that specifically inhibits ABC transporters completely blocked uptake of lignin precursors by both types of membrane vesicles. With these experiments and additional evidence, Liu and his colleagues demonstrated that ABC-like transporters on cell membranes are responsible for the transport of lignin precursors. Now that the scientists have identified a class of transporters likely involved in sequestering and transporting lignin's building blocks, they'll pursue detailed studies to identify exactly which members of the class are involved. "If we can identify those particular transporters we might be able to control their expression to reduce the precursor deposited into the cell wall, and thus lower the cell-wall content of lignin -or, selectively control the particular type of precursor deposited to change lignin composition and produce more easily cleavable biopolymers," Liu said.

Plant disease 'stealth bomber' tactics subverted to tackle hundreds of plant pathogens

Fri, 10 Dec 2010 03:19:11 PDT

Research, led by the University of Warwick, The Sainsbury Laboratory, and Virginia Polytechnic Institute and State University (Virginia Tech), has sequenced the genome of a plant disease causing organism revealing that it acts like a "stealth bomber of plant pathogens". The research has uncovered the tactics used to sneak past the plant's immune defences. That same discovery also provides tools for researchers to identify the components of the plant immune system and devise new ways to prevent disease. The research at the University of Warwick, the Sainsbury Laboratory and Virginia Tech, was funded by the UK's Biotechnology and Biological Sciences Research Council (BBSRC), The Gatsby Charitable Foundation, NSF, and the U.S. Department of Agriculture. It looked at an obligate biotroph, a type of plant pathogen which has adapted so exquisitely to its host that it extracts nutrients only from living plant tissue and cannot grow away for their plant. While the organism may once have been able to exist by itself it has now evolved in such a way that it cannot survive without a host plant and usually that has to be a very specific type of host plant. The researchers looked specifically at Hyaloperonospora arabidopsidis, that can only survive on its host the model plant Arabidopsidis, the model plant of the plant science world. Hyaloperonospora arabidopsis is a type of water mould that causes yellow patches and fuzzy white mould on the leaves. Close relatives cause disease and damage on many crops including broccoli, maize, grapes and lettuce. The researchers found that this particular plant pathogen has evolved a highly successful strategy that allows it to present a very small profile to its host plant disease prevention defences. By losing, or never acquiring in the first place, many abilities found in other pathogens, Hyaloperonospora arabidopsidis is able to minimise the number of genetic markers it carries that could be picked up by a plant's defences and seen as a threat. The lead researcher from the University of Warwick's School of Life Sciences Professor Beynon said: "Hyaloperonospora arabidopsidis is one of the stealth bombers of the world of plant pathogens. We can see much of how it has actually slimmed down some key elements of its genetic material in order to get around the plant's natural defences - essentially by stealth." One of the key ways the University of Warwick, Sainsbury Laboratory and Virginia Tech researchers will exploit this plant pathogen's arsenal to mount their own sneak assault on many much other challenging plant pathogens is through the "RXLR effectors". Such pathogens use a large armoury of "RXLR effectors" to suppress the mechanisms used by plants to detect and then block pathogens. Although having a slimmed down stealth profile Hyaloperonospora arabidopsidis still maintains an amazing 134 RXLR effectors in its armoury. Understanding the role of these effectors will be the key direction of future research in the field. This parsimonious approach may help Hyaloperonospora arabidopsidis in its stealth attack but it also opens up a major opportunity for researchers to gain insights across a vast range of plant pathogens. Not only does Hyaloperonospora arabidopsidis infect the ideal plant model (Arabidopsis) used by plant researchers the world over for decades – it also attacks that model plant with a bare bones set of weapons that greatly simplifies a researcher's task in unpicking how those weapons work. Any insights gained can then be directly applied to the understanding of how those same weapons work in much more complicated pathogens. Professor Beynon also said: "This research provides a new window into how Hyaloperonospora arabidopsidis has slimmed down key elements of its genetic material to avoid the plant's natural defences. Despite this reduction, amazingly, it still sends over 100 proteins into plant cells to suppress the immune responses. Understanding how these proteins suppress plant immunity will enable us to select disease resistant crop plants and combat plant disease such as potato blight and sudden oak death." "Losses to disease in food crops can be very significant and to feed a growing population set to reach 9 billion by 2050 we need to increase food production. Reducing losses because of disease will be an important part of this."

New discovery about how flowering time of plants can be controlled

Wed, 08 Dec 2010 03:30:09 PDT

Researchers at Umeå Plant Science Center in Sweden discovered, in collaboration with the Syngenta company, a previously unknown gene in sugar beets that blocks flowering. Only with the cold of winter is the gene shut off, allowing the sugar beet to blossom in its second year. The discovery of this new gene function makes it possible to control when sugar beets bloom. The new findings were recently published in the prestigious journal Science. Scientists at Umeå Plant Science Center and the international company Syngenta, in a joint study of genetic regulation in the sugar beet, have discovered an entirely new principle for how flowering can be controlled. The study, which was co-directed by Professorn Ove Nilsson, of the Swedish University of Agricultural Sciences (SLU), and Syngenta scientist Dr. Thomas Kraft, showed that there is a gene in the sugar beet that was previously unknown. "When we studied a gene in the sugar beet that usually stimulates blooming in other plants, we made a very surprising discovery: in the sugar beet evolution has developed a 'sister gene' that has taken on the exact opposite function, namely, to inhibit blossoming. For biennial sugar beets this means that they can't flower in their first year. Once the plants have been exposed to the cold of winter at the end of the first year, the 'gene blockade is lifted,' and the sugar beets can bloom in their second year of life," says Ove Nilsson about the function of the newly discovered flowering gene. The researchers speculate that the development of the inhibiting sister gene was an important factor in enabling biennial sugar beets to evolve from an annual to a biennial plant. Furthermore, plant researchers in Umeå and Landskrona have shown that it is possible to manipulate the "flowering gene" in such a way as to leave the gene constantly "turned on," that is, to block blooming, and thereby prevent it from being turned off after winter. "In that way it's possible to fully control the flowering time of the sugar beet. This enables us to develop a so-called 'winter beet,' that is, a sugar beet that can be planted in the autumn and then will continue to grow throughout the following growth season without blossoming," says Thomas Kraft at Syngenta Seeds. "A winter beet has be a high priority for sugar beet growers, since it is estimated to be able to increase the yield by about 25 percent and at the same time allow a more extended harvesting period. Traditional breeding has failed to produce such a plant. Syngenta Seeds is now going to move on to more in-depth tests of this potential new winter beet."

