March 25, 2021
Barbara Valent to present Division of Biology Seminar
Barbara Valent, university distinguished professor of plant pathology, Interdepartmental Genetics Program Chair, Kansas State University, will present "Genome dynamics of Magnaporthe oryzae, a global threat to rice and wheat production" as part of the Division of Biology Seminar Series at 3:30 p.m. Monday, March 29, via Zoom.
The filamentous fungus Magnaporthe oryzae includes pathogens of more than 50 grass species, including distinct lineages causing the ancient rice blast disease, dating from ~7000 years ago in China, and the emerging wheat blast disease, first reported in Brazil in 1985. Our work focuses on biology of pathogen effectors, which are small unique proteins that play key roles in both the pathogen's ability to cause disease and also in a plant’s ability to resist disease. First, we use molecular genetics and live-cell microscopy to understand the specialized protein secretion and membrane translocation mechanisms used by the blast fungus to flood living host cells with hundreds of effector proteins to block defenses and prepare the tissue for infection. Second, we have focused on understanding how the blast fungus so quickly overcomes resistance deployed in the field to control it. Specifically, plant resistance genes encode receptors that recognize individual effectors, called avirulence, or AVR, effectors. Recognition triggers resistance and blocks disease. Genomic features associated with the rapid fungal response to defeat deployed resistance include deletion of the gene encoding the recognized AVR effector, and dramatically different genomic locations of AVR genes in different fungal field isolates. We have shown that mobile effector genes reside in a fast-evolving fungal genome compartment featuring DNA sequence exchanges between the ends of core chromosomes and dispensable supernumerary chromosomes present in some strains of the fungus. Impact of these findings on disease control will be discussed.
If you would like to visit with Valent, please contact Govind Vediyappan at firstname.lastname@example.org.