Genes for wine quality

Researchers working within the CRC for Viticulture have identified two important wine quality genes in grapevine.

The team, led by Dr Simon Robinson in Adelaide, has been studying the synthesis of anthocyanins and tannins in grapes. These compounds are antioxidants beneficial to human health as well as important quality components, determining the colour and mouthfeel of red wine.

While the researchers had already characterised the anthocyanin pathway and identified the genes that control the process, the genes responsible for synthesising grape tannins were unknown.

Grape tannins are required to form stable red pigment complexes and provide mouthfeel in wine.

By looking at when and where in grapevine tannins were produced throughout berry development, and comparing similar genes in tobacco and the model plant Arabidopsis, the team was able to pinpoint two separate tannin production genes.

The researchers found that the genes are responsible for the production of chemically different types of condensed tannins, also known as proanthocyanidins (PAs).

The identification of two separate pathways to make different types of tannins in grapes holds promise for improving the mouthfeel of wine by improving grape tannin composition and could potentially allow vine breeders to control the levels of these important wine quality and human health compounds.

This project was carried out by CSIRO researchers within the CRC for Viticulture and was supported by an Australian Postgraduate Award and the Grape and Wine Research and Development Corporation.

Reference:
Proanthocyanidin Synthesis and Expression of Genes Encoding Leucoanthocyanidin Reductase and Anthocyanidin Reductase in Developing Grape Berries and Grapevine Leaves
Jochen Bogs, Mark O. Downey, John S. Harvey, Anthony R. Ashton, Gregory J. Tanner, and Simon P. Robinson Plant Physiology, October 2005, Vol. 139, pp. 652-663, www.plantphysiol.org

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