Keeping the salt out of grapes

New research published in New Phytologist points the way towards the breeding of salt tolerant grapevines that are likely to improve the sustainability of the Australian wine sector.

With funding from Wine Australia, a team of scientists from the ARC Centre of Excellence in Plant Energy Biology at the University of Adelaide and CSIRO Agriculture and Food identified genes expressed in grapevine roots that limit the amount of sodium that reaches the berries and leaves.

“Berries that contain too much sodium may be unsuitable for wine production and this can lead to vineyards remaining unpicked, resulting in financial losses for vineyard owners,” said Dr Sam Henderson, co-first author of the study, from the University of Adelaide.

The research team set out to determine why some grapevines accumulate salt while others don’t, and found a specific mutation in a sodium transport protein in grapevine roots. The mutation stops the protein from working effectively, leading to more salt leaking into the shoots of vines – and ultimately the grapes – from the soil.

Image: grapevine. Image credit: Ewen Bell / Wine Australia.
Image credit: Ewen Bell / Wine Australia

Low levels of salt can actually improve the flavour of wine, but an excess of it can lead to unpalatable taste, reduce grape yield, and damage the long-term health of grapevines – a problem experienced in wine-producing regions around the world. In Australia, issues caused by excess salinity have been estimated to cost more than $1 billion each year.

“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.

“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.”

“Traditionally, winegrape rootstocks have been developed in wine producing regions in the United States and Europe. This new research supports a breeding program to combine multiple beneficial traits in grapevines using conventional breeding,” said Dr Liz Waters, Wine Australia’s General Manager for Research, Development and Extension. Dr Waters explained that developing robust rootstocks specifically for Australian conditions would support the local wine sector’s sustainability well into the future.

The research was led by Dr Mandy Walker, CSIRO, and Professor Matthew Gilliham, University of Adelaide, who are continuing to collaborate on additional factors that will further improve grapevine salt tolerance, such as the exclusion of chloride.

Adapted from a press release.

Read the paper: Henderson, S. W., Dunlevy, J. D., Wu, Y., Blackmore, D. H., Walker, R. R., Edwards, E. J., Gilliham, M. and Walker, A. R. (2017) Functional differences in transport properties of natural HKT1;1 variants influence shoot Na+ exclusion in grapevine rootstocks. New Phytologist. doi: 10.1111/nph.14888


 

Mike Whitfield (@mgwhitfield)
Development Coordinator
New Phytologist