RNA interference-mediated resistance to Tobacco streak virus in transgenic peanut

Peanut stem necrosis disease (PSND) caused by Tobacco streak virus (TSV) is one of the important diseases of peanut (Arachis hypogaea L.) worldwide. In this study, we investigated the possibility of developing PSND- resistant transgenic peanut plants using RNAi technique. Peanut cultivar TMV-7 was transformed with a hairpin RNA (hpRNA) vector, pART27-TSV-IR-CP, containing inverted repeats of TSV-coat protein (CP) gene sequence flanking a spacer sequence (Pdk Intron) under the control of the CaMV 35S promoter using Agrobacterium tumefaciens -mediated transformation method. The presence of the TSV CP gene sequence in T₀, T₁ and T₂ transgenic plants was confirmed by PCR analysis using CP gene specific primers. Evaluation of the transgenic plants (T₂ generation) for resistance to TSV by using sap inoculation method revealed that none of the inoculated transgenic plants showed symptoms of infection, whereas non-transgenic control plants showed necrosis of leaves 7–9 days after inoculation and stem necrosis 16–19 days after inoculation. This study suggests that resistance against TSV can be induced in peanut plants through genetic engineering by expressing dsRNA of coat protein gene of TSV as target for RNAi.