Assessment of Sesamia nonagrioides (Lepidoptera: Noctuidae) EcR and USP Genes as Targets for Exogenous Non-Persistent RNAi

Abstract

RNA interference (RNAi) is a transforming technology with high potential for practical applications in biology, including specific and safe insect pest control. For developing RNAi-based pest-control products no general recommendations exist and the best strategy needs to be determined for each insect pest separately on a case-by-case basis. In this research, the potential of silencing the genes encoding the subunits of the ecdysone receptor complex, EcR and Ultraspiracle (USP) by RNAi was evaluated in the corn borer, Sesamia nonagrioides, using different delivery approaches and targeting different developmental stages. In conjunction with our previous research it is demonstrated that prepupae are sensitive to RNAi triggered by dsRNA injection and that feeding of dsRNA-expressing bacteria throughout S. nonagrioides’ larval life can lead to limited developmental malformations with no potent insecticidal results. Our results, consistent with previous studies, indicated a great fluctuation of exogenous RNAi effectiveness in the Lepidopteran species, suggesting that further factors should be taken into consideration in order to expand this very promising field into the ‘’RNAi-resistant’’ insect species.

Host-induced silencing of the CpCHI gene resulted in developmental abnormalities and mortality in maize stem borer (Chilo partellus)

“…To evaluate the survival of 3 rd instar larvae, 200 μl of bacterially induced dsRNA as reported by [ 27 ] was compared with 15 μg of purified dsCHI. Previous studies have shown that lepidopterans are susceptible to high concentrations of dsRNA [ 28 ].…”