Plant Science

Fine-Tuning a Tart Grape

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Science  29 Mar 2013:
Vol. 339, Issue 6127, pp. 1499
DOI: 10.1126/science.339.6127.1499-b
CREDIT: © IRENE GRASSI

A good wine is a complex blend of flavors, at least some of which are based on the acidity of the wine, which is derived from the acidity of the grape. Grape berry acidity depends on potassium concentration, with high potassium content leading to less acidic fruit. As the grape berry ripens and sugars accumulate, potassium also accumulates. Potassium physiology in grape berries, however, is not well understood. Cuéllar et al. have now identified in grapevine (Vitis vinifera) a potassium channel, encoded by the gene VvK1.2, as well as kinase- and calcium-sensing partners that regulate the function of the channel. Accumulation of VvK1.2 transcripts, which are expressed in the berry flesh, accelerated with fruit ripening. Drought stress during the berry-ripening phase brought further increases in VvK1.2 transcript accumulation. Increased capacity for and regulation of potassium transport may be critical for successful ripening of the grape berry as it adjusts to fluctuating conditions that result from changes in internal vascular support and external drought conditions.

Plant J. 73, 1006 (2013).

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