Poster: Plant-pathogen interactions
Abs #
510: Loss-of-function mutations in the chitin responsive genes atl7 and crrp1 show increased susceptibility to the powdery mildew pathogen, Erysiphe cichoracearum.
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Presenter: |
Ramonell, Katrina M, kramonel@bama.ua.edu |
Authors | Ramonell, Katrina M (A) Berrocal-Lobo, Marta (B) Wan, Jinrong (C) Stacey, Gary (C) Somerville, Shauna (B) | | Affiliations: |
(A): University of Alabama, Department of Biological Sciences
(B): Carnegie Institution of Washington, Department of Plant Biology
(C): University of Missouri, Department of Plant Microbiology and Pathology
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Chitin oligomers induce defense-related cellular responses in plants though the exact mechanism behind this response is unknown. Previous work by our group has shown that chitin-elicited defense responses in Arabidopsis are similar to those observed in rice and soybean suggesting that Arabidopsis would be an excellent model to elucidate the mechanisms of chitin elicitation in plant defense. Using the ATH1 Affymetrix full-genome arrays consisting of 23,000 genes, we examined the response of Arabidopsis seedlings to chitin tetramers, chitin octamers and hydrolyzed crab-shell chitin after 30 minutes of treatment. Microarray analysis showed the expression responses observed in the chitin octamer and hydrolyzed crab-shell chitin treatments were very similar, however the expression profile elicited by treatment with the chitin tetramer was significantly different from the other treatments. Microarray expression profiles from several chitin responsive genes were then verified via Northern analysis. Based on data from these array experiments, we chose several Salk T-DNA insertion lines in chitin responsive genes in order to access if there were any changes in the mutants’ defense response to the powdery mildew pathogen, Erysiphe cichoracearum. Conidia growth and percent of the leaf surface infected were used to score the defense phenotype of each insertion line. Knock-out mutations in two genes, atl7 and crrp1, showed a hyper-susceptible response to powdery mildew similar to that observed in SA-compromised NahG transgenic lines. These results indicate that chitin is an important elicitor of plant defense against fungal pathogens. In addition, this study demonstrates the power of microarray data to identify potential targets for mutation in uncharacterized signaling pathways.
