The volatile indole primes rice defense against caterpillar attack (Plant Cell)

Herbivore-induced volatiles have been shown to prime plant defense response in multiple species. A new study by Ye et al. unveils some of the early signaling events in volatile-mediated defense priming in rice. The authors show that rice plants release increased amounts of the volatile indole when attacked by fall armyworm caterpillars. Indole pre-exposure induces expression and/or activity of several genes in early defense signaling pathways upon simulated herbivore attack. Among these, activation of a MAP kinase gene (OsMPK3) triggers increased jasmonate biosynthesis. Silencing of this gene reduces indole-primed herbivore resistance in rice plants. The authors conclude that rather than directly affecting caterpillar physiology, indole enhances rice resistance to caterpillar attack through priming of jasmonate-based defense signaling. (Summary by Saima Shahid) Plant Cell 10.1105/tpc.18.00569.