The International Rice Research Institute is an international independent research and training organization with headquarters in Los Baños, Laguna in the Philippines and offices in sixteen countries. The non-governmental organization was established in 1960 to develop new rice varieties and rice crop management techniques with finding sustainable ways to improve the well-being of poor rice farmers and consumers as well as the environment in mind.The institute is one of 15 agricultural research centers on the world that form CGIAR. It is also the largest non-profit agricultural research center in Asia.IRRI received the 2010 BBVA Foundation Frontiers of Knowledge Award in the category of Development Cooperation. Wikipedia.
News Article | April 26, 2017
Plant biologist Krishna Niyogi opens the doors of growing cabinets in his lab at the University of California, Berkeley, revealing rows of tobacco and Arabidopsis plants. Under the warm solar lamps, vibrant green algae thrives in rotating flasks and streaked on petri dishes. For the past 20 years or so, Niyogi has been using these plants to study photosynthesis, mutating one gene at a time to uncover the molecular mechanisms behind plants' responses to shifting light levels. The green world inside the cabinets may seem distant from the reality of growing maize (corn) in Iowa or rice in Cambodia, but think again. Last November, Niyogi and his colleagues showed that engineering photosynthesis can improve crop yields in field-grown tobacco plants (Nicotiana tabacum). The researchers are now translating their modifications to food crops. Mindful of the growing global population, non-profit organizations and governments around the world are investing in research to optimize photosynthesis in the hope of improving the yield of crops such as rice, wheat and cowpeas. “Photosynthesis is a bit of an underachiever,” says Jeremy Harbinson, a plant scientist at Wageningen University in the Netherlands. Photosynthesis is inefficient and, despite it being one of the best understood processes in plants, it hasn't been exploited by agronomists to boost crop production, Harbinson explains. While researchers, such as Niyogi, are engineering plants to use sunlight more efficiently, others are working to improve the reactions that capture carbon dioxide or, even more ambitiously, reinvent a plant's metabolism and anatomy. During the middle of the last century, amid warnings of famines, scientists made a concerted effort to modernize agriculture. As part of the green revolution, agronomists used conventional breeding techniques to improve yields, producing plants with shorter stalks, for example, that focus their energy on making more seeds instead. They also encouraged the use of fertilization, irrigation and pest-control methods. These advances meant global production of wheat, rice and maize doubled from around 1 billion tonnes of grain in 1960 to 2 billion tonnes in 2000. A food-supply crisis was averted. The prospect of world hunger looms again, however. To feed 2050's expected population of 9.7 billion people, the Food and Agriculture Organization (FAO) of the United Nations estimates that global agricultural production will have to rise by about 50%, and double in developing countries, assuming levels of food loss and waste do not change. But the techniques that have increased yields since the 1960s may have hit a ceiling. In wheat and rice in particular, plant biologists are seeing limited improvements. “We've been living off those gains for 50 years,” says Robert Furbank, director of the Australian Research Council Centre of Excellence for Translational Photosynthesis in Acton. “We have to look at radical solutions.” Reducing food loss and waste (see page S6), and making more-sustainable dietary choices (see page S18) will help. But increasing the potential yield of crops to produce more food without using extra land, water or fertilizer would be a powerful boost to ensuring people have access to enough food. The hope is that with genetic modification of photosynthesis we will enter a new era of yield improvements. Photosynthesis is the chain of metabolic reactions through which plants convert energy from the Sun, CO and water into the molecules they need. The process converts only about 5% of the energy that plants receive into biomass. “You would think a billion years of evolution would have optimized photosynthesis by now,” says Niyogi, but things aren't so simple. For one thing, cultivated crops face different limiting factors to wild plants. “In nature, plants are usually limited by drought stress, nutrients and pathogens,” he says. But modern farming methods and tools such as irrigation, fertilizer and pesticides have lessened these challenges, affording