Salinity Effects on Potassium Accumulation and Transporters Expression in Grape (Vitis vinifera L.)

Hydroponically grown ten grape genotypes (Vitis vinifera L.) were treated with different concentrations of NaCl. Chawga genotype accumulated K+ in its root and shoot even at high salinity. The correlation between Na+ and K+ concentrations in root and lamina of all genotypes was negative (P<0.05, r2=-0.841) except for Chawga (P<0.01, r2=0.998). Km calculated for K+ and Na+ uptake into root and shoot of Chawga showed that K+ and Na+ compete to enter the plant, especially through roots. Chawga accumulated K+ in plant parts in spite of external higher Na+ due to increasing salinity. Two KUP/KT/HAK-type potassium transporters are expressed highly in the grapevine during stress. VvK1.1 could play a major role in K+ loading into grape tissues. Under salinity stress the expression of VvKUP1 and VvKUP2 transporter and VvK1.1 channel increased significantly (P<0.05) in roots and leaves of Chawga genotype, but that increase was higher in roots than in leaves.