Pathogen virulence proteins suppress plant immunityApril 22, 2008Blacksburg, Va. - Researchers from the Virginia Bioinformatics Institute (VBI) at Virginia Tech and their colleagues have identified a key function of a large family of virulence proteins that play an important role in the production of infectious disease by the plant pathogen Phytophthora sojae. VBI Professor Brett Tyler and members of his research group, along with researchers from Virginia Tech's Department of Plant Pathology, Physiology and Weed Science, Nanjing Agricultural University in China, and Wageningen University in The Netherlands, examined the function of the virulence (or effector) protein Avr1b in P. sojae and discovered that Avr1b is capable of suppressing an important process in plant immunity called programmed cell death. Programmed cell death is an in-built suicide mechanism that kills infected plant tissue and fills it with toxins so the pathogen can no longer feed on it. The work appears in the advance online edition of The Plant Cell. (1) P. sojae is an oomycete plant pathogen that causes severe damage to soybean crops, resulting in $1-2 million in annual losses for commercial farmers in the United States and much more worldwide. By changing key amino acid residues in the effector protein, the researchers were able to attribute the cause of the suppression of programmed cell death to the presence of two conserved sequences (dubbed W and Y motifs) at one particular end of the protein, the C-terminus. These amino acid sequences are also present in many other members of a huge virulence gene superfamily that Tyler's group found recently in oomycete pathogens. (2) According to VBI Professor Brett Tyler, "Our results suggest that, like many human viruses such as HIV, oomycete plant pathogens disable the immune systems of their victims as part of their infection strategy." ### The research was supported by funding from the National Research Initiative of the United States Department of Agriculture's Cooperative State Research, Education and Extension Service, the National Science Foundation, the Government of China, and the Netherlands Genomics Initiative. (1) Daolong D, Kale SD, Wang X, Chen Y, Wang Q, Wang X, Jiang RHY, Arredondo FD, Anderson RG, Thakur PB, McDowell JM, Wang Y, Tyler BM (2008) Conserved C-terminal motifs required for avirulence and suppression of cell death by Phytophthora sojae effector Avr1b. The Plant Cell Published on April 4, 2008; 10.1105/tpc.107.057067. (2) Jiang R, Tripathy S, Govers F, Tyler BM (2008) RXLR effector reservoir in two Phytophthora species is dominated by a single rapidly evolving superfamily with more than 700 members. Proc. Natl Acad. Sci. USA 105(12): 4874-4879. Virginia Tech |
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| Related Phytophthora Current Events and Phytophthora News Articles Does hotter mean healthier? Phytophthora blight, caused by Phytophthora capsici, is a major plant disease that affects many crop species worldwide, including chile peppers in New Mexico. Farmers' observations suggested that Phytophthora capsici caused less damage in pepper crops of the hot pepper varieties than low-heat pepper varieties. DOE Joint Genome Institute completes soybean genome The U.S. Department of Energy Joint Genome Institute (DOE JGI) has released a complete draft assembly of the soybean (Glycine max) genetic code, making it widely available to the research community to advance new breeding strategies for one of the world's most valuable plant commodities. Key to virulence protein entry into host cells discovered Researchers from the Virginia Bioinformatics Institute (VBI) at Virginia Tech have identified the region of a large family of virulence proteins in oomycete plant pathogens that enables the proteins to enter the cells of their hosts. Huge virulence gene superfamily responsible for devastating plant diseases A research team from the Virginia Bioinformatics Institute at Virginia Tech has identified an enormous superfamily of pathogen genes involved in the infection of plants. Challenges remain in reintroducing American chestnut Researchers have developed a breed of American chestnut that is resistant to the fungal blight that decimated its population in the early 1900s. Humans fostering forest-destroying disease Enjoying your August vacation? Well, (as they say in the summer movies) there's a killer in the woods. Its strike has been consistently quiet, sudden, and deadly. Californians urged to help reduce spread of Sudden Oak Death An update on the increased spread of Sudden Oak Death, a plant disease devastating many of California's coastal oak and tanoak trees, and information on what Californians can do to help reduce its spread will be presented during a news conference on plant diseases that are of importance to California's economy and agriculture. Scientists expand microbe 'gene language' An international group of scientists has expanded the universal language for the genes of both disease-causing and beneficial microbes and their hosts. Genome info from 'plant destroyers' could save trees, beans and chocolate An international team of scientists has published the first two genome sequences from a destructive group of plant pathogens called Phytophthora-a name that literally means "plant destroyer." Sequences reveal benign origin of deadly plant pathogens An international team of researchers has published the draft genome sequences of two deadly plant pathogens, Phytophthora ramorum and Phytophthora sojae. More Phytophthora Current Events and Phytophthora News Articles |
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