cultivated crops the luxury of bumping up against the inefficiencies of light absorption. Niyogi's research centres on a fundamental process called photoprotection. High levels of sunlight can damage plant cells, so to protect themselves they make pigments that temporarily deflect excess energy when sunlight is too bright — a botanical sunscreen. When the light levels shift, perhaps because of the movement of leaves that shade others or a change in cloud cover, plant cells ramp photosynthesis back up — but it takes a few minutes. In densely planted crops, where a canopy of leaves creates dynamic patterns of light and shade, a lot of productive time is lost to this photoprotection lag. Niyogi's research focuses on a photoprotection mechanism called non-photochemical quenching (NPQ), which reduces yield by an estimated 20%. His group has had promising results from the upregulation of three genes in tobacco involved in two forms of NPQ that include the protective pigment zeaxanthin. But positive results in the lab are no guarantee of success in a field crop. It can be difficult to get plants to stably express new genes over multiple generations. And of course, field conditions can vary widely from the controlled environment inside growth cabinets. Niyogi's team is part of a multi-institution project — called Realizing Increased Photosynthetic Efficiency (RIPE) — to increase the yield of food crops in developing countries through photosynthesis. As part of the programme, the Berkeley researchers worked with plant biologist Stephen Long, who directs the wider RIPE project, and his team at the University of Illinois at Urbana–Champaign to do field tests of the engineered light-handling mechanism in tobacco. Tobacco is a good model for studying photoprotection because it has a dense canopy of leaves, like maize. RIPE's computer models, which simulate the reactions of photosynthesis, predicted a 20% improvement in yield for tobacco plants with genetically altered NPQ pathways. That's a big change — an improvement of just a few per cent achieved without upping the pressure on land, water or fertilizer would make a significant difference to farmers. Because this kind of research can be difficult to translate to field trials, when the researchers measured the dry weight, and saw the tobacco yield had been boosted by 15%1, they were delighted. “Yes! We got more!” Long says. They are now planning to test whether the photoprotection boost works in cowpea (Vigna unguiculata), a major source of protein in sub-Saharan Africa, in partnership with researchers at the Commonwealth Scientific and Industrial Research Organisation in Australia and cowpea breeders in West Africa. And in Illinois, the researchers are translating the work to rice. Tinkering with photoprotection is not the only way to improve plants' use of light energy. Anastasios Melis, a plant biologist at the University of California, Berkeley, is working on reducing the amount of the pigment chlorophyll inside chloroplasts, plants' photosynthetic organelles. Melis knows that this sounds counter-intuitive. But consider the way in which a canopy of densely planted crops shades many of the leaves below, he says. More-transparent leaves with less chlorophyll will allow more light to pass through to lower leaves — improving the productivity of the plant as a whole. Researchers are also studying the infrared-absorbing chlorophylls made by some types of photosynthetic cyanobacteria2. Infrared radiation is normally considered to be outside the range that can be used by plants for photosynthesis. If scientists can map out the details of how bacterial chlorophylls are produced, and integrate them into crops, the number of available photons could increase by about 19%, allowing the modified plants to capture more solar energy. “We cannot change the intensity of the sunlight,” says Melis. “We just have to make better use of it.” The solar energy that plants capture is used to make chemical energy inside the cell. This is then used to fix CO and make sugars. This second stage, called the Calvin cycle, could also be made more efficient. Rubisco is one of the most important enzymes in the Calvin cycle, but the CO fixing enzyme is prone to errors. “Every fourth turnover, it fixes an oxygen molecule instead of CO ,” explains Donald Ort, a plant biologist for the US Department of Agriculture who is based at the University of Illinois at Urbana–Champaign. This chemical error, known as photorespiration, generates a toxic compound called glycolate that plants must break down. When photosynthetic cells first evolved, there was very little oxygen in the atmosphere, so the fact that rubisco couldn't always distinguish oxygen from CO wasn't a problem. Researchers think