CysL as a regulator of virulence in adaptation of the brown planthopper to resistant rice IR36

The brown planthopper ( Nilaparvata lugens , BPH) is one of the most destructive pests of rice. The prolonged cultivation of insect‐resistant rice varieties dominated by limited resistance genes has driven rapid BPH adaptation, while the underlying molecular mechanisms remain poorly understood. In this study, the resistant rice variety IR36 was used as the primary research material. Through trait segregation and transcriptome sequencing analysis of two contrasting BPH populations (susceptible P‐TN1 and virulent P‐IR36), 17 differentially expressed genes potentially associated with virulence variation were identified. Functional validation assays revealed that knockdown of cystathionine‐γ‐lyase ( CysL ) significantly reduced the virulence of BPH on IR36 rice, indicating that CysL markedly regulated BPH virulence against resistant rice carrying the brown planthopper resistance gene bph2 . These findings provide a novel genetic target for understanding and disrupting pest adaptation to resistant varieties.