Regulation of potassium transport and signaling in plants

•K+ channels and transporters are involved in diverse physiological processes.•Plants can sense external K+ deficiency and generate low-K+ signals in plant cells.•The transcription of many K+ transporter genes are induced by low-K+ stress.•Phosphorylation is crucial for the regulation of both K+ channels and transporters.•Coordination of K+/NO3− absorption and translocation is necessary for plants. As an essential macronutrient, potassium (K+) plays crucial roles in diverse physiological processes during plant growth and development. The K+ concentration in soils is relatively low and fluctuating. Plants are able to perceive external K+ changes and generate chemical and physical signals in plant cells. The signals can be transducted across the plasma membrane and into the cytosol, and eventually regulates the downstream targets, particularly K+ channels and transporters. As a result, K+ homeostasis in plant cells is modulated, which facilitates plant adaptation to K+ deficient conditions. This minireview focuses on the latest research progress in the diverse functions of K+ channels and transporters as well as their regulatory mechanisms in plant response to low-K+ stress.