that by the time oxygen levels were high enough to be a problem, the enzyme was too established and complex to be improved through evolution. Instead, plants make rubisco in large quantities so there is always enough to fix the CO needed. The enzyme is thought to be the most abundant on Earth. Although higher levels of CO in the atmosphere boost photosynthesis, human activities that increase the level of CO will not improve rubisco's odds. The enzyme makes more mistakes at higher temperatures, and plant scientists expect that photorespiration will increase as a result of rising global temperatures — to the detriment of crop yields. For many years, researchers were uncertain whether there was much variation in rubisco, says Elizabete Carmo-Silva, a plant scientist at Lancaster University, UK. But improvements in technology that allows photosynthetic phenotypes to be measured in the field have shown that this isn't true. Carmo-Silva's group is studying rubisco and rubisco activase (which helps restore the carbon-fixing enzyme after it makes a mistake) in wheat strains. The work is ongoing, but the team has already found variants of these enzymes that recover more quickly than typical rubisco after fixing oxygen. These variants could be bred into the germplasm, the genetic material that's used to develop seeds, she says (see page S8). Ort is focused on streamlining the reactions that plants use to break down glycolate. These type of reactions use a lot of energy and require chemical intermediates to be shuttled between chloroplasts, mitochondria and organelles called peroxisomes. “This lowers the efficiency of photosynthesis by about 30 or 40% — it's huge,” says Ort. Organisms, such as the bacterium Escherichia coli, have more-efficient reaction pathways for metabolizing glycolate than the complex pathways that evolved in plants. When researchers tried to introduce this bacterial mechanism into Arabidopsis, they found that photosynthesis was boosted only modestly3. Ort suspects that this is because plant cells were still shipping glycolate out of the chloroplast even with the introduction of the improved chemical pathway. Ort has developed tobacco plants with chloroplasts that lack glycolate transporters, and so are forced to metabolize the compound in that organelle using the more-efficient pathway. Preliminary results suggest that these plants had a 20–30% increase in biomass. Before submitting the work for publication, Ort plans to replicate the results in a second field experiment this year. Although plants haven't developed an alternative to rubisco, a more-efficient form of photosynthesis has independently evolved more than 60 times. C photosynthesis, in which the first step involves producing a four-carbon compound instead of a three-carbon one, is about 50% more efficient than the C process because it uses a more-effective enzyme to capture CO . This is especially true for plants living in dry, hot conditions, says Jane Langdale, a plant biologist at the University of Oxford, UK. Langdale is part of the C Rice Project, which aims to transform rice from a C into a C plant. The project was conceived in 1999 by John Sheehy, a plant physiologist at the International Rice Research Institute (IRRI) in Los Baños, Philippines, and the project's scientists would be the first to admit that their goal is ambitious. To make rice into a C plant, researchers must endow it not only with new metabolic networks, but also with a new anatomy. During the initial phases of the project, scientists focused on finding the genes responsible for C metabolism. They then added these genes to a strain of rice one at a time. In the modified rice, only about 5% of CO enters the more-efficient C pathway, says plant biologist Paul Quick at the IRRI, who led this phase of work. “We won't be able to get the benefit of the C pathway until we have the anatomy,” he says. Understanding how to build the leaf anatomy is the current phase of the project. Photosynthetic cells in the leaves of C plants are arranged around the veins in a circular pattern called Kranz anatomy (see 'Shape of things to come'). Instead of using rubisco, bundle sheath cells in this ring use the enzyme phosphoenolpyruvate carboxylase, which doesn't bind oxygen, to capture CO in a four-carbon compound. The compound is then shuttled into a second type of cell, called a mesophyll, where it is converted back to CO and fixed by rubisco. The CO concentration is much higher in C mesophyll cells, and so the rate of photorespiration is much lower. Despite the additional conversion steps and the need to move compounds between cells, this process is more efficient than C photosynthesis. To build Kranz anatomy into rice leaves, plant biologists need a developmental