Involvement of jasmonic acid (JA) in phytoalexin production in rice

Abstract

In this study, we investigated the role of JA in phytoalexin production in rice using the JA-deficient cpm2 mutant. Firstly, it was confirmed that wound-induced production of JA was severely suppressed in cpm2 plants. Then we performed quantification of phytoalexins in CuCl2-treated rice leaves. The mutant leaves showed no significant difference from wild-type leaves in CuCl2-induced production of diterpenoid phytoalexins such as momilactones and phytocassanes. On the other hand, CuCl2-induced production of the flavonoid phytoalexin sakuranetin was severely suppressed in cpm2 leaves. This suppression was cancelled by the addition of JA. These data suggest that JA or metabolically related compounds are essential for the production of sakuranetin, but not for the production of diterpenoid phytoalexins.