The HcUGT40R20 mediates the host plant adaptation of Hyphantria cunea: Providing a potential target for RNAi-based formulation control strategies

The remarkable host adaptability of Hyphantria cunea contributes to its invasiveness and destructive impact. This study investigates the molecular mechanisms underlying the multi-host adaptability in H. cunea larvae, focusing on UDP-glucuronosyltransferases (UGT). The results revealed a significant increase in UGT enzyme content in H. cunea larvae feeding on low-preference host plants compared to those on high-preference hosts. UGT inhibitor treatment markedly reduced larval body weight and food intake across all host plant groups. Additionally, qPCR analysis indicated distinct expression patterns of UGT family genes in larvae feeding on different host plants. Notably, HcUGT40R20 was highly expressed specifically in larvae consuming intermediate- and low-preference hosts. Functional analysis showed that silencing HcUGT40R20 led to a significant decrease in larval body weight and disrupted the expression of genes involved in energy metabolism and growth regulation across all host plant groups, along with a marked increase in larval mortality in intermediate- and low-preference hosts. Moreover, the bio-toxicity of the host plant defensive compounds, cytisine and coumarin, was significantly reduced in transgenic Drosophila and Sf9 cells overexpressing HcUGT40R20 . Furthermore, an RNAi-based formulation, CS-ds HcUGT40R20 , was successfully developed using chitosan (CS) nanomaterials and dsRNA, demonstrating stability in the gut fluid of H. cunea . CS-ds HcUGT40R20 treatment significantly reduced the body weight of larvae fed on different host plants and markedly increased the mortality rate of larvae under coumarin stress. In conclusion, HcUGT40R20 plays a critical role in the multi-host adaptability of H. cunea , and RNAi-based formulation targeting HcUGT40R20 provide an effective strategy for controlling H. cunea .