map. They don't know what sets a plant cell on the path to becoming part of a vein, a mesophyll or bundle sheath cell, and they don't know how these cells form the spatial patterns typical of C plants. Langdale has been studying development in maize, because it's one of only a few plants with both C leaves (the blades around the corn cob) and C leaves (all the rest). By examining the differences in gene-expression patterns between these leaf types, Langdale has found about 280 genes that seem to be involved in the formation of this Kranz anatomy. After whittling down the list to 70, based on function, her group “took each gene and put it into rice with a promoter to switch it on all the time”, she explains. Not all of the genes seemed to have an effect. Langdale is now doing further studies of ten or so of the genes that seem the most promising. Genetic engineering has advanced substantially since the C Rice Project started. Researchers used to have to transform rice one gene at a time, now they can do two or three genes at once. Eventually, they expect to be able to build a C shuttle — a set of genes required for C photosynthesis that can be inserted into various plants in one go. But first they must work out what changes to make. Langdale estimates that, realistically, C rice won't make an appearance in farmers' fields until at least 2039. In the past, improving yields through photosynthetic interventions was not a practical research focus — these were “intellectual questions”, says Christine Raines, a plant scientist at the University of Essex in Colchester, UK. Now the idea is in vogue, and researchers have the funding to test their ideas. “We will begin to see a lot of papers coming out in the next 18 months,” she says. But significant challenges lie ahead. “Organisms resist attempts to reprogram them,” says Melis, and these projects seek to alter the very heart of a plant's chemistry. Before they can make such unprecedented changes, scientists will need, for example, to better understand how resources such as sugars and lipids are routed to certain places in plant cells. Although this will be difficult, many plant biologists think that engineering photosynthesis could be the best hope for feeding a growing population and combating food insecurity. “Photosynthesis is the last big unexplored route to improving yields,” says Harbinson.
News Article | May 4, 2017
Pamela Ronald stands in front of two rows of rice plants, sprouting from black plastic pots, in a stifling greenhouse on the edge of the University of California, Davis, campus. Researchers in Ronald's plant genetics lab starved the grasses of water for more than a week. The ones on the right, the control in the ongoing experiment, are yellowing and collapsing. The leaves in the adjacent plants, equipped with an added gene, are thick, tall, and green. The hope is that these or similar genetic alterations could help rice and other crops survive devastating droughts, preventing food shortages in some of the poorest parts of the world. Ronald, a trim scientist with short brown hair, smiles as she looks down at the early results. She has spent the last three decades working to make rice, a food staple for more than half of the world's population, more resistant to environmental stress. She was a central player in one the greatest recent success stories in plant genetics, isolating a gene that allows rice to survive extended periods of flooding. It’s a huge challenge in low-lying parts of Asia, wiping out around four million tons of rice each year in India and Bangladesh alone. A decade after her lab’s discovery, more than five million farmers grow rice varieties engineered with the so-called Sub1 gene, covering more than two million hectares across Asia. The latest research could be even more significant, as climate change ratchets up the frequency and intensity of droughts across large swaths of the Earth, threatening the food security and stability of entire nations. The number of extreme droughts could double by the end of the century, devastating fields and farmers across South Asia and sub-Saharan Africa. Ronald's work provides a powerful statement for the potential of modern genetic tools to preserve livelihoods and lives, offering a counter narrative to the widespread fears and distortions surrounding genetically modified crops (see “Why We Will Need Genetically Modified Foods”). “This focus on genes in our food is a distraction from the really, really important issues,” she says. “How can we reduce the use of toxic inputs? How can we feed the poor and malnourished? How can we be sure that farmers have access to seeds, and that consumers can afford the food that’s produced?” Ronald grew up San Mateo, California. Her mother was a