Gene discovery suggests way to engineer fast-growing plants

Fri, 12 Nov 2010 03:24:54 PDT

Tinkering with a single gene may give perennial grasses more robust roots and speed up the timeline for creating biofuels, according to researchers at the Duke Institute for Genome Sciences & Policy (IGSP). Perennial grasses, including switchgrass and miscanthus, are important biofuels crops and can be harvested repeatedly, just like lawn grass, said Philip Benfey, director of the IGSP Center for Systems Biology. But before that can happen, the root system needs time to get established. "These biofuel crops usually can't be harvested until the second or third year," Benfey said. "A method to improve root growth could have a major role in reducing the time to harvest for warm season grasses." Benfey's team appears to have found a way to do just that. They took a directed genomic approach aimed at identifying genes that become active when cells stop dividing and start taking on the characteristics of the mature, adult cell they are to become. "We systematically looked for those genes that come 'on' precisely when cells transition from proliferation to differentiation and then turn 'off' again just as quickly," Benfey said. That genome-wide search in the roots of the familiar laboratory plant Arabidopsis and subsequent screening of mutant lines turned up a single gene, which the researchers call UPBEAT1 (UPB1). Further study showed that UPB1 controls the gene expression of enzymes known as peroxidases. They then showed that these peroxidases control the balance of free radicals between the zone of cell proliferation and the zone of cell elongation where differentiation begins. (Although free radicals are probably most familiar as agents of stress to be combated with antioxidants, Benfey noted that the balance of free radicals has also been implicated in the control of a similar transition from proliferation to differentiation in animals.) When the researchers experimentally disrupted UPB1 activity in the plant root, it altered the balance of free radicals such that cells delayed their differentiation and continued growing. Those plants ended up with faster-growing roots, having more and larger cells. When UPB1 activity was artificially increased, the growth of plant roots slowed. "It's possible that by manipulating a single gene, you could get a plant with rapid growth," Benfey said. Interestingly, UPB1 appears to act independently of plant hormones that play well-known roles in the balance between cell division and differentiation. From an engineering perspective, the prospect of enhancing growth by taking a gene away, as opposed to adding one, is particularly appealing, Benfey notes. "It also suggests that plants are not growing at their full potential," he says. That makes sense, of course, as plants in the real world have to make tradeoffs, for example, between growth and reproduction. In addition to their potential in biofuels production, the findings might also lead to new ways to produce bigger and stronger plants with the capacity to sequester more earth-warming carbon dioxide from the atmosphere, Benfey says. His startup company, GrassRoots Biotechnology Inc., has acquired the patent for this discovery with its potential in mind. The company's primary goals are the development of next-generation biofuels and the use of root systems for carbon sequestration.

To prevent inbreeding, flowering plants have evolved multiple genes, research reveals

