Referenced in: none

Automatically associated channels: Slo1

Title: H(2)O(2) and cytosolic Ca(2+) signals triggered by the PM H(+)-coupled transport system mediate K(+)/Na(+) homeostasis in NaCl-stressed Populus euphratica cells.

Authors: Jian Sun, Mei-Juan Wang, Ming-Quan Ding, Shu-Rong Deng, Mei-Qin Liu, Cun-Fu Lu, Xiao-Yang Zhou, Xin Shen, Xiao-Jiang Zheng, Zeng-Kai Zhang, Jin Song, Zan-Min Hu, Yue-Xu, Shao-Liang Chen

Journal, date & volume: , 2010 Jan 15 , ,

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/20082667

Abstract
Using confocal microscopy, X-ray microanalysis and the scanning ion-selective electrode technique, we investigated the signalling of H(2)O(2), cytosolic Ca(2+) ([Ca(2+)](cyt)) and the PM H(+)-coupled transport system in K(+)/Na(+) homeostasis control in NaCl-stressed calluses of Populus euphratica. An obvious Na(+)/H(+) antiport was seen in salinized cells; however, NaCl stress caused a net K(+) efflux, because of the salt-induced membrane depolarization. H(2)O(2) levels, regulated upwards by salinity, contributed to ionic homeostasis, because H(2)O(2) restrictions by DPI or DMTU caused enhanced K(+) efflux and decreased Na(+)/H(+) antiport activity. NaCl induced a net Ca(2+) influx and a subsequent rise of [Ca(2+)](cyt), which is involved in H(2)O(2)-mediated K(+)/Na(+) homeostasis in salinized P. euphratica cells. When callus cells were pretreated with inhibitors of the Na(+)/H(+) antiport system, the NaCl-induced elevation of H(2)O(2) and [Ca(2+)](cyt) was correspondingly restricted, leading to a greater K(+) efflux and a more pronounced reduction in Na(+)/H(+) antiport activity. Results suggest that the PM H(+)-coupled transport system mediates H(+) translocation and triggers the stress signalling of H(2)O(2) and Ca(2+), which results in a K(+)/Na(+) homeostasis via mediations of K(+) channels and the Na(+)/H(+) antiport system in the PM of NaCl-stressed cells. Accordingly, a salt stress signalling pathway of P. euphratica cells is proposed.