Stemborer-induced rice plant volatiles boost direct and indirect resistance in neighboring plants (New Phytol)

Herbivore attack can trigger release of volatile organic compounds (VOCs) in numerous plant species. These airborne compounds from an infected plant act as messengers in plant-plant interactions causing adaptation to the stress in adjacent plants. Globally, rice is a staple food for millions of people, rendering pest infestation a large threat to rice growers. Yao et al. have shown that release of VOCs from rice plants infected with striped stem borer (SSB) caterpillars can induce both direct and indirect resistance to these pests in uninfected rice plants. Direct resistance was classified by increased jasmonic acid associated gene expression and increased defense priming in plants exposed to the SSB-induced VOCs and then to SSB caterpillars. While priming effects were observed for most genes by exposure to the caterpillar-induced VOCs, expression of defense related genes LOX8, DOX2 and CPI8 were upregulated before exposure to insects, suggesting defense induction prior to infection. Transmission of caterpillar induced VOCs including linalool, MeSA and DMNT increased attraction of parasitic wasps, a natural predator for SSB caterpillars, leading to indirect resistance. This research demonstrates the potential for exploiting airborne VOCs in priming natural defense responses in rice, a densely planted crop which therefore enhances possible plant-plant communication for this species. (Summary by Orla Sherwood, @orlasherwood) New Phytol. 10.1111/nph.18548