Resveratrol accumulation and resveratrol synthase gene expression in response to abiotic stresses and hormones in peanut plants

The peanut is one of the limited number of plant species that synthesize resveratrol, which is both a phytoalexin with antifungal activity and a phytochemical associated with reduced cancer risk and reduced cardiovascular disease. We investigated resveratrol content and resveratrol synthase gene expression in response to various stresses and hormones in order to understand the mode of resveratrol synthesis in peanut plants. Resveratrol was present in substantial amounts (1.2–2.6 μg/g FW) in leaves, roots and shells, but very little (0.05–0.06 μg/g FW) was found in developing seeds and seed coats of field-grown peanuts. Accumulation of resveratrol in leaves increased over 200-fold in response to UV light, over 20-fold in response to paraquat, and between two- and ninefold in response to wounding, H2O2, salicylic acid (SA), jasmonic acid and ethephon, 24 h after treatment. No accumulation of resveratrol was induced by abscisic acid. Changes in resveratrol content were correlated with levels of RS mRNA, indicating a transcriptional control of resveratrol synthase activity. The results suggest that resveratrol synthesis is induced by biotic and abiotic factors through the regulation of RS transcription, and that stress hormones such as SA and ethylene are involved in the RS gene expression in peanut.