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NIFA-Supported Research at Virginia Tech Leads to Greater Understanding of Downy Mildew Disease

Media Contact: Jennifer Martin, (202) 720-8188

WASHINGTON, Dec. 9, 2010 – An international team of scientists, who received partial funding from USDA’s National Institute of Food and Agriculture (NIFA), have mapped the genome of the plant pathogen that causes downy mildew disease, which cause major losses to crops such as corn, grapes and lettuce.

The genome sequence of Hyaloperonospora arabidopsidis, the pathogen that causes downy mildew disease, is published this week in the journal Science. In the paper, researchers compare the sequence of H. arabidopsidis with other fully sequenced genomes of destructive plant pathogens to shed light on the differences in the ways microbes interact with their host and how those differences evolve. The study could lead to new ways to investigate how these pathogens cause plant disease and find new ways to prevent plant loss in the future.

H. arabidopsidis is dependent on the plant it attacks and can’t survive away from it. By comparing the genome sequence of H. arabidopsidis with its close cousin¸ Phytophthora ramorum, which is the pathogen responsible for Sudden Oak Death, the researchers revealed a massive loss of genes related to H. arabidopsidis’s plant-dependent lifestyle.

The genome sequence of H. arabidopsidis shows large number of effector proteins, which are used to invade plant cells and a reduction in the number of genes related to degradative enzymes and other molecules linked to the metabolism of nitrogen and sulfur. This suggests H. arabidopsidis has dispensed with many genes required for life away from the plant, instead focusing on genes that help it take control of host plants. The gene loss provides many clues on the evolutionary adaptation necessary for a pathogen to become fully dependent on a plant host. This revelation made in the comparison to the P. ramorum genome sequence will allow scientists to zero in on common genes to create more effective downy mildew disease control strategies.

The project was a collaboration involving scientists at Virginia Tech, Washington University, the Sainsbury Laboratory, the Sequencing Center at the Wellcome Trust Sanger Institute and the University of Warwick. NIFA funded this project with a grant to the Virginia Bioinformatics Institute at Virginia Tech through the Microbial Genomics program of the Agriculture and Food Research Initiative. In addition to funding provided by NIFA, the work was supported by the Emerging Frontiers program of the National Science Foundation.

Through federal funding and leadership for research, education and extension programs, NIFA focuses on investing in science and solving critical issues impacting people's daily lives and the nation's future.  More information is at:


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