RESUMO
Helicoverpa armigera causes huge crop losses due to its polyphagous nature. The present study demonstrates the use of artificial microRNA (amiRNA) mediated gene silencing approach to generate insect resistant tomato plants. Ecdysone receptor (HaEcR) gene of the target pest, H. armigera, which is involved in the regulation of all developmental stages of the insect life cycle, was silenced by sequence-specific amiRNA (amiRNA-HaEcR). Continuous feeding on detached tomato leaves expressing the amiRNA-319a-HaEcR resulted in reduced target gene transcripts and affected the overall growth and survival of H. armigera. Not only the target gene was down-regulated but, the feeding also affected the expression of down-stream genes involved in the ecdysone signaling pathway. The resistant trait was also observed in T1 generation of tomato transgenic lines. These results further established the role of EcR as a master regulator in insect development and effectiveness of amiRNA technology for efficient control of H. armigera.