Distribution of resveratrol and stilbene synthase in young grape plants (Vitis vinifera L. cv. Cabernet Sauvignon) and the effect of UV-C on its accumulation

Current research indicated that the resveratrol was mainly accumulated in the skin of grape berry, however, little is yet known about the distribution of resveratrol, as well as the regulation mechanism at protein level and the localization of stilbene synthase (malonyl-CoA:4-coumaroyl-CoA malonyltransferase; EC 2.3.1.95; STS), a key enzyme of resveratrol biosynthesis, in young grape plants (Vitis vinifera L. cv. Cabernet Sauvignon). Resveratrol, whose constitutive level ranged from 0.2 mg kg−1 FW to 16.5 mg kg−1 FW, could be detected in stem, axillary bud, shoot tip, petiole, root and leaf of grape plants. Among them, stem phloems presented the most abundant of resveratrol, and the leaves presented the lowest. Interestingly, the level of STS mRNA and protein were highest in grape leaves. And the analysis of immunohistochemical showed the tissue-specific distribution of STS in different organs, presenting the similar results compared with the amount of protein. And the subcellular localization revealed that the cell wall in different tissues processed the most golden particles representing STS. Subjecting to UV-C irradiation, resveratrol and STS were both intensely stimulated in grape leaves, with the similar response pattern. Results above indicated that distribution of resveratrol and STS in grape was organ-specific and tissue-specific. And the accumulation of resveratrol induced by UV-C was regulated by transcriptional and translational level of STS.