Project description:Gene expression changes during the initial stages of black spot disease caused by Alternaria brassicicola on Brassica oleracea (Brassica oleracea var. capitata f. alba, white cabbage) leaves were investigated with Arabidopsis thaliana oligonucleotide microarrays. Transcriptional profiling of infected B. oleracea leaves revealed that photosynthesis was the most negatively regulated biological process. The negative regulation of 6 photosynthesis-related genes, mainly the genes involved in the photosynthesis light reaction and Calvin cycle, was observed as early as 12 hours post infection (hpi). It progressed through 48-hpi stage, when 44 down-regulated photosynthesis-related genes were detected. The analyses of infected leaves at microscopic, ultrastructural and physiological levels supported the microarray-based observations and indicated that the photosynthetic processes are suppressed in B. oleracea as a result of the fungal infection.