Over-expression of ApKUP3 enhances potassium nutrition and drought tolerance in transgenic rice

ApKUPs are typical high-affinity potassium (K+) transporters of Alternanthera philoxeroides which are involved in its response to K+ starvation and abiotic stresses. In this study, the overexpression of ApKUP3 gene in rice resulted in enhanced K+ nutrition and drought tolerance of transgenic plants. Compared with wild-type (WT) plants, the transgenic plants showed a better growth performance and a strengthened K+ accumulation under different K+ supplies. The ApKUP3 overexpression in the rice plants also enhanced tolerance to a drought stress, as evidenced by a reduced leaf water loss and an increased total leaf chlorophyll content, stomatal conductance, net photosynthetic rate, and activities of superoxide dismutase, peroxidase, and ascorbate peroxidase (APX). Moreover, the transcription of genes involved in the antioxidation defense system were higher in the transgenic plants than in the WT plants upon the drought stress.