Zinc Resistance Mechanisms of P1B-type ATPases in Sinorhizobium meliloti CCNWSX0020.
Zinc Resistance Mechanisms of P1B-type ATPases in Sinorhizobium meliloti CCNWSX0020.
复制标题
苜蓿中华根瘤菌P-1B型ATP酶的锌抗性机制CCNWSX0020
DOI：
10.1038/srep29355
复制
发表时间：
2016-07-05
影响因子：
4.6
通讯作者：
Wei G
中科院分区：
文献类型：
--
作者：
Lu M;Li Z;Liang J;Wei Y;Rensing C;Wei G
紫花苜蓿中华根瘤菌CCNWSX0020菌株表现出对多种金属高水平暴露的耐受性，以及对生长在金属污染土壤中的豆科植物的生长促进作用。然而，耐金属菌株的机制仍不清楚。我们利用5个缺失的P1B-ATPase，分别命名为∆CopA1b、∆FixI1、∆CopA3、∆ZNTA和∆NIA，研究了P1B-ATPase在紫花苜蓿对重金属抗性中的作用。∆coPA1b和∆zntA突变体对锌、镉和铅都有不同程度的敏感，而其他突变体对金属抗性没有显著影响。此外，锌、镉、铅可诱导ZNTA的表达，而铜、银可诱导COPA1b的表达。这两个缺失可以导致细胞内锌、铅和镉浓度的增加，但不会导致铜的浓度增加。∆CopA1b和∆zntA突变体的互补在一定程度上恢复了植株对锌、镉、铅的耐性。综上所述，这些结果表明，在CCNWSX0020中，coA1b和zntA在锌的动态平衡和Cd、Pd的解毒中起着重要的作用。
The Sinorhizobium meliloti (S. meliloti) strain CCNWSX0020 displayed tolerance to high levels exposures of multiple metals and growth promotion of legume plants grown in metal-contaminated soil. However, the mechanism of metal-resistant strain remains unknown. We used five P1B-ATPases deletions by designating as ∆copA1b, ∆fixI1, ∆copA3, ∆zntA and ∆nia, respectively to investigate the role of P1B-ATPases in heavy metal resistance of S. meliloti. The ∆copA1b and ∆zntA mutants were sensitive to zinc (Zn), cadmium (Cd) and lead (Pb) in different degree, whereas the other mutants had no significant influence on the metal resistance. Moreover, the expression of zntA was induced by Zn, Cd and Pb whereas copA1b was induced by copper (Cu) and silver (Ag). This two deletions could led to the increased intracellular concentrations of Zn, Pb and Cd, but not of Cu. Complementation of ∆copA1b and ∆zntA mutants showed a restoration of tolerance to Zn, Cd and Pb to a certain extent. Taken together, the results suggest an important role of copA1b and zntA in Zn homeostasis and Cd and Pb detoxification in S. meliloti CCNWSX0020.