Plant‐mediated gene silencing of an essential olfactory‐related Gqα gene enhances resistance to grain aphid in common wheat in greenhouse and field

BACKGROUND Grain aphid (Sitobion avenae F.) is a dominant pest that limits cereal crop production around the globe. Gq proteins have important roles in signal transduction in insect olfaction. Plant‐mediated RNA interference (RNAi) has been widely studied in insect control, but its application for the control wheat aphid in the field requires further study. Here, we used double‐stranded (ds)RNA feeding to verify the potential of selected Gqα fragments for host‐mediated RNAi, and then evaluated the effect of RNAi on aphid olfaction in transgenic wheat in the greenhouse and field. RESULTS Gqα gene was expressed in the aphid life cycle, and a 540 bp fragment shared 98.1% similarity with the reported sequence. dsGqα feeding reduced the expression of Gqα, and both reproduction and molting in the grain aphid. Feeding transgenic lines in the greenhouse downregulated expression of aphid Gqα, and significantly reduced reproduction and molting numbers. Furthermore, our field results indicate that transgenic lines have lower aphid numbers and higher 1000‐grain weight than an unsprayed wild‐type control. CONCLUSION Plant‐mediated silencing of an essential olfactory‐related Gqα gene could enhance resistance to grain aphid in common wheat in both the greenhouse and the field. © 2018 Society of Chemical Industry A 540 bp fragment of grain aphid Gqα gene was cloned, and its corresponding dsGqα feeding significantly reduced the expression level of Gqα and reproduction and molting of grain aphid. Therefore this DNA fragment was used to construct the RNAi vector for plant mediated RNAi. The transgenic lines not only significantly reduced the reproduction and molting numbers in greenhouse, but also showed less aphid number and higher 1,000‐grain weight than the wildtype in field.