Transcriptome profiling of the defense response following elicitation by a bacterial pathogen or flg22

Phytoalexins are abundant in edible crucifers and have important biological activities, yet no dedicated gene for their biosynthesis is known. Here, we report two new cytochromes P450 from the non-model plant Brassica rapa (Chinese cabbage) that catalyze unprecedented S-heterocyclizations in cyclobrassinin and spirobrassinin biosynthesis. Our results reveal the first genetic and biochemical insights into the biosynthesis of a prominent pair of dietary metabolites, and have important implications for pathway discovery across >20 recently sequenced non-model crucifers. Overall design: Leaf mRNA profiles of four conditions (Pseudomonas syringae pv. maculicola, flg22, and their respective mock treatments) were tested in triplicate.