Effect of Exogenous NaCl On Anthocyanin Accumulation and Biosynthesis of Cabernet Sauvignon Grape Berries

Abstract Backgroud: The coloring mechanism of grape (Vitis vinifera L.) berry in response to salinity during maturation is poorly understood. To determine the effect of salinity on fruit quality, especially anthocyanin accumulation, the grapevine cultivar Cabernet Sauvignon were sprayed with different concentrations of sodium chloride. Dynamic changes in anthocyanin accumulation and eight biosynthetic enzyme activities during maturation were also investigated to clarify the anthocyanin biosynthesis regulation. Results The analysis showed that the fruit’s fresh weight was decreased by NaCl spray. But the grape quality including reducing sugar, soluble sugars, total phenols and tannins increased significantly on harvest time. Ten individual anthocyanins were detected from the skin of Cabernet Sauvignon by ultra performance liquid chromatography (UPLC). And there was a significantly greater accumulation of total anthocyanin contents under salt treatment. The NaCl spray provoked metabolic responses in grapes and enhanced biosynthetic enzyme activities during riping. Correlation analysis showed that anthocyanin accumulation was closely related to the key enzyme LDOX both in the control and 100 mM NaCl treatment berries. Conclusion The application of NaCl to grape foliage effectively increase the quality of the Cabernet Sauvignon grape, improving soluble sugar, organic acid, phenolics and tannin contents, and the total anthocyanin contents in grape skins after varasion. These findings provide novel insight into the crucial factors that directly modulate anthocyanin biosynthesis and consequently control grape coloration.