Isolation of jasmonate-induced sesquiterpene synthase of rice: product of which has an antifungal activity against Magnaporthe oryzae

Abstract

Rice is one of the most important crops worldwide, and it is a model for molecular studies of monocotyledonous species, particularly for understanding the molecular mechanisms of plant disease resistance. Jasmonic acid (JA) is an important plant hormone involved in rice-pathogen interactions. In addition, JA-induced volatiles are known to be involved in the rice defense system regulated by JA signaling. In this study, we isolated a JA-induced terpene synthase from rice, and found that it produces two sesquiterpenes; β-elemene and β-bisabolene. Furthermore, β-elemene exhibited significant antifungal activity against Magnaporthe oryzae; however it did not exhibited any antibacterial activity against Xanthomonas oryzae pv. oryzae. JA-induced accumulation of β-elemene was regulated by OsJAZ8, a rice jasmonate ZIM-domain (JAZ) protein that is involved in the JA signaling pathway, suggesting that β-elemene plays an important role in JA-induced resistance, and that it functions as an antifungal compound in rice.

Keywords: Jasmonic acid; Magnaporthe oryzae; Plant volatile; Terpene synthase; β-Elemene.