Plant-mediated RNAi of grain aphid CHS1 gene confers common wheat resistance against aphids

Chitin is an important component of the insect exoskeleton and peritrophic membrane. Chitin synthase 1 (CHS1) is a key enzyme in the chitin synthesis pathway, and has a role in insect molting and growth. Plant-mediated RNA interference (RNAi) has been used as a more target-specific and environmentally safe approach to prevent and control agricultural insects. The aims of this study were to use grain aphid (Sitobion avanae) CHS1 as the target gene and to produce transgenic wheat lines for aphid control via plant-mediated RNAi.

Expression levels of CHS1 changed at different developmental stages. After feeding on the representative T₃ transgenic lines Tb5-2 and Tb10-3, CHS1 expression levels in grain aphid decreased by 50.29% and 45.32%, respectively; and total and molting aphid numbers reduced significantly, compared with controls. Consistent with this, aphid numbers in mixed natural populations reduced significantly in the respective T₄ and T₅ transgenic lines under field conditions, and T5 transgenic lines had higher grain weight compared with the unsprayed insecticide wild-type and insecticide-sprayed wild-type.

These results indicate that plant-mediated RNAi of the grain aphid CHS1 gene confers common wheat resistance against aphids. © 2018 Society of Chemical Industry.