胡楊細(xì)胞在鹽脅迫下與K+/Na+動(dòng)態(tài)平衡調(diào)控相關(guān)的信號通路研究

    近日，北京林業(yè)大學(xué)生物科學(xué)與技術(shù)學(xué)院陳少良實(shí)驗(yàn)室利用取得的科研成果在《Plant, Cell & Environment》（2008 IF 4.666）雜志發(fā)表。這項(xiàng)成果將非損傷微測技術(shù)與激光共聚焦、X射線微量分析等技術(shù)相結(jié)合，研究了胡楊細(xì)胞在鹽脅迫下與K⁺/Na⁺動(dòng)態(tài)平衡調(diào)控相關(guān)的信號通路，發(fā)現(xiàn)質(zhì)膜H⁺偶聯(lián)轉(zhuǎn)運(yùn)體（PM H⁺-coupled transport system）可以激發(fā)H₂O₂及胞質(zhì)Ca²⁺信號，進(jìn)而通過調(diào)節(jié)K⁺通道及Na⁺/H⁺反向轉(zhuǎn)運(yùn)體調(diào)控K⁺/Na⁺動(dòng)態(tài)平衡。非損傷微測技術(shù)在本研究中是獲得離子跨膜流動(dòng)信息的必不可少的工具。
      陳少良實(shí)驗(yàn)室在一年多時(shí)間里利用非損傷微測技術(shù)已經(jīng)連續(xù)發(fā)表三篇高水平的研究論文，達(dá)到甚至超過國外相同領(lǐng)域的科研水平，躋身世界一流實(shí)驗(yàn)室行列。該實(shí)驗(yàn)室已經(jīng)積累了應(yīng)用非損傷微測技術(shù)的豐富經(jīng)驗(yàn)，培養(yǎng)出以本文第一作者孫健（也是前兩篇研究論文的第一作者）為代表的一批熟練掌握非損傷微測技術(shù)的優(yōu)秀學(xué)子，相信不久還會有大量的優(yōu)質(zhì)成果誕生。

ABSTRACT:

Using confocal microscopy, X-ray microanalysis and the scanning ion-selective electrode technique, we investigated the signalling of H₂O₂, cytosolic Ca²⁺ ([Ca2+]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. H₂O₂ levels, regulated upwards by salinity, contributed to ionic homeostasis,because H₂O₂ restrictions by DPI or DMTU caused enhanced K⁺ efflux and decreased Na⁺ /H⁺ antiport activity. NaCl induced a net Ca²⁺ influx and a subsequent rise of [Ca²⁺]cyt, which is involved in H2O2-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 H₂O₂ and [Ca²⁺]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 H₂O₂ and Ca²⁺, 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.