AUTHOR=Run Yonghang , Cheng Xiyong , Dou Wei , Dong Yue , Zhang Yanan , Li Bingbing , Liu Tengfei , Xu Haixia 

TITLE=Wheat potassium transporter TaHAK13 mediates K+ absorption and maintains potassium homeostasis under low potassium stress

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1103235

DOI=10.3389/fpls.2022.1103235

ISSN=1664-462X

ABSTRACT=<p>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 <italic>TaHAK13</italic> gene was cloned from wheat and its function characterized. Real-time quantitative PCR (RT-qPCR) revealed that <italic>TaHAK13</italic> expression was induced by environmental stress and up-regulated under drought (PEG6000), low potassium (LK), and salt (NaCl) stress. GUS staining indicated that <italic>TaHAK13</italic> was mainly expressed in the leaf veins, stems, and root tips in <italic>Arabidopsis thaliana</italic>, and expression varied with developmental stage. <italic>TaHAK13</italic> mediated K<sup>+</sup> absorption when heterologously expressed in yeast  CY162 strains, and its activity was slightly stronger than that of a <italic>TaHAK1</italic> positive control. Subcellular localization analysis illustrated that TaHAK13 was located to the plasma membrane. When c(K<sup>+</sup>) ≤0.01 mM, the root length and fresh weight of <italic>TaHAK13</italic> transgenic lines (<italic>athak5/TaHAK13</italic>, Col<italic>/TaHAK13</italic>) were significantly higher than those of non-transgenic lines (<italic>athak5</italic>, 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 <italic>TaHAK13</italic> promotes K<sup>+</sup> 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.</p>