It is not all about sodium: revealing tissue specificity and signalling roles of potassium in plant responses to salt stress

• Published in: Plant and soil Vol. 431; no. 1/2; pp. 1 - 17
• Main Authors: Wu, Honghong, Zhang, Xianchen, Giraldo, Juan Pablo, Shabala, Sergey
• Format: Journal Article
• Language: English
• Published: Cham Springer 01.10.2018; Springer International Publishing; Springer Nature B.V
• Subjects: Abiotic stress; Agricultural production; Biomedical and Life Sciences; Botanical research; calcium; Calcium ions; Calcium signalling; Cellular signal transduction; Cellular stress response; Ecology; Environmental aspects; Life Sciences; MARSCHNER REVIEW; phloem; Physiological aspects; Plant Physiology; plant response; Plant Sciences; Potassium; Potassium (Nutrient); production technology; roots; Salinity; Salinity effects; Salt; salt stress; Salt stress (Botany); Salt tolerance; shoots; Sodium; Sodium (Nutrient); Soil salinity; Soil Science & Conservation; stress response; stress tolerance; Stresses; tonoplast; Transport; transporters; vacuoles; Xylem; Cell- and tissue- specificity; Programmed cell death; Signalling; Potassium homeostasis; Potassium channels and transporters; Potassium retention
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-018-3770-y

Background Salinity is a global issue threatening agricultural production systems across the globe. While the major focus of plant salinity stress tolerance research has been on sodium, the transport and physiological roles of K+ in plant salt stress response has received less attention. This review attempts to bridge this knowledge gap. Scope The major emphasis is on newly proposed K+ signalling roles and plant salt tolerance cell- and tissuespecificity. In addition to summarizing the importance of K+ retention for plant salt tolerance, we focus onaspects that were not the subject of previous reviews including (1) the importance of HAK/KUP family of transporters in K+ uptake in salt stressed plants and its possible linkage with Ca2+ and ROS signalling; (2) control of xylem K+ loading in salt stressed plants, control of phloem K+ recirculation in salt stressed plants and the potential importance of plant's ability to efficiently coordinate K+ signals between root and shoot; (3) the buffering capacity of the vacuolar K+ pool; and (4) mechanisms of restoring the basal cytosolic K+ levels by coordinated activity of tonoplast K+-permeable channels. Conclusions Overall, this review emphasises the need to fully understand the newly emerging roles of K+ and regulation of its transport for improving salinity stress tolerance in plants.