Suppression of a leucine-rich repeat receptor-like kinase enhances host plant resistance to a specialist herbivore

The mechanisms by which herbivores induce plant defenses are well studied. However, how specialized herbivores suppress plant resistance is still poorly understood. Here, we discovered a rice (Oryza sativa) leucine-rich repeat receptor-like kinase,OsLRR-RLK2, which is induced upon attack by gravid females of a specialist piercing-sucking herbivore, the brown planthopper (BPH,Nilaparvata lugens). SilencingOsLRR-RLK2decreases the constitutive activity of mitogen-activated protein kinase (OsMPK6) and alters BPH-induced transcript levels of several defense-related WRKY transcription factors. Moreover, silencingOsLRR-RLK2reduces BPH-induction of jasmonic acid and ethylene but promotes the biosynthesis of both elicited salicylic acid and H2O2; silencing also enhances the production of volatiles emitted from rice plants infested with gravid BPH females. These changes decrease BPH preference and performance in the glasshouse and the field. These findings suggest that OsLRR-RLK2, by regulating the plant's defense-related signaling profile, increases the susceptibility of rice to BPH, and that BPH infestation influences the expression of OsLRR-RLK2, suppressing the resistance of rice to BPH.