Potassium Transport and Signaling in Higher Plants

As one of the most important mineral nutrient elements, potassium (K⁺) participates in many plant physiological processes and determines the yield and quality of crop production. In this review, we summarize K⁺ signaling processes and K⁺ transport regulation in higher plants, especially in plant responses to K⁺-deficiency stress. Plants perceive external K⁺ fluctuations and generate the initial K⁺ signal in root cells. This signal is transduced into the cytoplasm and encoded as Ca²⁺ and reactive oxygen species signaling. K⁺-deficiency-induced signals are subsequently decoded by cytoplasmic sensors, which regulate the downstream transcriptional and posttranslational responses. Eventually, plants produce a series of adaptive events in both physiological and morphological alterations that help them survive K⁺ deficiency.