PROTEOMIC MODULATION OF VITIS VINIFERA CV. MALBEC IN RESPONSE TO SOLAR UV-B IN A HIGH-ALTITUDE VINEYARD OF MENDOZA – ARGENTINA

LEONARDO ARIAS; GERMÁN MURCIA; FLAVIO MUÑOZ; FEDERICO BERLI; ARIEL FONTANA; PATRICIA PICCOLI

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

Grapevine cultivation at high altitudes offers cooler, more suitable environmental conditions for premium quality winemaking in the context of climate change. Apart from lower mean temperatures and higher thermal amplitudes, grapes experience a significantly larger intensity of UV-B radiation due to lower air turbidity. UV-B serves both as a developmental signal and an oxidative-stress-inducing element depending on its intensity and the cultivar’s ability to cope with it. Grapes usually respond to high UV-B by generating UV blocking anthocyanins and a myriad of antioxidant compounds and enzymes to prevent damage. This is often desirable for wine production, as it enhances organoleptic properties and aging capacity. In this work we show how Malbec grapes modulate their proteome and secondary metabolism in response to the solar UV-B found at a high-altitude vineyard (1350 m a.s.l.) in Mendoza, Argentina. Functional categories and STRING clusters constructed with differentially expressed proteins display a strong regulation of primary and secondary metabolism, redox balance and antioxidant system. Additionally, proteinsrelated to ABA biosynthesis and defense response were upregulated by UV-B, suggesting an enhanced capacity to deal with general stress. In accordance, low molecular weight polyphenols with antioxidant and phytoalexin properties, such as procyanidins, flavonols and stilbenes were found in much higher concentrations with high UV-B in pre-veraison. While total and di-hydroxylated anthocyanins were more abundant with higher UV-B at harvest. This is the first report of grape proteomic modulation in response to solar UV-B, and it bears special importance for grape cultivation for high-quality winemaking in present and future climate scenarios.