While low levels of salt in grapes can improve the flavor of wine, too much leads to unpalatable tastes, a reduction in fruit yield and damage to grapevines.
Excess salt is a problem experienced by wine regions worldwide: in Australia, issues caused by salinity across food and wine agriculture have been estimated to cost more than A$1bn (US$760m) every year.
Comparing root DNA
Scientists set out to determine why some grapevines accumulate salt and others do not. They found a mutation in a sodium transport protein in certain grapevine roots.
“By comparing the DNA of different grapevines we identified a specific gene that is associated with sodium exclusion from shoots,” said co-first author Dr Jake Dunlevy from CSIRO (Commonwealth Scientific and Industrial Research Organisation) Agriculture and Food.
“This discovery has allowed us to develop genetic markers that are being used to breed more salt-tolerant grapevine rootstocks, allowing new genotypes to be screened at the seedling stage rather than through lengthy and expensive field-based vineyard trials.”
Winegrape rootstocks have traditionally been developed in the US and Europe, and the new research will help develop robust rootstocks specifically for Australian conditions.
The research, published in New Phytologist this week, was carried out by scientists from the ARC Centre of Excellence in Plant Energy Biology at the University of Adelaide and CSIRO Agriculture and Food; and funded by Wine Australia.
Functional differences in transport properties of natural HKT1;1 variants influence shoot Na+ exclusion in grapevine rootstocks. Henderson, S. W., Dunlevy, J. D., Wu, Y., Blackmore, D. H., Walker, R. R., Edwards, E. J., Gilliham, M. and Walker, A. R. (2017).
New Phytol. doi:10.1111/nph.14888