Fri, 05 Nov 2010 03:36:48 PDT

A research team led by Teh-hui Kao, professor of biochemistry and molecular biology at Penn State University, in collaboration with a team lead by Professor Seiji Takayama at the Nara Institute of Science and Technology in Japan, has discovered a large suite of genes in the petunia plant that acts to prevent it from breeding with itself or with its close relatives, and to promote breeding with unrelated individuals. In much the same way that human inbreeding sometimes results in genetic disease and inferior health, some inbred plants also experience decreased fitness, and therefore, have developed mechanisms to ensure that their offspring benefit from hybrid vigor -- the mix that results when genetically distinct members of the same species breed. The team's discovery of the multiple inbreeding-prevention genes will be published on 5 November 2010 in the journal Science. The identification of these genes comes on the heels of Kao's earlier identification of two additional inbreeding-prevention genes in the same plant. "Humans have mechanisms to prevent inbreeding that are in part cultural," Kao explained. "But a plant can't just get up and move to the next town to find a suitable, unrelated mate. Some other system must be at work." Kao began to unravel the mystery of what he calls a "non-self recognition system" in the mid 1980s by studying the genetic sequence of petunias. Petunias and many common garden plants are hermaphroditic, possessing both male and female reproductive organs, and these reproductive organs are located in close proximity in the same flower. This floral anatomy makes it easy for a plant's pollen to land on itself, resulting in self-fertilization and genetically inferior, inbred offspring. To prevent self-fertilization, many flowering plants, including the petunia, have evolved a strategy called self-incompatibility, or the ability to recognize self and non-self components within both the male and female reproductive organs. PRIOR RESEARCH Because of the petunia's hermaphroditic nature, Kao and his colleagues assumed that there had to be both male and female genetic strategies to prevent a plant from breeding with itself or with close relatives. In 1994, Kao's team discovered the first piece of the self-incompatibility puzzle. In a paper published in Nature, he and his colleagues announced that they had identified a gene called S-RNase (S for self-incompatibility) in Petunia inflata, a wild relative of the garden petunia. The S-RNase gene controls self-incompatibility in the pistil -- the plant's female reproductive organ. Thanks to this gene, the pistil is able to distinguish between self and non-self pollen, which is analogous to sperm cells, and specifically kills self-pollen to prevent inbreeding. Later, in another paper published in Nature in 2004, Kao's team announced the discovery of the male counterpart of S-RNase -- a gene called Type-1 SLF -- that controls self-incompatibility in pollen by distinguishing between self and non-self pistil S-RNase proteins, and specifically detoxifying non-self S-RNase proteins, thereby allowing outcrossing. That is, the team found that the S-RNase and the Type-1 SLF genes worked in concert to control the way in which the plant accepted or disallowed the introduction of particular pollen into its own reproductive system. In summary, they found that, thanks to the genetic interaction between the male-component and female-component genes, a plant pollinated by its own pollen or by pollen of a similar genotype failed to produce seeds. However, a plant pollinated by pollen of a sufficiently distinct genotype produced seeds and reproduced successfully. More recently, Kao and his colleagues set out to fill in some important missing pieces in the self-incompatibility puzzle. "During previous research studies, other researchers who had studied the evolutionary histories of Type-1 SLF and S-RNase found no evidence of co-evolution, which was surprising as the male and female genes directly involved in controlling self/non-self recognition during sexual reproduction are expected to have co-evolved." Kao said. "In fact, Type-1 SLF has a much shorter evolutionary history than S-RNase." Meanwhile, Kao and his team noticed that "Type-1 SLF had a much lower allelic sequence diversity when compared to S-RNase, raising a question as to how, with limited allelic diversity, the allelic variants of Type-1 SLF proteins can recognize a large repertoire of 40 or more highly divergent S-RNase proteins," he said. "We were puzzled by how the Type-1 SLF gene seemed to have such a young evolutionary history, and how the allelic variants of Type-1 SLF protein seemed to have such a low sequence diversity. We knew that the male and female genetic counterparts had to have kept up with each other throughout evolution -- they had to have co-evolved -- so that meant there had to be older and more numerous SLF genes controlling the male side of the equation." NEW DISCOVERIES Now, in the soon-to-be-published Science paper, the team will announce its identification of five additional types of SLF genes -- named Type-2 to Type-6 SLF genes -- found in the same chromosomal region as the Type-1 SLF gene. Kao and his colleagues found that while the Type-1 SLF gene certainly played an important role in preventing inbreeding, Type-2 and Type-3, and most likely additional types of SLF genes, also controlled self-incompatibility. "Each Type-1 SLF protein can recognize only a limited number of non-self S-RNase components," Kao said. "Meanwhile, each of the additional types of SLF proteins we've found can recognize different sets of non-self S-RNase proteins, and all of them collectively account for the entire suite of non-self identification. This recent finding has solved the puzzle about the co-evolution between the male and female genes, and how a single type of SLF protein has the capacity to recognize a large number of highly divergent S-RNase proteins." Kao also explained that self-incompatibility in plants can be likened to the adaptive immune system in vertebrates. "The plant needs to distinguish between non-self and self to know which plants it should breed with and which it should reject as too similar," Kao explained. "In the same way, our bodies distinguish between non-self and self to know what to attack and what to leave alone." Kao explained that when pathogens enter our bodies, our T-cells recognize them as foreign invaders and battle against them by triggering production of antibodies by B-cells. "When this system goes awry, our bodies misidentify self as non-self and attack it," Kao said. "These attacks on our own tissues are known as auto-immune disorders; arthritis and Lupus are just a couple of examples." Kao also explained that, just as we have evolved many different types of T-cell receptors to collectively recognize the many foreign antigens we might encounter in our environment, plants have evolved many versions of self-incompatibility genes that produce multiple types of SLF proteins in pollen to collectively recognize a large suite of possible non-self elements -- S-RNase proteins. In addition to Kao, other members of the research team include Ken-ichi Kubo, Tetsuyuki Entani, Akie Takara, Mamiko Toyoda, Shin-ichi Kawashima, Akira Isogai, and Seiji Takayama from Japan's Nara Institute of Science and Technology; Ning Wang, Allison M. Fields, and Zhihua Hua from Penn State; and Toshio Ando from Japan's Chiba University. The research conducted at Penn State was funded by the National Science Foundation.

