The Sweet Potato K + Transporter IbHAK11 Regulates K + Deficiency and High Salinity Stress Tolerance by Maintaining Positive Ion Homeostasis.

The K transporter KT/HAK/KUP (K transporter/high-affinity K/K uptake) family has a critical effect on K uptake and translocation in plants under different environmental conditions. However, the functional analysis of KT/HAK/KUP members in sweet potatoes is still limited. The present work reported the physiological activity of a new gene, , in the KT/HAK/KUP family in sweet potatoes. expression increased significantly in the low K-tolerant line compared with the low K-sensitive line following treatment with low K concentrations. upregulation promoted root growth in under low K conditions. Under high saline stress, transgenic lines had superior growth and photosynthetic characteristics compared with the wild-type (WT). As for -overexpressing plants, activation of both the non-enzymatic and enzymatic reactive oxygen species (ROS) scavenging systems was observed. Therefore, -overexpressing plants had lower malondialdehyde (MDA) and ROS levels (including HO and O) compared with WT under salt-induced stress. We also found that under both low K and high salinity conditions, overexpression of enhanced K translocation from the root to the shoot and decreased Na absorption in . Consequently, IbHAK11 positively regulated K deficiency and high salinity stresses by regulating K translocation and Na uptake, thus maintaining K/Na homeostasis in plants.