Host-delivered RNA interference in tomato for mediating resistance against Meloidogyne incognita and Tomato leaf curl virus

Tomato is a key vegetable crop cultivated in nearly all agricultural regions of the world. It is a protective food very rich in vitamin A and C. Worldwide two major biotic stresses namely root-knot nematode (Meloidogyne incognita) and tomato leaf curl virus (ToLCV) pose a serious threat to its production. Serious environmental concerns associated with the chemical pesticides used for management of these pests compel researchers to look for alternate management strategies. Many recent publications indicate engineering resistance through host delivered RNAi to be an important, sustainable and efficient tool for nematode and virus management. In this study, we have attempted to engineer resistance against M. incognita and ToLCV by stacking dsRNA constructs of the Integrase gene of M. incognita and AC4 genes of ToLCV, using co-transformation protocol in tomato. Transgenic events, so produced, were confirmed at the molecular level by PCR and southern blot. Such T2 events showed absolute absence of leaf curl virus disease symptoms and 62–63% reduction in the number of galls, 51–70% reduction in the number of eggs, 31–38% reduction in number of eggs per egg mass and 66–81% reduction in nematode multiplication factor when compared to the untransformed control plants.The study provides an evidence for generating resistance through RNAi against multiple biotic stresses.