Researchers could use plant's light switch to control cells

Mon, 01 Nov 2010 03:22:18 PDT

Chandra Tucker shines a blue light on yeast and mammalian cells in her Duke University lab and the edges of them start to glow. The effect is the result of a light-activated switch from a plant that has been inserted into the cell. Researchers could use this novel "on-off switch" to control cell growth or death, grow new tissue or deliver doses of medication directly to diseased cells, said Tucker, an assistant research professor in the biology department at Duke. She and colleagues created the switch by genetically inserting two proteins from a mustard plant, Arabidopsis thaliana, into yeast cells, kidney cells and cultured rodent brain tissue. The two proteins interact under light to provide the control over cell functions. The switch is similar to one described last year where researchers genetically inserted a different light-receptive plant protein and its interacting protein partner from Arabidopsis into mammalian cells. In response to red light, these proteins interacted to cause mammalian cells to change shape, moving in the direction of the light. Tucker's switch uses Arabidopsis proteins that respond to blue light. Unlike the red-light activated proteins, which need an added cofactor, a chemical that is required for the light response, the blue-light switch doesn't need any additional chemicals to work because it uses a cofactor that naturally exists in non-plant organisms. "It's hard to deliver a chemical to a fly or to individual cells. This new approach, with one of the molecules already in the mammalian or yeast cells, makes building a light-controlled switch a lot easier," Tucker said. Her team describes the switch in the Oct. 31 Nature Methods. To test the switch, the team fused one of the light-sensitive Arabidopsis proteins to a red fluorescent protein and the other to a green fluorescent protein, which was in turn attached to the cell membrane. When the researchers flashed blue light on the cell, the plant proteins interacted, causing the red fluorescent protein to rapidly move to the cell membrane, which then glowed yellow due to the merging of the red and green fluorescing proteins. The team found that this interaction was reversible and could be triggered repeatedly with light exposure. The switch is one among several that have been designed to give researchers better control of different functions of the cell. The next step in developing the switch will be to make the interacting proteins more effective, Tucker said. The approach is expected to be applicable not only for studies in cultured cells and yeast, but also worms, fruit flies, mice and other model organisms. Eventually this method could allow researchers to test how cells in a tissue affect neighboring cells in a tissue, to guide axon growth in neurons to repair brain tissue, or even to kill cancer cells. Tucker's new approach will be a "major boon" to those who wish to apply light activation to their own experimental systems, said Klaus Hahn, a pharmacologist at the University of North Carolina at Chapel Hill, whose lab reported on another blue-light responsive protein to control movement of mammalian cells last year. Hahn said the "elegant work will likely see broad use, in many fields and for applications that will surprise us," and it is already going to be applied to important areas of research, such as control of gene expression.

Transgenic corn suppresses European corn borer, saves farmers billions

Fri, 08 Oct 2010 03:24:02 PDT

Transgenic corn's suppression of the European corn borer has saved Midwest farmers billions of dollars in the past decade, reports a new study in Science. Research conducted by several Midwest universities shows that suppression of this pest has saved $3.2 billion for corn growers in Illinois, Minnesota, and Wisconsin over the past 14 years with more than $2.4 billion of this total benefiting non-Bt corn growers. Comparable estimates for Iowa and Nebraska are $3.6 billion in total, with $1.9 billion accruing for non-Bt corn growers. Transgenic corn is engineered to express insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). Bt corn has become widely adopted in U.S. agriculture since its commercialization in 1996. In 2009, Bt corn constituted 63 percent of the U.S. crop. Corn borer moths can't distinguish between Bt and non-Bt corn, so females lay eggs in both types of fields. Once eggs hatch in Bt corn, young borer larvae feed and die within 24 to 48 hours. The major benefit of planting Bt corn is reduced yield losses, and Bt acres received this benefit after the growers paid Bt corn technology fees. But as a result of areawide pest suppression, non-Bt acres also experienced yield savings without the cost of Bt technology fees, and thus received more than half of the benefits from growing Bt corn in the region. "We've assumed for some time that economic benefits were accruing, even among producers who opted not to plant Bt hybrids," said co-author of the study Mike Gray, University of Illinois Extension entomologist and professor in the Department of Crop Sciences. "However, once quantified, the magnitude of this benefit was even more impressive." Over the past several years, entomologists and corn producers have noticed very low densities of European corn borers in Illinois. In fact, Illinois densities have reached historic lows to the point where many are questioning its pest status, Gray said. "Since the introduction of Bt corn, initially targeted primarily at the European corn borer, many entomologists and ecologists have wondered if population suppression over a large area would eventually occur," Gray said. "As this research shows, areawide suppression has occurred and dramatically reduced the estimated $1 billion in annual losses caused previously by the European corn borer." This information also provides incentives for growers to plant non-Bt corn in addition to Bt corn. "Sustained economic and environmental benefits of this technology will depend on continued stewardship by producers to maintain non-Bt maize refuges to minimize the risk of evolution of Bt resistance in crop pest species," Gray said.

