Functional Role of the PxGRHPR2 Gene in the Host Plant Adaptation of Diamondback Moth (Plutella xylostella)

The diamondback moth (Plutella xylostella), a major lepidopteran pest with a wide host range, presents persistent challenges to sustainable agriculture due to its high adaptability to cruciferous host plants. Although glyoxylate/hydroxypyruvate reductases (GRHPRs) have been well-characterized in plants and humans, their functional role in insects, particularly in host plant adaptation, remains largely unexplored. In this study, we characterized PxGRHPR2, a member of the GRHPR gene family, using a bioinformatics analysis, expression profiling, and CRISPR/Cas9-mediated gene knockout. RT-qPCR analysis showed that PxGRHPR2 was predominantly expressed in larval stage, with the highest transcript levels observed in the second instar and larval midgut tissues. Three homozygous PxGRHPR2 knockout strains were successfully generated using CRISPR/Cas9 system. Mutation of PxGRHPR2 led to significant reductions in larval weight, survival, and eclosion rates when larvae were fed on radish seedlings, whereas no such effects were observed under artificial diet conditions. These findings suggest that PxGRHPR2 plays a critical role in detoxification and metabolic regulation, thereby facilitating host plant adaptability in P. xylostella. Overall, this study provides new insights into insect-plant interactions and identifies PxGRHPR2 as a potential molecular target for developing sustainable pest management strategies.