Wheat potassium transporter TaHAK13 mediates K absorption and maintains potassium homeostasis under low potassium stress.

Potassium (K) is an essential nutrient for plant physiological processes. Members of the HAK/KUP/KT gene family act as potassium transporters, and the family plays an important role in potassium uptake and utilization in plants. In this study, the gene was cloned from wheat and its function characterized. Real-time quantitative PCR (RT-qPCR) revealed that expression was induced by environmental stress and up-regulated under drought (PEG6000), low potassium (LK), and salt (NaCl) stress. GUS staining indicated that was mainly expressed in the leaf veins, stems, and root tips in , and expression varied with developmental stage. mediated K absorption when heterologously expressed in yeast CY162 strains, and its activity was slightly stronger than that of a positive control. Subcellular localization analysis illustrated that TaHAK13 was located to the plasma membrane. When c(K) ≤0.01 mM, the root length and fresh weight of transgenic lines (, Col) were significantly higher than those of non-transgenic lines (, Col). Non-invasive micro-test technology (NMT) indicated that the net K influx of the transgenic lines was also higher than that of the non-transgenic lines. This suggests that promotes K absorption, especially in low potassium media. Membrane-based yeast two-hybrid (MbY2H) and luciferase complementation assays (LCA) showed that TaHAK13 interacted with TaNPF5.10 and TaNPF6.3. Our findings have helped to clarify the biological functions of TaHAK13 and established a theoretical framework to dissect its function in wheat.