Abstract
Antimicrobial diterpenoid compounds such as momilactones and phytocassanes are major phytoalexins produced in rice upon pathogen attack. We previously reported that six cytochrome P450 monooxigenase (P450) genes compose a gene cluster with the diperpene cyclase genes for phytocassanes biosynthesis on chromosome 2, and confirmed that CYP71Z7 is involved in the biosyntheses of phytocassanes A, B and D.
Here, we investigated the functions of other P450s, CYP76M5 to CYP76M8, which are located on the phytocassanes biosynthetic gene cluster, by generating their RNAi lines. One of the RNAi lines did not show any production of phytocassanes after elicitor treatment, whereas another line exhibited an ability to produce only phytocassane A, suggesting that these RNAi lines seem to have differential effects on the expression of target P450 genes in the cluster. Expression profiling of these P450 genes in the RNAi lines will help us to know steps catalyzed by these P450s in the biosynthetic pathway for phytocassanes.