talented gardener and cook. Her father was a businessman who fled Nazi Germany as a child. Years after arriving in California, he built a 500-square-foot cabin in south Lake Tahoe, where the family spent summer vacations. One hot day when she was around 15, Ronald and her brothers hiked a steep path into the High Sierra. At the saddle, they happened upon a couple hovered over a book. They were a pair of professional botanists who were cataloguing flowers. She had developed an affection for plants from the time she spent with her mother in the garden and kitchen, but this was the first time she realized you could make a living working with them. In the late 1980s, during her PhD program at UC Berkeley, Ronald started working with peppers and tomatoes. But as she began her postdoctoral work, she decided to shift her focus to rice, realizing that even small advances in stress tolerance for such a critical crop could help a lot of people. Tomatoes and peppers are “important for salad, but I wanted to work on supper,” she says. “I wanted to work on a staple food crop, I wanted to move to something more important.” Ronald arrived at UC Davis as an assistant professor in 1992. Her small, square office carries signs of the work she’s done since, including Asian tapestries, illustrations and covers from journal articles, and arrayed copies of "Tomorrow's Table: Organic Farming, Genetics, and the Future of Food," the 2008 book she co-wrote with her husband, Raoul Adamchak, who teaches organic farming at UC Davis. Ronald’s work on flood-tolerant rice started in the mid-1990s, as a U.S. Department of Agriculture-funded collaboration with colleagues at UC Davis. Over the course of a decade, the team pinpointed and isolated the Sub1 gene in an ancient but unpopular Indian rice variety, known as landrace, that enables it to survive even when it was submerged under water for more than two weeks. Since then, the Philippines-based International Rice Research Institute, backed by more than $70 million in funding from the Bill and Melinda Gates Foundation, has bred that gene into 10 popular Asian rice varieties. In turn, the nonprofit put the seeds into the hands of farmers in India, Bangladesh, Indonesia, Nepal, and other nations. Rice is a tough crop to grow, requiring a lot of work and a lot of water. Too much all at once kills it, but so does too little. It takes just a week without rain to significantly decrease yields in hilly rice-growing areas. The challenges of rice production are only bound to get worse in many areas, as climate change raises temperatures, reduces rainfall in certain places, and increases flooding or sea level rise in others. Under a high greenhouse gas emissions scenario, rice yields would be nearly 15 percent lower than otherwise expected at midcentury, and prices would be 30 percent higher, according to a 2015 report in Environmental Research Letters. Shifting farming practices and the fertilizing effect of increased carbon dioxide could offset some of these climate impacts. But it’s going to become much harder and more expensive to maintain yields in many areas, and rich nations will have far greater capabilities than poor ones to make the necessary changes, says Keith Wiebe, senior research fellow at the International Food Policy Research Institute. Crops altered to survive harsher environmental conditions will be a crucial tool for helping “small farmers who produce in the more tropical environments, who will be the most exposed to climate shocks,” says Alain de Janvry, a UC Berkeley economist. The work at Ronald’s lab on drought-tolerant rice varieties is in an early phase. She declines to discuss details, including the basic approach, until they’ve conducted additional experiments to verify the initial results and published their findings. Other scientists around the world are also racing to develop drought-resistant crops, and have already achieved some advances, including sprays, hybrids, and genetic alterations that help crops switch into water-preserving modes at earlier signs of trouble, or otherwise enable plants to get by with less moisture. But greater advances will be required to confront the growing challenges ahead, and drought tolerance is a tricky problem. The trait generally involves various genes and cellular communication pathways. It’s crucial that any improvements not come at the expense of yield, taste, and other qualities important to farmers and consumers. And there would seem to be hard limits on how much can ever be achieved, as all plants need water. On an overcast Saturday in late April, Ronald stood on stage at a brick plaza on the edge of the San Francisco Bay, addressing the sign-wielding crowd gathered for the March for Science. “Science is based on