Cytochrome P450 Monooxygenases and Regulate Rice Black-Streaked Dwarf Virus Replication in (Fallén).

The small brown planthopper, (Fallén), is an important agricultural pest that causes significant losses by sucking and transmitting multiple plant viruses, such as rice black-streaked dwarf virus (RBSDV). Insecticides are commonly used to control planthoppers and cause the induction or overexpression of cytochrome P450 monooxygenases (P450s) from the CYP3 and CYP4 clades after insecticide application. However, little is known about the roles of insecticides and P450s in the regulation of viral replication in insects. In this study, RBSDV-infected were injected with imidacloprid, deltamethrin, pymetrozine, and buprofezin, respectively. The insecticide treatments caused a significant decrease in RBSDV abundance in . Treatment of piperonyl butoxide (PBO), an effective inhibitor of P450s, significantly increased the RBSDV abundance in . Fourteen P450 candidate genes in the CYP3 clade and 21 in the CYP4 clade were systematically identified in , and their expression patterns were analyzed under RBSDV infection, in different tissues, and at different developmental stages. Among the thirty-five P450 genes, the expression level of was the highest, while was the lowest after RBSDV infection. Knockdown of and significantly increased the virus abundance and promoted virus replication in . Overall, our data reveal that and play a critical role in the regulation of virus replication in .