Differential Performance of Vector and Non-Vector Planthoppers on Virus-Infected vs. Mock-Infected Plants

The southern rice black-streaked dwarf virus (SRBSDV) is transmitted by the white-backed planthopper (WBPH), Sogatella furcifera, but not by the co-occurring brown planthopper (BPH), Nilaparvata lugens. Understanding the influence of virus infection of host plants on the performance of close-related vector and non-vector species is an interesting topic for exploring virus–plant–herbivore interactions. This study investigates how SRBSDV infection of rice plants affects the performance of WBPH and BPH and the plant defense responses. Differential performance of the two planthopper species was observed. On infected plants, WBPH displayed prolonged male nymphal development, increased adult longevity, enhanced feeding, and reduced fecundity, which contrasts the reduced nymph survival and fecundity in BPH. SRBSDV infection triggered an increase in salicylic acid (SA) levels and upregulated the expression of SA-related genes (ICS1 and NPR1) in response to WBPH feeding, but not to BPH feeding. These results show that SRBSDV reshapes the host plant defense in a manner that alters key vector traits favoring virus transmission while impairing the fitness of a competing non-vector, which advances current understanding of virus–plant–herbivore interaction.