Ecologists find new clues on climate change in 150-year-old pressed plants

Wed, 22 Sep 2010 03:21:58 PDT

Plants picked up to 150 years ago by Victorian collectors and held by the million in herbarium collections across the world could become a powerful – and much needed – new source of data for studying climate change, according to research published this week in the British Ecological Society's Journal of Ecology. The scarcity of reliable long-term data on phenology – the study of natural climate-driven events such as the timing of trees coming into leaf or plants flowering each spring – has hindered scientists' understanding of how species respond to climate change. But new research by a team of ecologists from the University of East Anglia (UEA), the University of Kent, the University of Sussex and the Royal Botanic Gardens, Kew shows that plants pressed up to 150 years ago tell the same story about warmer springs resulting in earlier flowering as field-based observations of flowering made much more recently. The team examined 77 specimens of the early spider orchid (Ophrys sphegodes) collected between 1848 and 1958 and held at the Royal Botanic Gardens, Kew and the Natural History Museum in London. Because each specimen contains details of when and where it was picked, the researchers were able to match this with Meteorological Office records to examine how mean spring temperatures affected the orchids' flowering. They then compared these data with field observations of peak flowering of the same orchid species in the Castle Hill National Nature Reserve, East Sussex from 1975 to 2006, and found that the response of flowering time to temperature was identical both in herbarium specimens and field data. In both the pressed plants and the field observations, the orchid flowered 6 days earlier for every 1oC rise in mean spring temperature. The results are first direct proof that pressed plants in herbarium collections can be used to study relationships between phenology and climate change when field-based data are not available, as is almost always the case. According to the study's lead author, PhD student Karen Robbirt of UEA: "The results of our study are exciting because the flowering response to spring temperature was so strikingly close in the two independent sources of data. This suggests that pressed plant collections may provide valuable additional information for climate-change studies." "We found that the flowering response to spring temperature has remained constant, despite the accelerated increase in temperatures since the 1970s. This gives us some confidence in our ability to predict the effects of further warming on flowering times." The study opens up important new uses for the 2.5 billion plant and animal specimens held in natural history collections in museums and herbaria. Some specimens date back to the time of Linnaeus (who devised our system of naming plants and animals) 250 years ago. Co-author Professor Anthony Davy of UEA says: "There is an enormous wealth of untapped information locked within our museums and herbaria that can contribute to our ability to predict the effects of future climate change on many plant species. Importantly it may well be possible to extend similar principles to museum collections of insects and animals." Phenology – or the timing of natural events – is an important means of studying the impact of climate change on plants and animals. "Recent climate change has undoubtedly affected the timing of development and seasonal events in many groups of organisms. Understanding the effects of recent climate change is a vital step towards predicting the consequences of future change. But only by elucidating the responses of individual species will we be able to predict the potentially disruptive effects of accelerating climate change on species interactions," he says. Detecting phenological trends in relation to long-term climate change is not straightforward and relies on scarce long-term studies. "We need information collected over a long period to enable us confidently to identify trends that could be due to climate change. Unfortunately most field studies are relatively brief, so there are very few long-term field data available," Professor Davy explains

AgriLife research hibiscus breeder comes up with the blue

Sat, 04 Sep 2010 04:16:36 PDT

Dr. Dariusz Malinowski is seeing blue, and he is very excited. For four years, Malinowski, an AgriLife Research plant physiologist and forage agronomist in Vernon, has been working with collaborators Steve Brown of the Texas Foundation Seed and Dr. William Pinchak and Shane Martin with AgriLife Research on a winter-hardy hibiscus breeding project. The project was first a private hobby of the inventors and became a part of the strategic plan of the Texas AgriLife Research and Extension Center at Vernon in 2009. The flower commercialization is a part of the research on non-traditional or under-utilized crops that have value because of drought tolerance. Malinowski's breeding goal has been to create a blue-flowering winter-hardy hibiscus. "A blue pigment does not exist in this species, thus hybridizers have not been successful so far in creating a plant with blue flowers," he said. "There are a couple of recently introduced cultivars with plum and lavender flower color." But now Malinowski has managed to breed a flower with the illusive color. He and his collaborators have created a number of lines with unique flower and foliage shape and color. The new hibiscus hybrids range in color from white through different shades of pink, lavender, bluish, red and magenta tones, and some of them have combinations of two or even three colors. One line has dark maroon foliage with moderately big, white flowers that blend into a pink center with darker veins, Malinowski said. Flower size of these hybrids varies from miniature blooms 2 inches in diameter to the size of dinner plates, about 12 inches in diameter. Malinowski has been using these cultivars in his breeding project for several generations. This year, they finally had one plant bloom with almost blue flowers, a significant breakthrough in efforts to create a blue hibiscus cultivar. "It took four years of work and more than 1,000 crosses among three winter-hardy hibiscus species to achieve this goal of creating an almost-blue flowering hibiscus hybrid," he said. The new hybrid is not perfect yet, Malinowski said. "The flowers get a fantastic blue hue in shade, but in full sunlight they are still plum-lavender-bluish," he said. Brown said it is important to note that in the world of ornamentals, "blue" is interpreted to have a wide range of hues. Most ornamental blues have a more purple or lavender cast. "There are very few true blue flowers in any ornamental cultivar," he said. "Although I would call this flower 'almost blue' as Dariusz has, there is no question that this development is unique in known hardy hibiscus color ranges. "My expectation is that we will see more vibrant colors in next year's F1s (cultivars) using this line as a parent," Brown said. Malinowski said he will use this plant as a parent in his breeding project this summer, with the goal to stabilize the blue color in full sunlight and increase flower size from the current 7 inches to the "magic" 12-inch diameter. Breeding of ornamental plants is not the major research area of Malinowski, but he said he enjoys new challenges and the benefits of combining his private hobby with business. "I never thought I would be an expert in breeding winter-hardy hibiscus," he said. "The knowledge I have gained during the past few years of intensive work on hardy hibiscus helps me reach most of the breeding objectives in a relatively short time." What is next? Malinowski and his collaborators have a new challenge - to create an orange flowering hardy hibiscus. This goal seems to be even more difficult, but not impossible, Malinowski said. It will require hybridization with a distantly related hibiscus species, which has shades of orange flowers. The researchers hope that with the help of molecular genetic tools they will be able to meet this objective.

