Manipulation of Host Signaling by Pathogens
Mellgren, Eve M , Laurie-Berry, Neva , Demianski, Agnes J , Kunkel, Barbara N .
Coronatine, a Pseudomonas syringae phytohormone mimic, modulates multiple aspects of host biology to promote disease.
We are interested in the mechanisms by which plant pathogens modulate normal host cell processes to promote tissue colonization and disease development. Successful pathogen infection involves entry into host tissue, suppression of general antimicrobial host defenses, and growth to high levels in the plant. The phytotoxin coronatine (COR), a virulence factor of the bacterial plant pathogen Pseudomonas syringae, plays a key role in these events. COR biosynthetic (COR-) mutants of P. syringae strain DC3000 do not multiply to high levels or cause disease on Arabidopsis and tomato. COR is required at multiple steps during P. syringae pathogenesis, including: 1) entry into host tissue, 2) suppression of salicylic acid (SA)-mediated defenses subsequent to entry, and 3) promotion of disease symptom development. COR is a functional analog of the endogenous plant hormone jasmonic acid (JA), most closely resembling the JA amino acid conjugate JA-isoleucine. Molecular and genetic studies indicate that COR stimulates JA signaling during P. syringae infection, and that an intact JA signaling pathway is required for full susceptibility to P. syringae in both Arabidopsis and tomato. We are interested in further elucidating the roles of COR and JA-mediated processes in P. syringae pathogenesis, and are focusing on the AtMyc2/JIN1-mediated branch of the JA signaling pathway required for susceptibility to P. syringae. This includes utilizing a combination of forward and reverse genetic approaches to identify and characterize novel JA signaling components and to investigate their roles during pathogenesis of Arabidopsis.
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1 - Washington University, Department of Biology, Campus Box 1137, 1 Brookings Drive, St Louis, MO, 63130, USA
Presentation Type: ASPB Major Symposium
Location: International Ballroom/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:30 AM