Induction of high-affinity NO3- uptake in grapevine roots is an active process correlated to the expression of specific members of the NRT2 and plasma membrane H+-ATPase gene families.

ABSTRACT

The phenomenon of NO3- induction in plant roots has been characterised both in herbaceous and woody plants. Grapevine (Vitis vinifera L.) plants, hydroponically grown, showed an increase in NO3- uptake rate in response to anion treatment for different periods in the nutrient solution after 1 week of NO3- deprivation. The expression profile of the two high-affinity NO3- transporters VvNRT2.4A and VvNRT2.4B, and the gene encoding the accessory protein VvNAR2.2 exhibits a similar trend to that of the anion uptake. The induction, also involving the increase in activity and protein levels of plasma membrane H+-ATPase, is correlated with the expression profile of two (VvHA2 and VvHA4) out of eight putative plasma membrane H+-ATPase genes identified in grapevine genome.