A novel fluorescence imaging approach to monitor salt stress-induced modulation of ouabain-sensitive ATPase activity in sunflower seedling roots
A novel fluorescence imaging approach to monitor salt stress-induced modulation of ouabain-sensitive ATPase activity in sunflower seedling roots
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DOI：
10.1111/ppl.12101
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发表时间：
2014-04-01
影响因子：
6.4
通讯作者：
Bhatla, Satish Chander
中科院分区：
文献类型：
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作者：
Mukherjee, Soumya;Bhatla, Satish Chander
幼苗暴露于盐胁迫下，预计会通过多种机制显示胞内钠离子积累的调节。利用一种新的方法，本研究证实了盐胁迫（120 mM NaCl）下向日葵幼苗根部对乌巴因（OU）敏感的atp酶活性。利用9-Anthroylouabain（已知能抑制动物系统中Na+，K+- atp酶活性的一种瓦巴因衍生物，EC 3.6.3.9）作为探针，利用共聚焦激光扫描显微镜对向日葵（Helianthus annuus）幼苗根部的ou敏感atp酶活性进行荧光光谱估计和定位。盐胁迫48 h可显著诱导幼苗根分生组织区域的ou敏感atp酶活性。钙离子（10 mM）显著抑制酶活性，钠离子在小柱细胞、表皮和根分生组织区细胞的胞浆中平行积累。作为对NaCl胁迫的快速反应，ou敏感型atp酶的活性定位于根原生质体核膜，并在钙离子处理后受到抑制。核膜定位的ou敏感atp酶活性突出了钠离子从细胞核外排的可能机制。因此，通过一种新的方法在植物系统中证明了ou敏感的atp酶活性、钙离子对其的调节和幼苗根系各区域钠离子的积累之间的相关性。
Seedlings exposed to salt stress are expected to show modulation of intracellular accumulation of sodium ions through a variety of mechanisms. Using a new methodology, this work demonstrates ouabain (OU)-sensitive ATPase activity in the roots of sunflower seedlings subjected to salt stress (120 mM NaCl). 9-Anthroylouabain (a derivative of ouabain known to inhibit Na+,K+-ATPase activity in animal systems, EC 3.6.3.9) has been used as a probe to analyze OU-sensitive ATPase activity in sunflower (Helianthus annuus) seedling roots by spectrofluorometric estimation and localization of its spatial distribution using confocal laser scanning microscopy. Salt stress for 48 h leads to a significant induction of OU-sensitive ATPase activity in the meristematic region of the seedling roots. Calcium ions (10 mM) significantly inhibit enzyme activity and a parallel accumulation of sodium ions in the cytosol of the columella cells, epidermis and in the cells of the meristematic region of the roots is evident. As a rapid response to NaCl stress, the activity of OU-sensitive ATPase gets localized in the nuclear membrane of root protoplasts and it gets inhibited after treatment with calcium ions. Nuclear membrane localization of the OU-sensitive ATPase activity highlights a possible mechanism to efflux sodium ions from the nucleus. Thus, a correlation between OU-sensitive ATPase activity, its modulation by calcium ions and accumulation of sodium ions in various regions of the seedling roots, has been demonstrated using a novel approach in a plant system.