Core knowledge of tree fruit expands with apple genome sequencing

Mon, 30 Aug 2010 03:24:19 PDT

An international team of scientists from Italy, France, New Zealand, Belgium and the USA have published a draft sequence of the domestic apple genome in the current issue of Nature Genetics. The availability of a genome sequence for apple will allow scientists to more rapidly identify which genes provide desirable characteristics to the fruit and which genes and gene variants provide disease or drought resistance to the plant. This information can be used to rapidly improve the plants through more informed selective breeding. An organism's genome is the total of all its genetic information, including genes. Genes carry information that determines, among other things, a plant's appearance, health, productivity and color and taste of the fruit. The domestic apple is the main fruit crop of the world's temperate regions. Apple is a member of the plant family Rosaceae which includes many other economically important species, including cherry, pear, peach, apricot, strawberry, and rose, to name just a few. The state of Washington accounts for approximately 60 percent of total apple production in the U.S. and Rosaceae fruit production is a multi-billion dollar industry in the state. Washington state scientists played an important role in the project. Led by Washington State University horticultural genomicist Amit Dhingra, the Washington-based team sequenced and analyzed a unique version of the genome of the golden delicious apple in which all duplicated chromosomes are genetically identical. This information was used to validate the sequence of the more complicated "heterozygous" golden delicious apple (in which duplicated chromosomes are not identical). "Before genome sequencing, the best we could do was correlate traits with genes. Now we can point to a specific gene and say, 'This is the one; this gene is responsible for this trait'. That trait of interest might be, for instance, a disease, which is why sequencing the human genome was such an important milestone. Or the trait might be for something desirable, like flavor in a piece of fruit. We are already working on finding physiological solutions to issues like bitter pit in current apple varieties with the gene-based information available to us and lay a foundation for improved varieties in the future through generation of sports (mutations) and breeding," Dhingra said. The Washington state contribution to the sequencing work was a unique collaboration between the cross-state Apple Cup rivals of WSU and the University of Washington. Microbiologist Roger Bumgarner's lab at the University of Washington provided the initial sequencing expertise and capability to the project, which was later complemented and replaced by sequencing expertise in the Dhingra genomics lab, who obtained the same DNA sequencing instrument used in Dr. Bumgarner's lab. "UW is a world leader in medical research and WSU is a world leader in agricultural research," said Bumgarner. "Technological advancements and techniques initially used to study medically important genomes and problems can be rapidly applied to genomes and problems of agricultural importance. We both had something to contribute and to learn from one another. I think there are many more opportunities for such collaborations to develop in the coming years." After the sequencing was completed, WSU computational biologist Ananth Kalyanaraman contributed to the analysis by comparing the apple genome with that of pear, peach and grape to identify the differences and commonalities that exist between these fruit crops. While the apple genome provides a valuable resource for future research, one pressing question answered by the international team's paper in Nature Genetics was one of origin. Scientists have long wanted to know — and have for years argued vehemently about — the ancestor of the modern domesticated apple. The question is now settled: Malus sieversii, native to the mountains of southern Kazakhstan, is the apple's wild ancestor. Now that that question is settled, scientists will begin using the apple genome to help breed apples with desirable new traits, including disease resistance and, potentially, increased health-benefitting qualities. "Having the apple genome sequence will greatly accelerate our ability to define the differences between apple cultivars at the genetic level," said Kate Evans, an apple breeder based at the WSU Tree Fruit Research and Extension Center. "This will allow us to exploit these differences and target areas of diversity to incorporate into the breeding program, resulting in improved cultivars for the consumers that are also better suited for long-term, sustainable production." Dan Bernardo, dean of the WSU College of Agricultural, Human, and Natural Resource Sciences, said, "The Washington apple is an icon of quality around the globe. This is a natural home for the advanced science necessary to map the tree fruit genome and actively study how it functions."

Researchers discover novel mechanism protecting plants against freezing

Fri, 27 Aug 2010 03:21:09 PDT

New ground broken by Michigan State University biochemists helps explain how plants protect themselves from freezing temperatures and could lead to discoveries related to plant tolerance for drought and other extreme conditions. "This brings together two classic problems in plant biology," said Christoph Benning, MSU professor of biochemistry and molecular biology. "One is that plants protect themselves against freezing and that scientists long thought it had something to do with cell membranes, but didn't know exactly how. "The other is the search for the gene for an enigmatic enzyme of plant lipid metabolism in the chloroplasts," in other words, how lipids, which are membrane building blocks, are made for the plant cell organelles responsible for converting solar energy into chemical energy by photosynthesis. In an article published online this week by the journal Science, Benning and his then-doctoral degree candidate Eric Moellering and technical assistant Bagyalakshmi Muthan describe how a particular gene leads to the formation of a lipid that protects chloroplast and plant cell membranes from freeze damage by a novel mechanism in Arabidopsis thaliana, common mustard weed. Working on his dissertation project under Benning, Moellering identified a mutant strain of Arabidopsis that can't manufacture the lipid and linked this biochemical defect to work done by others who originally described the role of the gene in freeze tolerance, but did not find the mechanism. "One of the big problems in freezing tolerance or general stress in plants is that some species are better at surviving stress than others," Moellering said. "We are only beginning to understand the mechanisms that allow some plants to survive while others are sensitive." There is no single mechanism involved in plant freezing tolerance, Moellering added, so he can't say that his findings will lead any time soon to genetic breakthroughs making citrus or other freezing-intolerant plants able to thrive in northern climates. But it does add to our understanding of how plants survive temperature extremes. Much plant damage in freezing temperatures is due to cell dehydration, in which water is drawn out as it crystallizes and the organelle or cell membrane shrivels as liquid volume drops. Lipids in the membranes of tolerant plants are removed and converted to oil that accumulates in droplets, the researchers said, retaining membrane integrity, keeping membranes from fusing with one another and conserving the energy by storing oil droplets. With rising concern globally about water supplies and climate change, scientists see additional reasons to understand the ways hardy plants survive. The research, funded by the U.S. Department of Energy Office of Science Basic Energy Sciences and the Michigan Agricultural Experiment Station, also leads to speculation that freezing itself can prompt cell proteins directly to change the composition of the membrane, without activation by gradual acclimation. That has been a major focus in the plant freezing tolerance field, the researchers said. "This opens a huge door now for people to do this kind of research, and to redirect researchers," Benning said. "There are lots of them out there trying to understand cold, salt and drought tolerance in plants, and we've given them a new idea about how they can approach this problem mechanistically."

