Dr. Xingyun Wang

Herbivory by one insect species can induce physiological changes in plants that enhance attraction and/or predation by other insect species. The striped stem borer (SSB), Chilo suppressalis (Walker), and the brown planthopper (BPH), Nilaparvata lugens (Stål), are pests of rice (Oryza sativa L.) that cause major losses in grain production. This study elucidates the molecular mechanism of SSB herbivory on subsequent feeding behaviors by BPH on rice. The planthopper-resistant rice variety ‘Mudgo’ was tested for BPH performance and behavior with or without SSB pre-feeding. BPH exhibited better growth and development and feeding behavior on SSB-damaged plants compared to healthy plants. Gene expression and phytohormone level analysis revealed modifications in the jasmonic acid (JA) biosynthesis in response to SSB feeding. The analysis of central metabolites and volatiles showed that SSB-damaged stems induced volatile emissions, which benefits planthopper development or attracts BPH. In summary, we found that the JA biosynthesis was triggered by SSB and played a vital role in rice defense against BPH, which provides insight into the molecular and biochemical mechanisms of preference of BPH for SSB-damaged rice plants. Our results expose the importance of inter-species interactions in host plant resistance to insect pests, and might provide the foundation for the control of BPH and evaluation of their resistance in rice germplasm.