Cloning of sorghum HKT genes and their function validation in Arabidopsis

Three sorghum high affinity potassium transporter genes, SbHKT1;4, SbHKT1;5 and SbHKT2;1, were cloned and constitutively expressed in Arabidopsis hkt1-1 mutant, respectively, and the tolerance to salt and drought of the transgenic lines analyzed. Upon high Na⁺ stress, the growth of all transgenic lines was inhibited, and this phenotype could be obviously alleviated when adequate K+ was added. After water stress, we found that transgenic lines were more tolerant to drought than athkt1-1 mutant line. These results indicated that SbHKTs not only played a role in tolerance to salt stress, but also exerted significant function in the presence of drought-stress.