RNAi-mediated held-out wing (HOW) gene knockdown inhibits wing expansion of white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae)

The white-backed planthopper (Sogatella furcifera), a major migratory pest of rice, has resistance to various chemical treatments. The developmental regulation gene "held-out wing (HOW)" gene can serve as a potential target for RNA interference (RNAi) pesticides. Here, we analyzed spatiotemporal expression pattern and biological function of SfHOW by RNAi-mediated gene silencing. The SfHOW gene contains 628 bp and encodes 196 amino acids. SfHOW was highly expressed in 3rd instar nymphs, followed by 5th instar nymphs. In different tissues, SfHOW is most abundantly expressed in epidermis, with lower levels in wings and legs, and the least expression observed in fat body and gut. RNAi-mediated silencing of SfHOW resulted in a marked decrease in its transcription levels, leading to mortality of 66.8 %. Additionally, 62.0 % emerged adults exhibited folded and curled wings, indicating that SfHOW is crucial for wing expansion of S. furcifera. Following SfHOW silencing, significant reductions in the expression of S. furcifera Apterous (SfAp), suggesting that SfHOW may regulate wing expansion by modulating SfAp, so as to regulate the expression of Dpp gene to participate in the regulation of expansion. This study identified a new target for the development of RNAi-based pesticides for rice pest control and enhances molecular understanding of wing development in Hemipteran insects.