data, not on alternative facts,” she said, pausing for applause at the end of most sentences. “Science is not a buffet where people can pick and choose the parts they like, and throw out the rest.” But people do, of course. The weakest applause line of her speech before the crowd, gathered largely to protest the Trump administration’s denial of climate science, was when she said that science had improved California’s fruits, vegetables, and nuts. In other words, when she took a moment to acknowledge a field that could help address some of the problems arising from a changing climate. It was typical Ronald, determined to assert where she believes the science leads, whomever the audience. Genetically modified crops have become incredibly contentious, widely portrayed as reckless attempts to tinker with Mother Nature for the sole benefit of seed conglomerates. But Ronald argues the body of science shows they’ve been both safe and beneficial. She publicly sparred with the Union of Concerned Scientists on these issues, suggested Greenpeace was “misinterpreting data,” and criticized Vermont’s GMO labeling laws in these pages (see “How Scare Tactics on GMO Foods Hurt Everybody”). Taking on the role of public face for the field has, of course, earned her critics. GMOWatch called her a “GMO propagandist,” and reveled in highlighting that her lab retracted a pair of papers in 2013, due to mislabeled bacterial strains and a faulty test. (Others praised the lab for discovering their own error, and taking pains to correct the record.) The gravest concerns over GMOs center on transgenic plants, such as the soybeans or corn engineered with a foreign bacterial gene that allowed for the use of Monsanto’s Roundup herbicide. But Ronald’s research highlights the broader definition and promise for genetic alterations. Sub1 rice sidestepped any anti-GMO backlash because, while it required the tools of modern genetics to isolate and express the gene, it doesn’t carry along any non-rice DNA. The trait from one rice variety was added to others through modern breeding methods, accelerated by analyzing the DNA of offspring to avoid false paths. Ronald notes that every major food crop has been altered by human hands in one way or another. And some of the most important advances in the future, to improve yields, nutrition, environmental tolerance, or biofuels, may be possible only with increasingly powerful gene-editing technologies such as TALENs and CRISPR. What should matter to lawmakers, regulators, or critics isn’t which implement was pulled from the ever-advancing genetic toolbox, but whether it produced a positive or negative impact on human health or the environment. At this point, we have a four-decade track record of genetic engineering in plants, medicine, and cheese, with no evidence of harm, Ronald says. The danger is that unfounded fears could come at the expense of easing real human suffering, if misguided regulations slow down the science, or protests prevent seeds and crops from reaching the farmers and consumers who need them most. For Ronald, the real goal should be sustainability in the broadest sense, applying whatever combination of breeding, organic farming, or genetic technology helps us feed a growing population without exacting a higher environmental cost. “We need to make policy based on evidence, and based on a broader understanding of agriculture,” Ronald says. “There are real challenges for farmers, and we need to be united in using all appropriate technologies to tackle these challenges.”
Chauhan B.S.,International Rice Research Institute
Crop Protection | Year: 2013
Weedy rice, an emerging problem in Asia, increases production costs and reduces farmers' income through yield reduction and through lowered rice value at harvest. Rice farmers in many Asian countries are shifting from transplanting to direct seeding; however, due to physical and physiological similarities of weedy rice to cultivated rice and the absence of standing water at the time of crop emergence, adoption of direct-seeded rice systems makes weedy rice infestation one of the most serious problems. Selective herbicides to control weedy rice in conventional rice cultivars are not available and therefore managing weedy rice is a challenging and increasing problem for farmers in Asia. In the absence of selective herbicides, various cultural weed management strategies may help reduce the problem of weedy rice. These strategies may include the use of clean seeds and machinery, use of stale seedbed practice, thorough land preparation, rotation of different rice establishment methods, use of high seeding rate and row-seeded crop, use of purple-coloured cultivars, use of flooding, and adoption of crop rotation. © 2013 Elsevier Ltd.
