ABSTRACT: The fungal pathogen Sclerotinia sclerotiorum infects a broad range of dicotyledonous plant species and is the causative agent of stem rot in Brassica napus. To elucidate the mechanisms underlying the defense response, we studied the patterns of gene expression in a partially resistant variety of ZhongYou 821 (ZY821) and a susceptible line from Westar over five time points, 6, 12, 24, 48, and 72 hours post-inoculation (hpi) using a B. napus oligonucleotide microarray. Maximum differential gene expression was observed at 48 hpi in both genotypes with ZY821 responding more quickly than Westar. Specific sets of genes exhibited higher levels of expression at the earlier stages of the infection (6-12 hpi), including genes encoding defense-associated proteins such as chitinases, glucanases, osmotins and lectins and genes encoding transcription factors belonging to the zinc finger, WRKY, AP2, and MYB classes. Genes encoding enzymes involved in JA, ethylene, and auxin synthesis were induced in both genotypes, as were those for gibberellin degradation. Changes in metabolic pathways affecting carbohydrate and energy metabolism appeared to be directed toward shuttling carbon reserves to the TCA cycle. Genes involved in glucosinolate and phenylpropanoid biosynthesis were highly up-regulated suggesting that secondary metabolites are also important components of the response to S. sclerotiorum in B. napus. Keywords: Time course, and infected vs mock infected Time course experiment (6hr, 12 hr, 24 hr, 48 hr, 72 hrs), sclerotinia infected vs mock-infected. Biological replicates: 3, independently harvested. Technical replicates: 2, dye swapped within each time for each biological replicate (total 6 slides per time point) time after innoculation: 6 hours: westar 6h inf vs control rep1, westar 6h control vs inf rep1, westar 6h inf vs control rep2, westar 6h control vs inf rep2, westar 6h inf vs control rep3, westar 6h control vs inf rep3 time after innoculation: 12 hours: westar 12h inf vs control rep1, westar 12h control vs inf rep1, westar 12h inf vs control rep2, westar 12h control vs inf rep2, westar 12h inf vs control rep3, westar 12h control vs inf rep3 time after innoculation: 24 hours: westar 24h inf vs control rep1, westar 24h control vs inf rep1, westar 24h inf vs control rep2, westar 24h control vs inf rep2, westar 24h inf vs control rep3, westar 24h control vs inf rep3 time after innoculation: 48 hours: westar 48h inf vs control rep1, westar 48h control vs inf rep1, westar 48h inf vs control rep2, westar 48h control vs inf rep2, westar 48h inf vs control rep3, westar 48h control vs inf rep3 time after innoculation: 72 hours: westar 72h inf vs control rep1, westar 72h control vs inf rep1, westar 72h inf vs control rep2, westar 72h control vs inf rep2, westar 72h inf vs control rep3, westar 72h control vs inf rep3 biological replicate: westar 6h inf vs control rep1, westar 6h inf vs control rep2, westar 6h inf vs control rep3 biological replicate: westar 6h control vs inf rep1, westar 6h control vs inf rep2, westar 6h control vs inf rep3 technical replicate - labeled-extract: westar 6h inf vs control rep1, westar 6h control vs inf rep1 technical replicate - labeled-extract: westar 6h inf vs control rep2, westar 6h control vs inf rep2 technical replicate - labeled-extract: westar 6h inf vs control rep3, westar 6h control vs inf rep3 biological replicate: westar 12h inf vs control rep1, westar 12h inf vs control rep2, westar 12h inf vs control rep3 biological replicate: westar 12h control vs inf rep1, westar 12h control vs inf rep2, westar 12h control vs inf rep3 technical replicate - labeled-extract: westar 12h inf vs control rep1, westar 12h control vs inf rep1 technical replicate - labeled-extract: westar 12h inf vs control rep2, westar 12h control vs inf rep2 technical replicate - labeled-extract: westar 12h inf vs control rep3, westar 12h control vs inf rep3 biological replicate: westar 24h inf vs control rep1, westar 24h inf vs control rep2, westar 24h inf vs control rep3 biological replicate: westar 24h control vs inf rep1, westar 24h control vs inf rep2, westar 24h control vs inf rep3 technical replicate - labeled-extract: westar 24h inf vs control rep1, westar 24h control vs inf rep1 technical replicate - labeled-extract: westar 24h inf vs control rep2, westar 24h control vs inf rep2 technical replicate - labeled-extract: westar 24h inf vs control rep3, westar 24h control vs inf rep3 biological replicate: westar 48h inf vs control rep1, westar 48h inf vs control rep2, westar 48h inf vs control rep3 biological replicate: westar 48h control vs inf rep1, westar 48h control vs inf rep2, westar 48h control vs inf rep3 technical replicate - labeled-extract: westar 48h inf vs control rep1, westar 48h control vs inf rep1 technical replicate - labeled-extract: westar 48h inf vs control rep2, westar 48h control vs inf rep2 technical replicate - labeled-extract: westar 48h inf vs control rep3, westar 48h control vs inf rep3 biological replicate: westar 72h inf vs control rep1, westar 72h inf vs control rep2, westar 72h inf vs control rep3 biological replicate: westar 72h control vs inf rep1, westar 72h control vs inf rep2, westar 72h control vs inf rep3 technical replicate - labeled-extract: westar 72h inf vs control rep1, westar 72h control vs inf rep1 technical replicate - labeled-extract: westar 72h inf vs control rep2, westar 72h control vs inf rep2 technical replicate - labeled-extract: westar 72h inf vs control rep3, westar 72h control vs inf rep3
