Researchers successfully simulate photosynthesis and design a better leafNovember 12, 2007CHAMPAIGN, Ill. - University of Illinois researchers have built a better plant, one that produces more leaves and fruit without needing extra fertilizer. The researchers accomplished the feat using a computer model that mimics the process of evolution. Theirs is the first model to simulate every step of the photosynthetic process. The research findings appear in the October issue of Plant Physiology, and will be presented today at the BIO-Asia 2007 Conference in Bangkok, Thailand. The research was sponsored by the National Science Foundation. Photosynthesis converts light energy into chemical energy in plants, algae, phytoplankton and some species of bacteria and archaea. Photosynthesis in plants involves an elaborate array of chemical reactions requiring dozens of protein enzymes and other chemical components. Most photosynthesis occurs in a plant's leaves. "The question we wanted to ask, was, 'Can we do better than the plant, in terms of productivity?' " said principal investigator Steve Long, a professor of plant biology and crop sciences at the University of Illinois. It wasn't feasible to tackle this question with experiments on actual plants, Long said. With more than 100 proteins involved in photosynthesis, testing one protein at a time would require an enormous investment of time and money. "But now that we have the photosynthetic process 'in silico,' we can test all possible permutations on the supercomputer," he said. The researchers first had to build a reliable model of photosynthesis, one that would accurately mimic the photosynthetic response to changes in the environment. This formidable task relied on the computational resources available at the National Center for Supercomputing Applications. Xin-Guang Zhu, a research scientist at the center and in plant biology, worked with Long and Eric de Sturler, formerly a specialist in computational mathematics in computer sciences at Illinois, to realize this model. After determining the relative abundance of each of the proteins involved in photosynthesis, the researchers created a series of linked differential equations, each mimicking a single photosynthetic step. The team tested and adjusted the model until it successfully predicted the outcome of experiments conducted on real leaves, including their dynamic response to environmental variation. The researchers then programmed the model to randomly alter levels of individual enzymes in the photosynthetic process. Before a crop plant, like wheat, produces grain, most of the nitrogen it takes in goes into the photosynthetic proteins of its leaves. Knowing that it was undesirable to add more nitrogen to the plants, Long said, the researchers asked a simple question: "Can we do a better job than the plant in the way this fixed amount of nitrogen is invested in the different photosynthetic proteins?" Using "evolutionary algorithms," which mimic evolution by selecting for desirable traits, the model hunted for enzymes that - if increased - would enhance plant productivity. If higher concentrations of an enzyme relative to others improved photosynthetic efficiency, the model used the results of that experiment as a parent for the next generation of tests. This process identified several proteins that could, if present in higher concentrations relative to others, greatly enhance the productivity of the plant. The new findings are consistent with results from other researchers, who found that increases in one of these proteins in transgenic plants increased productivity. "By rearranging the investment of nitrogen, we could almost double efficiency," Long said. An obvious question that stems from the research is why plant productivity can be increased so much, Long said. Why haven't plants already evolved to be as efficient as possible? "The answer may lie in the fact that evolution selects for survival and fecundity, while we were selecting for increased productivity," he said. The changes suggested in the model might undermine the survival of a plant living in the wild, he said, "but our analyses suggest they will be viable in the farmer's field." Long also is the deputy director of the Energy Biosciences Institute and an affiliate of the Institute for Genomic Biology and the supercomputing center. University of Illinois at Urbana-Champaign |
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| Related Photosynthesis Current Events and Photosynthesis News Articles Beyond sunlight: Explorers census 17,650 ocean species between edge of darkness and black abyss Census of Marine Life scientists have inventoried an astonishing abundance, diversity and distribution of deep sea species that have never known sunlight - creatures that somehow manage a living in a frigid black world down to 5,000 meters (~3 miles) below the ocean waves. Oceans' uptake of manmade carbon may be slowing The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. UT Knoxville and ORNL researchers turn algae into high-temperature hydrogen source In the quest to make hydrogen as a clean alternative fuel source, researchers have been stymied about how to create usable hydrogen that is clean and sustainable without relying on an intensive, high-energy process that outweighs the benefits of not using petroleum to power vehicles. Antarctica glacier retreat creates new carbon dioxide store Large blooms of tiny marine plants called phytoplankton are flourishing in areas of open water left exposed by the recent and rapid melting of ice shelves and glaciers around the Antarctic Peninsula. Newly Discovered Fat Molecule: An Undersea Killer with an Upside A chemical culprit responsible for the rapid, mysterious death of phytoplankton in the North Atlantic Ocean has been found by collaborating scientists at Rutgers University and the Woods Hole Oceanographic Institution (WHOI). This same chemical may hold unexpected promise in cancer research. Chemists describe solar energy progress and challenges, including the 'artificial leaf' Scientists are making progress toward development of an "artificial leaf" that mimics a real leaf's chemical magic with photosynthesis - but instead converts sunlight and water into a liquid fuel such as methanol for cars and trucks. Toward home-brewed electricity with 'personalized solar energy' New scientific discoveries are moving society toward the era of "personalized solar energy," in which the focus of electricity production shifts from huge central generating stations to individuals in their own homes and communities. Sun or shade: Pecan leaves' photosynthetic light response evaluated Pecan, the most valuable nut tree native to North America, is native from northern Illinois and southeastern Iowa to the Gulf Coast of the United States, where it grows abundantly along the Mississippi River, the rivers of central and eastern Oklahoma, and Texas. Reflective film can boost profits for apple growers In a research report published in a recent issue of HortTechnology, scientists Ignasi Iglesias and Simó Alegre examined the effects of covering orchard floors with reflective films on fruit color, fruit quality, canopy light distribution, orchard temperature, and profitability. Iron controls patterns of nitrogen fixation in the Atlantic Scientists including researchers from the National Oceanography Centre, Southampton and the University of Essex have discovered that interactions between iron supply, transported through the atmosphere from deserts, and large-scale oceanic circulation control the availability of a crucial nutrient, nitrogen, in the Atlantic. More Photosynthesis Current Events and Photosynthesis News Articles |
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