Laurie-Berry, Neva , Kunkel, Barbara N .
Identification of two novel arabidopsis mutants with hypersensitivity to jasmonic acid and the Pseudomonas syringae phytotoxin coronatine.
Many plant pathogens are proposed to suppress basic antimicrobial defenses using secreted virulence factors that modulate endogenous host defense signaling pathways. The Pseudomonas syringae phytotoxin coronatine (COR) is believed to promote virulence by acting as a molecular mimic of one or more jasmonates, such as JA-Ile. This model is supported by several jasmonate signaling mutants in arabidopsis (e.g. coi1, jin1, axr1) and tomato (jai1/coi1) with decreased sensitivity to COR and reduced susceptibility to P. syringae infection. To further investigate the signaling pathway manipulated by COR during the disease process, we conducted a screen for novel mutants with altered sensitivity to COR. Over 23,000 seedlings were screened, and seven were identified with altered sensitivity to COR. Four of these were insensitive and determined to be alleles of known genes: coi1, jin1, and axr1. The remaining three mutants exhibited hypersensitivity to COR and MeJA. Two of these mutants do not exhibit growth patterns indicative of constitutive jasmonate signaling, a novel phenotype that suggests these mutants represent previously unidentified components of jasmonate signaling. Further characterization of these two mutants is underway, including assaying disease susceptibility, monitoring expression of jasmonate-responsive genes, and mapping of one of these mutants to identify the affected gene.
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1 - Washington University, Department of Biology, Campus Box 1137, 1 Brookings Drive, St Louis, MO, 63130, USA
2 - Washington University, Department of Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM