Abstract

RNA Silencing Based Approaches for Crop Improvement

Manchikatla Venkat Rajam, Professor & Head- Genetics, University of Delhi

RNA interference (RNAi) is a conserved sequence-specific gene silencing mechanism, which is triggered by the introduction of double-stranded RNA (dsRNA) leading to the cleavage of the target mRNA. RNAi has been applied successfully in different crop plants for the improvement of several desirable traits, including biotic stress tolerance. Since past two decades, my lab has been exploring RNAi technology for engineering crop plants for resistance against fungal infections and insect pests as well as other beneficial characters. RNAi strategy essentially involves the production of hairpin loop of dsRNA in transgenic plants targeting vital genes of pathogens and pests, which are absolutely essential for their growth and development. We examined the potential of RNAi for the control of Fusarium wilt in tomato (caused by Fusarium oxysporum f.sp lycopersici) by targeting a key polyamine biosynthesis gene, ornithine decarboxylase (ODC) of the pathogen. The target fungal ODC gene fragment was cloned in a hairpin RNA construct, which was used to generate several transgenic tomato plants. These transgenic lines expressed the intended siRNAs and exhibited moderate to high resistance against Fusarium wilt. We have also used RNAi-based approaches for developing tomato transgenic plants resistant to an important insect pest, Helicoverpa armigera, for enhanced shelf life of fruits and male sterility. The details of these results will be presented.