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POSTERS: Molecular plant-microbe interactions

Characterization of Sclerotinia sclerotiorum isocitrate lyase gene in virulence on canola
Luis del Rio Mendoza - North Dakota State Univ. Kishore Chittem- North Dakota State University, Sudha G C Upadhaya- North Dakota State University

From differential gene expression data, genes involved in peroxisome associated pathways like fatty acid ß-oxidation and glyoxylate cycle were identified as novel potential pathogenicity candidates. The role of these pathways/genes has been shown to be essential for pathogenicity in several plant pathogens, including Leptosphaeria maculans, another important pathogen of canola. Based on these findings, isocitrate lyase (SS1G_04975 – SsICL), a key glyoxylate pathway gene was selected as candidate pathogenicity/virulence gene for functional characterization. Gene disruption mutants for SsICLwere developed by targeted gene replacement following split marker approach. PCR assays confirmed correct replacement of the gene. The effect of deletion of SsICLdid not result in significant reduction in mycelial growth on PDA or production of oxalic acid. However, SsICL deletion mutant significantly affected the ability of S. sclerotiorum to utilize oleic acid as sole source of carbon on minimal media. Pathogenicity assays on leaf inoculation indicated that SsICL is required for full virulence on canola.