Reddy K R K, Rajam M V
Department of Genetics, University of Delhi South Campus, Benito Juarez Marg, New Delhi, 110021, India.
Sri Biotech Laboratory India Ltd., Street No. 2, Sagar Society, Road No. 2, Banjara Hills, Hyderabad, 500034, India.
Plant Mol Biol. 2016 Feb;90(3):281-92. doi: 10.1007/s11103-015-0414-y. Epub 2015 Dec 10.
Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a devastating agricultural insect pest with broad spectrum of host range, causing million dollars crop loss annually. Limitations in the present conventional and transgenic approaches have made it crucial to develop sustainable and environmental friendly methods for crop improvement. In the present study, host-induced RNA interference (HI-RNAi) approach was used to develop H. armigera resistant tobacco and tomato plants. Chitinase (HaCHI) gene, critically required for insect molting and metamorphosis was selected as a potential target. Hair-pin RNAi construct was prepared from the conserved off-target free partial HaCHI gene sequence and was used to generate several HaCHI-RNAi tobacco and tomato plants. Northern hybridization confirmed the production of HaCHI gene-specific siRNAs in HaCHI-RNAi tobacco and tomato lines. Continuous feeding on leaves of RNAi lines drastically reduced the target gene transcripts and consequently, affected the overall growth and survival of H. armigera. Various developmental deformities were also manifested in H. armigera larvae after feeding on the leaves of RNAi lines. These results demonstrated the role of chitinase in insect development and potential of HI-RNAi for effective management of H. armigera.
棉铃虫（Helicoverpa armigera Hübner，鳞翅目：夜蛾科）是一种具有广泛寄主范围的毁灭性农业害虫，每年造成数百万美元的作物损失。目前传统方法和转基因方法的局限性使得开发可持续且环境友好的作物改良方法变得至关重要。在本研究中，采用寄主诱导的RNA干扰（HI-RNAi）方法培育抗棉铃虫的烟草和番茄植株。选择对昆虫蜕皮和变态至关重要的几丁质酶（HaCHI）基因作为潜在靶标。从保守的无脱靶部分HaCHI基因序列制备发夹RNAi构建体，并用于培育多个HaCHI-RNAi烟草和番茄植株。Northern杂交证实了HaCHI-RNAi烟草和番茄株系中产生了HaCHI基因特异性的小干扰RNA。持续取食RNAi株系的叶片会大幅降低靶基因转录本，从而影响棉铃虫的整体生长和存活。取食RNAi株系叶片后，棉铃虫幼虫还出现了各种发育畸形。这些结果证明了几丁质酶在昆虫发育中的作用以及HI-RNAi对有效防治棉铃虫的潜力。
