Overexpression of potato transcription factor (StWRKY1) conferred resistance to Phytophthora infestans and improved tolerance to water stress

Potato (Solanum tuberosum) late blight caused by oomycete Phytophthora infestans (Pi) is highly destructive to potato yield and cost huge losses each year. Regulation of a network of transcription machinery, controlled by transcription factors (TF’s), is required to overcome the susceptibility. WRKY TF’s are known to regulate transcription machinery upon biotic and abiotic stresses in different crop plants. We cloned and characterized a WRKY gene, StWRKY1, from potato cDNA synthesized from Pi infested leaves. StWRKY1 protein localized typically in the nucleus. Overexpression (OE) of StWRKY1 positively regulates Pi resistance as well as drought tolerance in transgenic potato. The elevated resistance in OE lines was co-related with higher accumulation of pathogenesis-related (PR) genes as compared to untransformed control plants. Interestingly, increased susceptibility of co-suppression (CSP) plants was associated with down regulation of PR genes expression. Moreover, transgenic lines overexpressing StWRKY1 showed tolerance in terms of less rate of water loss, during dehydration assay. Importantly, expression of StWRKY1 was upregulated upon treatment with plant hormones, suggesting its involvement in basal signal transduction pathway. Overall, our findings provided evidence that StWRKY1 positively regulate biotic and abiotic stress resistance thereby modulating plant basal defense networks, thus play a significant role for crop improvement.