title: Regulation of potassium transport in plants under hostile conditions: implications for abiotic and biotic stress tolerance.
abstract: Intracellular potassium homeostasis is a prerequisite for the optimal operation of plant metabolic machinery and plant's overall performance. It is controlled by K(+) uptake, efflux and intracellular and long-distance relocation, mediated by a large number of K(+) -selective and non-selective channels and transporters located at both plasma and vacuolar membranes. All abiotic and biotic stresses result in a significant disturbance to intracellular potassium homeostasis. In this work, we discuss molecular mechanisms and messengers mediating potassium transport and homeostasis focusing on four major environmental stresses: salinity, drought, flooding and biotic factors. We argue that cytosolic K(+) content may be considered as one of the 'master switches' enabling plant transition from the normal metabolism to 'hibernated state' during first hours after the stress exposure and then to a recovery phase. We show that all these stresses trigger substantial disturbance to K(+) homeostasis and provoke a feedback control on K(+) channels and transporters expression and post-translational regulation of their activity, optimizing K(+) absorption and usage, and, at the extreme end, assisting the programmed cell death. We discuss specific modes of regulation of the activity of K(+) channels and transporters by membrane voltage, intracellular Ca(2+) , reactive oxygen species, polyamines, phytohormones and gasotransmitters, and link this regulation with plant-adaptive responses to hostile environments.
authors: School of Agricultural Science, University of Tasmania, Hobart, Tas, 7001, Australia.
authors: Sergey
authors: S
authors: Shabala
authors: Igor
authors: I
authors: Pottosin
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology; D017136:Ion Transport; D008954:Models, Biological; D010944:Plants / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000502:physiology; D027961:Potassium-Hydrogen Antiporters / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D015221:Potassium Channels; D027961:Potassium-Hydrogen Antiporters; D011188:Potassium; D002118:Calcium