SRBSDV-derived small interfering RNAs modulate insect vector reproduction and viral replication in Sogatella furcifera

Transmitted through insect vectors, plant viruses directly affect vector behavior and phenotype post-infection and subsequently trigger the insect innate immune pathways. However, the underlying molecular mechanisms remain elusive. Here, we demonstrate that Southern rice black-streaked dwarf virus (SRBSDV) infection in the white-backed planthopper (WBPH) downregulates Tre1 expression through virus-derived small interfering RNAs (vsiRNA, vsiR-t00210173 and vsiR-t00736550), thereby mediating the trehalose metabolic pathway in WBPH. Consequently, this leads to dysregulation of trehalose levels, resulting in suppressed ovarian development. Further investigation reveals that vsiR-t00736550 targets the immune gene Toll8 in the WBPH, suppresses its expression, and ensures normal viral replication. These results suggest that plant arboviruses can modulate their insect vectors by targeting vector genes through derived vsiRNAs. This finding contributes to a better understanding of vector-virus interactions and informs strategies for controlling both WBPH and SRBSDV.