title: Metabolism of terpenes in the response of grape (Vitis vinifera L.) leaf tissues to UV-B radiation.
abstract: This study investigated the terpene profiles as determined by GC-EIMS analysis 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 μW cm(-2), and high 4 h at 33 μW cm(-2)). Low UV-B treatment increased levels of the membrane-related triterpenes sitosterol, stigmasterol and lupeol, more notable in young leaves, suggesting elicitation of a mechanism for grapevine acclimation. By contrast, accumulation of compounds with antioxidant properties, diterpenes α and γ tocopherol and phytol, the sesquiterpene E-nerolidol and the monoterpenes carene, α-pinene and terpinolene had 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 mechanism of defense. The adaptative responses induced by relatively low UV-B irradiations as suggested by synthesis of terpenes related with membrane stability correlated with augments in terpene synthase activity.
authors.affiliation: Laboratorio de Bioquímica Vegetal, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Tecnológicas-Universidad Nacional de Cuyo, Almirante Brown 500, M5528AHB Chacras de Coria, Argentina.
authors.forename: Mariana
authors.initials: M
authors.lastname: Gil
authors.forename: Mariela
authors.initials: M
authors.lastname: Pontin
authors.forename: Federico
authors.initials: F
authors.lastname: Berli
authors.forename: Rubén
authors.initials: R
authors.lastname: Bottini
authors.forename: Patricia
authors.initials: P
authors.lastname: Piccoli
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000222:Adaptation, Physiological; D008401:Gas Chromatography-Mass Spectrometry; D010840:Phytosterols / Q000096:biosynthesis; D018515:Plant Leaves / Q000378:metabolism / Q000528:radiation effects; D025341:Principal Component Analysis; D013312:Stress, Physiological; D013729:Terpenes / Q000737:chemistry / Q000378:metabolism*; D014466:Ultraviolet Rays; D027843:Vitis / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D010840:Phytosterols; D013729:Terpenes; D000040:Abscisic Acid