Transgenic plants expressing immunosuppressive dsRNA improve entomopathogen efficacy against Spodoptera littoralis larvae

Transgenic plants that express double-stranded RNA (dsRNA) targeting vital insect genes have recently emerged as a valuable new tool for pest control. In this study, tobacco plants were transformed to produce dsRNA targeting Sl 102 gene that is involved in the immune response of Spodoptera littoralis larvae, a serious lepidopteran pest of several crops. Experimental larvae reared on transgenic tobacco lines showed (1) a strongly reduced level of Sl 102 transcripts, which was positively associated with food consumption; (2) a substantial impairment of the encapsulation response mediated by hemocytes; and (3) a marked increase in the susceptibility to Xentari (TM), a Bacillus thuringiensis-based insecticide. Importantly, this approach may allow a reduction in the doses of B. thuringiensis used for field applications and enhance its killing activity on mature larvae. The results obtained thus support the use of immunosuppressive RNAi plants to enhance the performance of microbial insecticides on lepidopteran larvae.

Automated summary

Transgenic plants expressing dsRNA targeting essential insect genes have shown to be effective in controlling pests. In this study, tobacco plants were transformed to produce dsRNA targeting Sl 102 gene involved in the immune response of Spodoptera littoralis larvae. Experimental results demonstrated that larvae reared on these transgenic tobacco lines exhibited decreased gene expression, impaired encapsulation response, and increased susceptibility to insecticide. This approach could potentially reduce the use of insecticides and enhance their efficacy against mature larvae.