Silencing of Chitin Synthase A gene in Spodoptera litura (Fabricius) Using RNAi Approach

摘要

Tobacco cutworm, Spodoptera litura (Fabricius) is the major constraint for the production and productivity of several agricultural and horticultural crops. The most common and effective method for the management of S. litura is the use of insecticides. However, the extensive use of insecticides leads to environmental pollution, contamination of food materials and development of resistance in insect pests. Hence, there is an urgent need for the development of effective and alternative pest managementstrategy. Post-transcriptional gene silencing or RNA interference (RNAi) approach was found as an environmentally safe and effective method for the management of several lepidopteran and coleopteran insect pests. Thus, the present study was focused on the design of double-stranded RNA (dsRNA) mediated knockdown strategy for the management of S. litura targeting chitin synthase {SICHSA) gene. In this study, the SICHSA gene specific dsRNA was synthesized and assessed their effect on growth and developmentof S. litura under in vitro conditions. Comparatively lower larval body weight and moulting rate was observed on the larvae fed with dsSICHSA treated leaves than in untreated leaves. The moulting rate was recorded as 26.67 per cent where, the larvae fedwith dsSICHSA treated leaves during 4th moult. The result of the RT-qPCR analysis showed less expression level (6.25 fold) of SICHSA on larvae fed with dsSICHSA compared to control. The results suggested that SICHSA can be used as a good candidate genefor RNAi based insect pest control. The enhancement of expression level of dsSICHSA can be studied through plant mediated RNAi for developing an effective RNAi strategy against S. litura.