Identification and functional expression in yeast of a grape berry sucrose carrier

A large increase in hexose accumulation is typical of grape berry ripening. To analyse sugar transport processes during grape berry (Vitis vinifera L. cv Ugni Blanc) development, a cDNA encoding for a sucrose transporter, designated VvSUT1 was cloned. Sucrose transport activity of the VvSUT1 protein was demonstrated by heterologous expression in yeast. A study of gene expression along berry development showed that VvSUT1 transcripts are present at all stages but accumulate with the onset of ripening. This work shows that sucrose transport at the plasma membrane of grape berry cells may play a role in the accumulation of sugars during maturation.