Arabidopsis Putative Selenium-Binding Protein1 Expression Is Tightly Linked to Cellular Sulfur Demand and Can Reduce Sensitivity to Stresses Requiring Glutathione for Tolerance
Arabidopsis Putative Selenium-Binding Protein1 Expression Is Tightly Linked to Cellular Sulfur Demand and Can Reduce Sensitivity to Stresses Requiring Glutathione for Tolerance
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DOI：
10.1104/pp.109.144808
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发表时间：
2009-10-01
期刊：
影响因子：
7.4
通讯作者：
Bourguignon, Jacques
中科院分区：
文献类型：
--
作者：
Hugouvieux, Veronique;Dutilleul, Christelle;Bourguignon, Jacques
利用表达荧光素酶（LUC）报告基因的转基因系，在SBP1启动子控制下，研究了硒结合蛋白1 （SBP1）基因在镉（Cd）、硒酸盐[Se(VI)]和亚硒酸盐[Se(IV)]}、铜（Cu）、锌（Zn）和过氧化氢（H2O2）胁迫下的拟南芥幼苗中的表达。在SBP1::LUC系的根和茎中，LUC活性对Cd、Se（VI）、Cu和H2O2的响应均有所增加，而对Se（IV）和Zn的响应则没有。SBP1的表达模式与PRH43相似，PRH43编码5'-腺苷酸磷酸硫酸还原酶2，这是诱导硫同化途径的标记物，表明硫需求的增强触发了SBP1的上调。与这些结果相关的是，SBP1启动子对硫饥饿的反应显示出增强的活性。给植株喂食谷胱甘肽（GSH）可消除SBP1的硫饥饿诱导，同时给幼苗添加抑制GSH合成的丁硫氨酸亚砜可增强SBP1的硫饥饿诱导，表明GSH水平参与了SBP1表达的调控。在Cd、Se（VI）和H2O2胁迫下，幼苗总谷胱甘肽水平发生了变化。因此，受GSH合成影响的cad2-1幼苗比野生型植物对这三种胁迫更为敏感。此外，过表达SBP1的野生型和cad2-1幼苗除了对Cd的抗性外，还表现出对Se（VI）和H2O2的耐受性显著增强，这表明SBP1的表达降低了对需要GSH来产生耐受性的胁迫的敏感性。这些结果对SBP1在植物中的潜在调控和功能进行了讨论。
Selenium-Binding Protein1 (SBP1) gene expression was studied in Arabidopsis (Arabidopsis thaliana) seedlings challenged with several stresses, including cadmium (Cd), selenium {selenate [Se(VI)] and selenite [Se(IV)]}, copper (Cu), zinc (Zn), and hydrogen peroxide (H2O2) using transgenic lines expressing the luciferase (LUC) reporter gene under the control of the SBP1 promoter. In roots and shoots of SBP1::LUC lines, LUC activity increased in response to Cd, Se(VI), Cu, and H2O2 but not in response to Se(IV) or Zn. The pattern of expression of SBP1 was similar to that of PRH43, which encodes the 5'-Adenylylphosphosulfate Reductase2, a marker for the induction of the sulfur assimilation pathway, suggesting that an enhanced sulfur demand triggers SBP1 up-regulation. Correlated to these results, SBP1 promoter showed enhanced activity in response to sulfur starvation. The sulfur starvation induction of SBP1 was abolished by feeding the plants with glutathione (GSH) and was enhanced when seedlings were treated simultaneously with buthionine sulfoxide, which inhibits GSH synthesis, indicating that GSH level participates in the regulation of SBP1 expression. Changes in total GSH level were observed in seedlings challenged with Cd, Se(VI), and H2O2. Accordingly, cad2-1 seedlings, affected in GSH synthesis, were more sensitive than wild-type plants to these three stresses. Moreover, wild-type and cad2-1 seedlings overexpressing SBP1 showed a significant enhanced tolerance to Se(VI) and H2O2 in addition to the previously described resistance to Cd, highlighting that SBP1 expression decreases sensitivity to stress requiring GSH for tolerance. These results are discussed with regard to the potential regulation and function of SBP1 in plants.