Chauhan B.S.,International Rice Research Institute
Weed Technology | Year: 2012
Rice is a principal source of food for more than half of the world population, and more than 90% of rice worldwide is grown and consumed in Asia. A change in establishment method from manual transplanting of rice seedlings to dry-seeded rice (DSR) has occurred in some countries as growers respond to increased costs or decreased availability of labor or water. However, weeds are a major constraint to DSR production because of the absence of the size differential between the crop and the weeds and the suppressive effect of standing water on weed growth at crop establishment. Herbicides are used to control weeds in DSR, but because of concerns about the evolution of herbicide resistance and a scarcity of new and effective herbicides, there is a need to integrate other weed management strategies with herbicide use. In addition, because of the variability in the growth habit of weeds, any single method of weed control cannot provide effective and season-long control in DSR. Various weed management approaches need to be integrated to achieve effective, sustainable, and long-term weed control in DSR. These approaches may include tillage systems; the use of crop residue; the use of weed-competitive cultivars with high-yield potential; appropriate water depth and duration; appropriate agronomic practices, such as row spacing and seeding rates; manual or mechanical weeding; and appropriate herbicide timing, rotation, and combination. This article aims to provide a logical perspective of what can be done to improve weed management strategies in DSR. © 2012 Weed Science Society of America.
Von Caemmerer S.,Australian National University |
Quick W.P.,International Rice Research Institute |
Quick W.P.,University of Sheffield |
Science | Year: 2012
Another "green revolution" is needed for crop yields to meet demands for food. The international C4 Rice Consortium is working toward introducing a higher-capacity photosynthetic mechanism - the C 4 pathway - into rice to increase yield. The goal is to identify the genes necessary to install C4 photosynthesis in rice through different approaches, including genomic and transcriptional sequence comparisons and mutant screening.
Agency: GTR | Branch: BBSRC | Program: | Phase: Research Grant | Award Amount: 266.43K | Year: 2012
Zinc (Zn) is an essential nutrient in micro-quantities for all living organisms. Deficiencies limit crop production in many parts of the world, and Zn is often deficient in the diet of humans subsisting on staple-food crops, causing severe health problems. An important strategy for dealing with this is to breed crops that are efficient in taking up Zn and concentrating it in edible plant parts. Rice is one of the main crops being targeted because of its global importance and the prevalence of Zn deficiency in populations subsisting on rice. However rice is unusual in its Zn relations compared with other cereals in two respects. First, it is mainly grown in submerged soils, and because of the peculiar biogeochemistry of submerged soils, Zn deficiency in the crop is widespread, affecting up to 50% of rice soils globally. Second, as a result of inherent physiological differences, little Zn is remobilized from existing plant reserves to grains during the grain filling growth stages, as in other cereals, so that Zn uptake appears to be one of the main bottlenecks limiting rice grain Zn contents. Research has shown that grain Zn concentrations in rice - already low compared with other cereals or pulses - are further reduced in Zn deficient soils, and large fertilizer additions are needed to overcome this. Dietary and crop Zn deficiency are inevitably linked in areas with low Zn soils, as in most parts of Asia where rice is the staple. Enhancing the Zn uptake capacity of rice varieties will therefore be crucial to increasing grain contents. It will also be important to understand long-term sustainability of growing high grain Zn rice under inherently Zn-limited conditions, and what can be done to avoid problems in the future. Current research at the International Rice Research Institute (IRRI) is using classical plant breeding combined with molecular biological markers for useful plant traits to develop rice varieties with high grain Zn contents and improved yields on Zn-deficient soils. Research is also underway to enhance grain Zn through agronomic means, including fertilizer and water management. However progress in these activities, and in understanding long-term sustainability issues, is constrained by our poor understanding of the mechanisms underlying genotype differences, and of the dynamics of plant-available Zn in the soil within the growing season and longer term. In recent research by members of the project team, we have shown that three key mechanisms enhance growth of rice seedlings in Zn deficient soil: (a) secretion from roots of Zn-chelating compounds called phytosiderophores and subsequent uptake of chelated Zn in the rhizosphere, (b) maintenance of new root growth, and (c) prevention of root damage by oxygen radicals linked to high bicarbonate concentrations. Studies with a limited set of genotypes suggest that Zn loaded into grains mostly comes from Zn uptake during the reproductive stages rather than by re-translocation from vegetative tissue. The mechanisms listed above in relation to seedling growth may also assure adequate Zn uptake during the reproductive phase. However, this has not been systematically investigated so far, nor have any genes related to reproductive-stage Zn uptake been tagged. The proposed research addresses these knowledge gaps with an interdisciplinary approach linking fundamental research on soil biogeochemistry, molecular physiology and genetics with applied work on agronomy and plant breeding, with a conceptual framework provided by mathematical modelling. Our goal is to develop genotypes and management practices for growing high Zn rice in Zn deficient soils, suitable for resource-poor farmers. This will encompass agronomic interventions based on understanding of limiting factors for Zn uptake and translocation, and breeding approaches based on understanding of genetic factors controlling key tolerance mechanisms.
