Jasmonic acid priming of potato uses hypersensitive response-dependent defense and delays necrotrophic phase change against Phytophthora infestans

Abstract

One of the most important diseases affecting potato is late blight, caused by the oomycete Phtytophthora infestans. The use of jasmonic acid has been reported to reduce the progression of the disease in potato, but the defense mechanisms involved in this response are unknown. In this study we described the effect of jasmonic acid as a priming agent over time in the defense response of potato against the invasion of P. infestans. We observed that the initial stimulus generated by the exogenous application of jasmonic acid had an effect on the stomatal conductance of the treated tissue and activated StMYC2 expression. Results reveal a priming effect in plants inoculated 11 days after treatment with jasmonic acid, evidenced by an increased transcriptional induction of defense-associated genes, decrease in the number of necrotic lesions and an evident reduction of lesion area (72.23%). Furthermore, in this study, we show that the tested concentration of jasmonic acid does not have an adverse effect at the physiological level in plants, since variation in stomatal conductance was transient, no change in chlorophyll a fluorescence and no early senescence in leaves was observed.