NSF PR 00-60

Press Release

NSF PR 00-60 - September 21, 2000

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NSF Boosts Research for Understanding Structure and Function of Complex Plant Genomes

The National Science Foundation (NSF) is providing a boost to plant biology research through 16 new grants totaling more than $48 million over the next 5 years.

The new research will contribute to a better understanding of the structure and function of all plant genes, including those from economically important crops like maize (corn), wheat and rice. According to program managers the research emphasis is on functional genomics and tools. Many of the projects will build on the research outcomes from the first two years of the Plant Genome Research Program.

"This year’s awards continue to add new and exciting dimensions to the field of plant genome research," says Mary Clutter, NSF assistant director for biological sciences. "The focus has been on functional genomics research designed to understand, at the whole genome scale, the functions of plant genes involved in such fundamental processes as chloroplast biogenesis, plant nutrition, host-pathogen interactions, and plant responses to environmental stress signals. Many of these projects make full and effective use of plant genome research infrastructure developed by the past awards. I am confident that the new awards along with the past awards will make the progress needed to meet the goals of the National Plant Genome Initiative, of which this NSF program is a part."

As scientists move from model systems to the challenges of studying the larger, more complex genomes found in economically important crops such as maize and wheat, it will be important to have specialized tools for analyzing gene structure and function, plant biologists say. For example, bread wheat has a huge genome that is a combination of the individual genomes coming from several progenitor plants. The smallest of these, known as the D genome, carries most of the important genes for bread wheat improvement. A project funded at the University of California at Davis will use a new fingerprinting method that should allow construction of a physical map of the D genome, the largest genome to be tackled to date. This part of the wheat genome alone is more than two and half times the size of the whole maize genome, and ten times the size of the whole rice genome. In addition to providing much-needed tools for wheat research, the outcomes of this project could eventually be useful for mapping genes in other large plant genomes.

An important outcome of plant genome research has been the finding that some plant genomes have undergone significant changes on a whole-genome scale during evolution. A common change is an increase in the number of chromosome copies in the nucleus, termed polyploidy. Many agriculturally important plants like maize and wheat are polyploid, and their history has had a profound impact on their genomes. The outcome of work funded at the University of Wisconsin at Madison will give the first genome wide analysis of the impact of ploidy in one model species (Arabidopsis,the mustard plant) and two crop species (brassica and maize). Other widespread agents of genomic diversity are transposable elements. About 30 percent of the new genome is thought to be derived from these small, mobile pieces of DNA. Work funded at the University of Georgia will examine the rice genome to characterize all the different families of elements present. The findings from this work should give a complete picture of the elements from rice, and point the way to characterizing this important component of other larger cereal genomes.

The development of tools such as microarrays and tagged mutants will allow scientists to begin to define the functions of many of the genes in economically important pathways and processes. New research under the latest awards funded at the University of Florida will uncover the genes involved in development of maize endosperm. Endosperm, the starchy part of maize kernels, is an important food source and also serves as a good basic model for organ development in plants. In a related project, research funded at the University of Oregon will characterize the functions of genes needed to build and maintain maize chloroplasts. Chloroplasts are the compartments in plant cells where sunlight is harvested and used to drive synthesis of sugars.

Plant pathogens also impact crop yield and basic plant growth processes,but usually in a negative way. For example, the root knot nematode worm (Meloidogyne sps.) is an important pathogen of many economically important crops such as soybean. North Carolina State University researchers will take aim at understanding the genes involved in the interaction between the nematode and the plant during the infection process. The outcome of this project has the potential to allow development of novel nematode control strategies. Research funded at Cornell University will tackle another important plant pathogen, Pseudomonas syringae pv. tomato, which causes bacterial speck disease in tomato and related plants. This research will not only increase our understanding of this specific disease, but also the basic processes common to many pathogenic interactions between plants and bacteria.

Researchers have found that many of the pathways involved in building and maintaining plants involve cascades of chemical signals known as plant hormones. If the functions of these pathways are to be fully understood, it will be necessary to gain a better understanding of plant hormones and how they work, scientists believe. Research funded at The University of Texas at Austin will test a new screen for mutations affecting the synthesis and action of one plant hormone known as auxin. While some of these genes have already been identified, this research will be the first to attempt to collect a large number of mutants with defects in all aspects of auxin biology.

For more information, see: http://www.nsf.gov/bio/pubs/awards/genome00.htm

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