International Rice Research Institute | Date: 2014-12-11
The present invention provides methods and materials useful for improving early vigor of plants during germination. The methods and materials described herein are useful for improving early vigor of plants grown under either aerobic or anaerobic conditions. In particular embodiments described herein, the methods and materials described herein are useful for improving anaerobic germination of plants.
International Rice Research Institute and Japan International Research Center For Agricultural Science | Date: 2014-04-28
Described herein are methods and materials useful for improving root growth and nutrient uptake in cereal grasses. In particular, present disclosure provides methods for increasing root growth and nutrient uptake in a cereal grass involving marker assisted selection and backcrossing. The present disclosure also provides recombinant DNA for the generation of transgenic plants, transgenic plant cells, and methods of producing the same. The present disclosure also provides materials and methods useful for improving the tolerance of a cereal grass to phosphorus-deficiency The present disclosure further provides methods for generating transgenic seed that can be used to produce a transgenic plant having increased root growth, nutrient uptake, and phosphorus-deficiency tolerance.
International Rice Research Institute | Date: 2014-10-08
Described herein are methods and materials useful for improving lateral root growth, water uptake, and the yield of grain of cereal grasses grown under drought stress conditions. In particular, the present disclosure provides a quantitative trait locus associated with improved yield under drought stress. The disclosure further provides recombinant DNA for the generation of transgenic plants, transgenic plant cells, and methods of producing the same. The present disclosure further provides methods for generating transgenic seed that can be used to produce a transgenic plant having improved yield under drought stress, and methods for improving yield under drought stress in a cereal grass involving marker assisted selection and backcrossing.
Agency: European Commission | Branch: FP7 | Program: CP-TP | Phase: KBBE.2011.3.1-01 | Award Amount: 8.94M | Year: 2012
Most plants use the C3 pathway of photosynthesis that is compromised by gross inefficiencies in CO2 fixation. However, some plants use a super-charged photosynthetic mechanism called C4 photosynthesis. The C4 pathway is used by the most productive vegetation and crops on Earth. In addition to faster photosynthesis, C4 plants demand less water and less nitrogen. Overall, our aim is to introduce the characteristics of C4 into C3 crops. This would increase yield, reduce land area needed for cultivation, decrease irrigation, and limit fertiliser applications. If current C3 crops could be converted to use C4 photosynthesis, large economic and environmental benefits would ensue from both their increased productivity and the reduced inputs associated with the C4 pathway. It is important to note that the huge advances in agricultural production associated with the Green Revolution were not associated with increases in photosynthesis, and so its manipulation remains an unexplored target for crop improvement both for food and biomass. Even partial long-term success would have significant economic and environmental benefits. Efficient C4 photosynthesis would be achieved by alterations to leaf development, cell biology and biochemistry. Although initially we will be using model species such as rice and Arabidopsis we envisage rapid transfer of technological advances into mainstream EU crops, such as wheat and rape, that are used both for food and fuel. We will build capacity for C4 research in Europe in this area by the training of future generations of researchers. To achieve this aim we need to increase our understanding of the basic biology underlying the C4 pathway. Our specific objectives will therefore address fundamental aspects of C4 biology that are needed for a full understanding the pathway. Specifically we aim: 1. To understand the roles and development of the two cell types (mesophyll and bundle sheath) in C4 plants. 2. To identify mechanisms controlling the ex