UK researchers release draft sequence coverage of wheat genome

Fri, 27 Aug 2010 03:16:47 PDT

A team of UK researchers, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), has publicly released the first sequence coverage of the wheat genome. The release is a step towards a fully annotated genome and makes a significant contribution to efforts to support global food security and to increase the competitiveness of UK farming. The genome sequences released comprise five read-throughs of a reference variety of wheat and give scientists and breeders access to 95% of all wheat genes. This is among the largest genome projects undertaken, and the rapid public release of the data is expected to accelerate significantly the use of the information by wheat breeding companies. The team involved Prof Neil Hall and Dr Anthony Hall at the University of Liverpool, Prof Keith Edwards and Dr Gary Barker at the University of Bristol and Prof Mike Bevan at the John Innes Centre, a BBSRC-funded Institute. Prof Edwards said: "The wheat genome is five times larger than the human genome and presents a huge challenge for scientists. The genome sequences are an important tool for researchers and for plant breeders and by making the data publicly available we are ensuring this publicly funded research has the widest possible impact." Universities and Science Minister David Willetts said: "This is an outstanding world class contribution by the UK to the global effort to completely map the wheat genome. By using gene sequencing technology developed in the UK we now have the capability to improve the crops of the future by simply accelerating the natural breeding process to select varieties that can thrive in challenging conditions." The genome data released are in a 'raw' format, comprising sequence reads of the wheat genome in the form of letters representing the genetic 'code'. A complete copy of the genome requires further read-throughs, significant work on annotation and the assembly of the data into chromosomes. Large-scale, rapid sequencing programmes such as this have been made technically feasible by advanced technology genome sequencing platforms, including one based on BBSRC-funded research conducted in the UK in the 1990s.The majority of the sequencing work for this particular project was done using the 454 Life Science platform, developed in the US. Prof Hall said: "The genome sequence data of this reference variety, Chinese Spring wheat, will now allow us to probe differences between varieties with different characteristics. By understanding the genetic differences between varieties with different traits we can start to develop new types of wheat better able to cope with drought, salinity or able to deliver higher yields. This will help to protect our food security while giving UK plant breeders and farmers a competitive advantage." The sequence data can be used by scientists and plant breeders to develop new varieties through accelerated conventional breeding or other technologies. Prof Bevan, a member of the Coordinating Committee of the International Wheat Genome Sequencing Consortium, said: "The sequence coverage will provide an important foundation for international efforts aimed at generating a complete genome sequence of wheat in the next few years." Prof Doug Kell, BBSRC Chief Executive, said: "Recent short-term price spikes in the wheat markets have shown how vulnerable our food system is to shocks and potential shortages. The best way to support our food security is by using modern research strategies to understand how we can deliver sustainable increases in crop yields, especially in the face of climate change. Genome sequencing of this type is an absolutely crucial strategy, building on previous BBSRC-funded work. Knowledge of these genome sequences will now allow plant breeders to identify the best genetic sequences to use as markers in accelerated breeding programmes." Dr Jane Rogers, Member of the Coordinating Committee of the International Wheat Genome Sequencing Consortium and Director of BBSRC's The Genome Analysis Centre, said: "The public release of the wheat genome data will be a useful resource for scientists and the plant breeding community and will provide a foundation to identify genetic differences between wheat varieties. In recent years genomics technology has advanced to a point that scientists can now produce sequence data for plants with genomes as large as wheat at a rate unimaginable a few years ago. This is an impressive achievement, notwithstanding the significant hurdles we still face to fully interpret and understand the data." A key feature of this research has been the quick release of the data into the public domain to allow other scientists and wheat breeding companies to rapidly employ it in practical applications. Richard Summers, Vice Chairman of the British Society of Plant Breeders, said: "The wheat breeding community has been greatly impressed with the collaborative approach taken in this project. The team brought together world class skills in sequencing and wheat genetics to deal with a major barrier in wheat breeding. This is an excellent example of how to achieve technology transfer from research lab through to practical deployment."

Electrifying findings: New ways of boosting healthful antioxidant levels in potatoes

