Expression of Na+/H+ antiporter gene in response to water and salinity stress in grapevine rootstocks

Grapevine rootstocks belonging to different species of Vitis differ in their response to stress. Vines of rootstocks 110R and 1613C were subjected to different salt and water stresses individually and in combination. Expression of VvNHX1, a Na⁺/H⁺ antiporter gene, was analyzed at 7 and 21 d of stress treatment. In 110R, the expression of VvNHX1 gene increased in response to both salinity and water stress already after 7 d. Under salinity and combined stress enhanced expression of this gene was observed also after 21 d whereas expression decreased under water stress. In 1613C, expression of this gene did not increase under salinity stress. There was delayed response to water and combined stress and expression increased several fold after 21 d of stress. The stressed vines of 110R maintained lower sodium content and higher K⁺/Na⁺ ratio as compared to rootstock 1613C.