Stress-induced electrolyte leakage: the role of K+-permeable channels and involvement in programmed cell death and metabolic adjustment

Abstract

Electrolyte leakage accompanies plant response to stresses, such as salinity, pathogen attack, drought, heavy metals, hyperthermia, and hypothermia; however, the mechanism and physiological role of this phenomenon have only recently been clarified. Accumulating evidence shows that electrolyte leakage is mainly related to K(+) efflux from plant cells, which is mediated by plasma membrane cation conductances. Recent studies have demonstrated that these conductances include components with different kinetics of activation and cation selectivity. Most probably they are encoded by GORK, SKOR, and annexin genes. Hypothetically, cyclic nucleotide-gated channels and ionotropic glutamate receptors can also be involved. The stress-induced electrolyte leakage is usually accompanied by accumulation of reactive oxygen species (ROS) and often results in programmed cell death (PCD). Recent data strongly suggest that these reactions are linked to each other. ROS have been shown to activate GORK, SKOR, and annexins. ROS-activated K(+) efflux through GORK channels results in dramatic K(+) loss from plant cells, which stimulates proteases and endonucleases, and promotes PCD. This mechanism is likely to trigger plant PCD under severe stress. However, in moderate stress conditions, K(+) efflux could play an essential role as a 'metabolic switch' in anabolic reactions, stimulating catabolic processes and saving 'metabolic' energy for adaptation and repair needs.

Cell-Type-Specific H+-ATPase Activity in Root Tissues Enables K+ Retention and Mediates Acclimation of Barley (Hordeum vulgare) to Salinity Stress

“…Consistent with previous observations, the OH $ -induced current was biphasic, composed of the instantaneous and the time-dependent depolarization-activated components (Fig. 6A), which could be tentatively assigned to ROS-activated NSCC and GORK, respectively (Demidchik et al, 2014;Shabala and Pottosin, 2014). Due to a strong outward rectification, a reversal potential of the time-dependent current could not be defined unequivocally; instantaneous currents reversed around 230 mV (i.e.…”

A comparison of the effects of 1,4-naphthoquinone and 2-hydroxy-1,4-naphthoquinone (lawsone) on indole-3-acetic acid (IAA)-induced growth of maize coleoptile cells

“…It is also possible that ROS-induced cytosol Ca 2+ elevations (reviewed in Mori and Schroeder 2004), in turn, can inhibit PM H + -ATPase activity (Brault et al 2004;Kinoshita et al 1995;Polevoi et al 1996), and depolarise plasma membrane potential (Trouverie et al 2008). It can be also speculated that the inhibition of IAA-induced growth may also be caused by an ROS-induced K + efflux, which results in a dramatic K + loss from plant cells (reviewed in Demidchik et al 2014). Here, the suggestion that NQ and NQ-2-OH inhibit PM H + -ATPase is supported by four pieces of evidence: (1) the inhibition of IAA-induced proton extrusion by both naphthoquinones (excluding NQ at 1 µM, Fig.…”

Boron Supply and Water Deficit Consequences in Young Paricá (<i>Schizolobium parahyba</i> var.<i> amazonicum</i>) Plants

“…This occurred due to an increase in H2O2, resulting in membrane disturbs and release of electrolytes, with consequent reduction in permeability of the cell membrane (GonzalezMendoza et al, 2009;Demidchik et al, 2014;Langaro et al, 2014). Masoumi et al (2010) observed an increase in EL in Kochia scoparia leaves, corroborating with the data of this study.…”