MINNEAPOLIS / ST. PAUL--Two groups of plant scientists at the University of Minnesota have each received four-year, $3.1 million grants from the National Science Foundation to study the genomes of legumes and corn as part of NSF's Plant Genome Research Program. They are among 24 new grants totaling more than $71 million, which will be shared by 109 investigators at 39 institutions in 27 states. Both grants are renewals of previous NSF grants to the scientists.
The corn project is headed by Ronald Phillips, Regents Professor of Agronomy and Plant Genetics at the University of Minnesota. The university received the total award of $3,081,245. The legume project is coordinated at the university by Nevin Young, a professor of plant pathology and plant biology, and involves five other investigators at the University of Minnesota. The total award for the project is $5,803,691, of which the university received a subaward of $3,098,136. The principal investigator is Douglas Cook of the University of California-Davis. Other partners are The Institute for Genomic Research in Maryland and the Samuel Roberts Noble Foundation in Oklahoma.
The corn project will allow Phillips and his colleague Howard Rines, a U.S. Department of Agriculture scientist and adjunct professor at the University of Minnesota, to continue work on a system to map genes of the corn plant in a highly efficient manner, which will facilitate subsequent analysis of how the genes work separately and together. The grant is unusual in that no other institution is involved.
To map the genes, corn is crossed with oats. The hybrid plant often rejects all 10 corn chromosomes, but some plants retain one corn chromosome, Phillips said. Hybrids retaining each of the corn chromosomes have been produced and irradiated, which breaks the chromosomes into fragments. Hybrid plant lines with a single fragment of a corn chromosome have been produced. Scientists are "isolating corn genes left and right," said Phillips, and the chromosomal location of a given gene (or DNA sequence) can be found by testing each line for the gene's presence. This will reveal which fragment, and therefore which part of which chromosome, the gene is from.
"The corn genome has 2,500 million DNA base pairs," Phillips said. "This system theoretically lets us map to within 5 million base pairs or less. With this grant, mapping will be done enough to prove the concept and the system for future uses."
One goal is to achieve 1,000 hybrid plant lines, each essentially an oat plant with a unique fragment of a corn chromosome. Another goal is to map more than 100,000 DNA sequences with the system.
Phillips will share his data and hybrid plants with other researchers. The mapping system will aid work on how corn genes express themselves in the environment of oat cells and whether corn genes could be used to improve desirable traits in oats, both of which have application in plant genetic engineering; the evolution of the corn plant; and various aspects of corn chromosome functioning.
The legume project will focus on the barrel medic, a close relative of alfalfa that, like alfalfa and other legumes, can "fix" atmospheric nitrogen into a form plants can use as a fertilizer. The plant owes this ability to symbiosis with bacteria that infect its roots. The work will center on how the plant communicates with the bacteria, said Nevin Young, a professor of plant pathology and coordinator of the grant at the university.
"This interaction teaches us about how other organisms communicate," Young said. "For example, similar types of communication occurs between organisms living in symbiosis and between hosts and infectious agents in disease."
"Legumes are important in human and animal diets because they're protein-rich," said Kate VandenBosch, a co-investigator on the grant. "Worldwide, legumes supply 33 percent of human protein intake, and people have historically based their diets on a combination of legumes and grain. In Middle America it was beans and corn, in the Far East soybeans and rice and in Africa cowpeas and sorghum." Legumes such as peanuts and soybeans are valuable sources of oil, and legumes also contain unique "phytochemicals" like isoflavones, which seem to promote heart health. Some of the same heart-healthy compounds are also used by the plant in communicating with its symbiotic bacteria, VandenBosch said.
The barrel medic was chosen as a model legume because its genome is smaller and simpler than that of alfalfa or soybeans. The researchers will build a library of the plant's genes and study when they are turned on during the course of development and in which plant tissues. Researchers at the University of Minnesota and elsewhere are sequencing the genome, which they hope will become the third plant genome to be fully sequenced. The others were a mustard relative called Arabidopsis, followed by rice.
The barrel medic is cultivated in Mediterranean countries and Australia. It can grow in alkaline soils, dry soils and other marginal areas. By studying plants whose particular genetic makeup allows them to survive in extreme environments, the researchers hope to gain insight into how the plants deal with infection, pollutants and other stressors. Young and university colleague Ernest Retzel, an investigator on both new grants, are already studying soybean genomics. The overall goal is to translate genomic advances in the barrel medic and soybean projects to less well studied but economically important crops.
Retzel, a bioinformaticist, will direct analysis of the data generated by both projects. The data will be made available to researchers and the public.
Contacts:
Ronald Phillips, Agronomy and Plant Genetics Dept., 612-625-1213, phill005@umn.edu
Nevin Young, Plant Pathology Dept., 612-625-2225, neviny@umn.edu
Deane Morrison, University News Service, 612-624-2346, morri029@umn.edu