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

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