Metabolism of terpenes in the response of grape (Vitis vinifera L.) leaf tissues to UV-B radiation

GIL M, PONTIN M, BERLI F, BOTTINI R, PICCOLI P

PHYTOCHEMISTRY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2011

0031-9422

This study investigated the terpene profile analyzed by GC-EIMS of in vitro cultured plants of Vitis vinifera exposed to a “field-like” dose of UV-B (4.75 kJ m-2 d-1) administered at two different fluence rates (low, 16 h at 8.25 ìW cm-2, and high 4 h at 33 ìW cm-2). Low UV-B incremented the membrane-related triterpenes sitosterol, stigmasterol and lupeol, more noticeable in young leaves, suggesting elicitation of a mechanism for grapevine acclimation. In contrast, accumulation of compounds with antioxidant properties, the diterpenes á and ã tocopherol and phytol, the sesquiterpene E-nerolidol and the monoterpenes carene, á-pinene and terpinolene revealed maximum accumulation under high UV-B, which was accentuated in mature leaves. Also the levels of the sesquiterpenic stress-related hormone abscisic acid (ABA) increased under high UV-B, although 24 h post irradiation ABA concentrations decreased. Such increments of antioxidant terpenes along with ABA suggest elicitation of mechanisms of defense. The adaptative responses induced by relatively low UV-B irradiation as suggested by synthesis of terpenes related with membrane stability correlated with augments in terpene synthase activity.