ION TRANSPORT GENES MAY BE RELATED TO GRAPEVINE SHOOT CHOLIDE EXCLUSION AND SALT TOLERANCE
Salt tolerance in grapevine is associated with shoot chloride (Cl-)
exclusion in shoots. Despite the knowledge of Cl exclusion in grapevine, the
mechanism of this process has remained elusive. To search for candidate
that control Cl exclusion, researchers led by Matthew Gilliham of the
University of Adelaide in Australia compared three Vitis spp. with
contrasting shoot Cl exclusion capacities using custom microarray.
Under 50mM Cl- conditions, the genotypes 140 Ruggeri (shoot Cl- excluding
rootstock), K51-40 (shoot Cl- including rootstock) and Cabernet Sauvignon
(intermediate shoot Cl- excluder) showed different transcriptional changes
in their roots. The level of change was found to be correlated with the
amount of Cl- accumulated in shoots. Despite these differences, no Cl-
transporters were identified. However, under control conditions, genes for
putative ion channels as well as members of NRT1 and CLC families were
differentially expressed between rootstocks.
Results show that the Cl- exclusion mechanism in grapevine are not
stress-inducible, but are constitutively different between varieties. The
team has identified individual genes from large families known for anion
transport as likely candidates for Cl- exclusion in Vitis species.