Tomato Solanum lycopersicum expressing the overlapping regions of three begomovirus genes exhibit resistance to Ageratum yellow vein Malaysia virus

Abstract

Abstract A post transcriptional gene silencing (PTGS) strategy to control virus replication through the expression of hairpin RNAi (hp-RNAi) could confer protection against geminiviruses and is a promising approach for developing virus-resistant tomato (Solanum lycopersicum) lines. We report the development of tomato lines showing resistance to Ageratum yellow vein Malaysia virus (AYVMV) a monopartite begomovirus and a causative agent for leaf curling, cupping, crinkling and stunting disease in the tomato cultivar MT1. The plants were transformed with a hp-RNAi construct “pHells-C1C2C3” consisting of overlapping regions of the C1, C2 and C3 genes of AYVMV. Progenies of two transgenic tomato lines (L132 and L18) exhibited resistance to AYVMV infection after inoculation with viruliferous whiteflies. The relative viral DNA accumulation levels at different times post inoculation were either not detectable or extremely low in these lines. There was also higher accumulation of siRNA in the asymptomatic transgenic lines, affirming the potential of this approach for developing begomovirus-resistant tomatoes. Our results also showed that siRNA corresponding to a short region overlapping the C1, C2 and C3 genes, induced resistance to AYVMV, indicating that it is not necessary to use the complete sequences of C1, C2 and C3 genes as targets for silencing. Furthermore, our transgenic tomato plants were found to be resistant to this virus which has a betasatellite. Therefore, targeting the begomovirus genome will be sufficient to achieve high levels of resistance even for AYVMV associated with betasatellite.