Functional dissection of conserved RNAi pathways reveals Dicer2-independent antiviral defense against RNA viruses in hemipteran insects

The functional divergence of RNAi pathways in non-model insects remains poorly understood. Using the hemipteran Laodelphax striatellus, we demonstrated that miRNA and piRNA pathways are essential for development but not antiviral defense. Surprisingly, the canonical siRNA gene DCLDCR2 was also dispensable for controlling diverse RNA viruses, a trait conserved across Hemiptera (S. furcifera, N. lugens, B. tabaci). Instead, CRISPR/Cas9 knockout revealed that DCLDCR2 is critical for embryogenesis. Our study challenges the canonical view of siRNA immunity, suggesting that in hemipteran insects, DCLDCR2 functions primarily in development rather than antiviral immunity.