Mon, 23 Aug 2010 03:11:10 PDT

Here's a scientific discovery fit to give Mr. Potato Head static cling and flyaway hair (if that vintage plastic toy had hair). Scientists today reported discovery of two simple, inexpensive ways of boosting the amounts of healthful antioxidant substances in potatoes. One involves giving spuds an electric shock. The other involves zapping them with ultrasound, high frequency sound waves. Those new insights into improving the nutritional content of one of the Western world's favorite side dishes were reported today at the 240th National Meeting of the American Chemical Society (ACS), being held here this week. The study was among nearly 8,000 scientific reports scheduled for presentation at the meeting, one of the largest scientific gatherings of 2010. "We found that treating the potatoes with ultrasound or electricity for 5-30 minutes increased the amounts of antioxidants –– including phenols and chlorogenic acid –– by as much as 50 percent," said Kazunori Hironaka, Ph.D., who headed the research. "Antioxidants found in fruits and vegetables are considered to be of nutritional importance in the prevention of chronic diseases, such as cardiovascular disease, various cancers, diabetes, and neurological diseases." Hironaka, who is with Obihiro University in Hokkaido, Japan, indicated that the process could have widespread commercial application, due to growing consumer interest in so-called "functional foods." Those are products like berries, nuts, chocolate, soy, and wine that may have health benefits beyond traditional nutrition. Such foods may promote overall good health, for instance, or reduce the risk of specific diseases. Hironaka estimated that sales of such products in the United States alone now approach $20 billion annually. "We knew from research done in the past that drought, bruising, and other stresses could stimulate the accumulation of beneficial phenolic compounds in fresh produce," Hironaka explained. "We found that there hasn't been any research on the healthful effects of using mechanical processes to stress vegetables. So we decided in this study to evaluate effect of ultrasound and electric treatments on polyphenols and other antioxidants in potatoes." The ultrasound treatment consisted of immersing whole potatoes in water and subjecting them to ultrasound for 5 or 10 minutes. For the electrical treatment, the scientists immersed potatoes in a salt solution for 10 seconds and subsequently treated the spuds with a small electrical charge for 10, 20, and 30 minutes. The study team then measured antioxidant activity and the phenolic content and concluded that the stresses increased the amount of these compounds. The 5 minutes of ultrasound, for instance, increased polyphenol levels by 1.2 times and other antioxidants by about 1.6 times.

New genetic tool helps improve rice

Fri, 20 Aug 2010 03:25:45 PDT

U.S. Department of Agriculture (USDA) scientists have developed a new tool for improving the expression of desirable genes in rice in parts of the plant where the results will do the most good. Roger Thilmony, a geneticist with USDA's Agricultural Research Service (ARS), has shown that the LP2 gene promoter can be used to direct other introduced genes to express beneficial traits in specific plant tissues without the potential for causing unintended consequences. Thilmony works at the ARS Crop Improvement and Utilization Research Unit in Albany, Calif. ARS is USDA's principal intramural scientific research agency. Rice is under constant threat from pathogens such as rice blast, a fungus found in fields worldwide, and sheath blight, a continuing threat to U.S. growers. Scientists who develop disease-resistant varieties often find that introducing a gene may prevent disease in one part of the plant, but also may reduce seed quality or produce other "side effects" because the gene is expressed throughout the plant. Tissue-specific promoters, such as LP2, are segments of genes that can direct the activity of introduced genes only to parts of the plant where the beneficial traits are needed. Thilmony and his ARS colleagues Mara Guttman, James Thomson and Ann Blechl found that the gene they named LP2 is consistently expressed in green tissues. In experiments, they fused the LP2 promoter with a "reporter gene" known to produce a specific enzyme, and inserted that fused DNA package into seven lines of rice to see where the enzyme would be produced. They found that the LP2 promoter steered expression of the reporter gene specifically to green tissues where photosynthesis occurs. The reporter gene enzyme activity was highest in the leaves, and nearly undetectable in the roots, seeds and flower parts. The LP2 promoter could be used to improve varieties of rice, barley and wheat and could aid in the development of biofuel crops, in which scientists need to control leaf traits without affecting other tissues, according to Thilmony. The researchers published their work in Plant Biotechnology Journal and have filed a provisional patent on use of the LP2 promoter. This research supports the USDA priority of promoting international food security.

Insects sense danger on mammals' breath

Tue, 10 Aug 2010 03:42:53 PDT

When plant-eating mammals such as goats chomp on a sprig of alfalfa, they could easily gobble up some extra protein in the form of insects that happen to get in their way. But a new report in the August 10th issue of Current Biology, a Cell Press publication, shows that plant-dwelling pea aphids have a strategy designed to help them avoid that dismal fate: The insects sense mammalian breath and simply drop to the ground. "Tiny insects like aphids are not helpless when facing large animals that rapidly consume the plants they live on," said Moshe Inbar of the University of Haifa in Israel. "They reliably detect the danger and escape on time." Inbar said he had always wondered about accidental predation of small plant-dwellers based on his observations of insects that don't really move around. "As soon as we started to work on this problem, we suspected that the aphids responded to our own breath," he said. (The researchers later used snorkels to keep their own breath from mucking up their experiments). The researchers allowed a goat to feed on potted alfalfa plants infested with aphids. "Strikingly, 65 percent of the aphids in the colonies dropped to the ground right before they would have been eaten along with the plant," the researchers write. That mass dropping might have been triggered by many cues: plant shaking, sudden shadowing, or the plant-eater's breath. While a quarter of the aphids dropped when plants were shaken, more than half fell to the ground in response to a lamb's breath, the researchers report. Shadows had no effect on the aphids' dropping behavior. Ladybugs, an insect enemy of aphids, didn't inspire that kind of synchronous response either. Further studies with an artificial breath apparatus allowed the researchers to test what it was about the breath that tipped the aphids off. It turned out it wasn't carbon dioxide or other known chemical ingredients found on mammalian breath. Only when the controlled airstream was both warm and humid did it lead to impressive dropping rates of 87 percent in a room with otherwise low humidity. Inbar said that the aphids' "elegant solution" to the problem of incidental predation is likely practiced by other species as well. "This remarkable response to mammalian-specific cues, in spite of the inherent cost of an aphid's dropping off the plant, points to the significance of mammalian herbivory to plant-dwelling insects," the researchers concluded. "We predict that this sort of escape behavior in response to mammalian breath may be found among other invertebrates that live on plants and face the same threat."