Voltage-dependent anion channel 2 (VDAC2) facilitates the accumulation of rice stripe virus in the vector Laodelphax striatellus

Rice stripe virus (RSV) causes enormous losses in rice production and is transmitted by the small brown planthopper, Laodelphax striatellus, in a persistent-propagative manner. RSV accumulation within the gut lumen of the vector is indispensable for the successful transmission to rice and insects. In this study, we obtained a 1464 bp full-length cDNA of a voltage-dependent anion channel 2 from L. striatellus (LsVDAC2), which encodes a 283 amino acid protein. RSV infection increased the expression of LsVDAC2 in the midguts and ovaries of L. striatellus by 260% and 228%, respectively. Silencing of LsVDAC2 resulted in a 88% reduction of RSV loads at 24 h after RNAi, indicating that LsVDAC2 facilitates RSV accumulation in the vector. Yeast two-hybrid and GST pulldown assays demonstrated that LsVDAC2 interacted with RSV RNA-dependent RNA polymerase, RdRp. Furthermore, experiments in vivo and in vitro showed that LsVDAC2 induced the apoptotic response in RSV-infected insects and tissues. Silencing of LsVDAC2 via RNAi significantly reduced the expression of genes for apoptosis-related caspases 1a and 1c by 62% and 78%, respectively, in RSV-infected vectors. Whether LsVDAC2-induced RSV accumulation is related to RSV RdRp and LsVDAC2-induced cell apoptosis deserves further investigation.