MAN3 gene regulates cadmium tolerance through the glutathione-dependent pathway in Arabidopsis thaliana
MAN3 gene regulates cadmium tolerance through the glutathione-dependent pathway in Arabidopsis thaliana
复制标题
拟南芥中MAN3基因通过谷胱甘肽依赖性途径调节镉耐受性
DOI：
10.1111/nph.13101
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发表时间：
2015-01-01
期刊：
影响因子：
9.4
通讯作者：
Cao, Shuqing
中科院分区：
文献类型：
--
作者：
Chen, Jian;Yang, Libo;Cao, Shuqing
土壤重金属镉（Cd）污染是一个全球性的环境问题。谷胱甘肽（GSH）依赖的植物螯合素（PC）合成途径是植物对镉积累和耐性的重要机制之一。然而，对这一途径的调控知之甚少。在此，我们鉴定了拟南芥镉耐受显性突变体xcd 1-D（XVE系统诱导的镉耐受1），并克隆了编码内切甘露聚糖酶的XCD 1基因（以前称为MAN 3）。MAN 3的过表达增强了镉的积累和耐性，而MAN 3的功能缺失则降低了镉的积累和耐性。在雌二醇的存在下，增强镉积累和耐受性xcd 1-D与GSH依赖，镉激活的合成的PC，这与协调激活的基因表达。镉胁迫诱导MAN 3的表达，从而增加甘露聚糖酶活性，导致细胞壁中甘露糖含量增加。此外，甘露糖处理不仅挽救了xcd 1 -2突变体的镉敏感表型，但也提高了野生型植物的镉耐受性。值得注意的是，这种甘露糖介导的镉积累和耐受性是依赖于GSH依赖PC浓度通过协调控制参与PC合成的基因的表达。我们的研究结果表明，MAN 3调节GSH依赖的PC合成途径，有助于镉的积累和耐受性在A。通过协调控制基因的表达。
Pollution of soil by the heavy metal cadmium (Cd) is a global environmental problem. The glutathione (GSH)-dependent phytochelatin (PC) synthesis pathway is one of the most important mechanisms contributing to Cd accumulation and tolerance. However, the regulation of this pathway is poorly understood. Here, we identified an Arabidopsis thaliana cadmium-tolerant dominant mutant xcd1-D (XVE system-induced cadmium-tolerance 1) and cloned XCD1 gene (previously called MAN3), which encodes an endo--mannanase. Overexpression of MAN3 led to enhanced Cd accumulation and tolerance, whereas loss-of-function of MAN3 resulted in decreased Cd accumulation and tolerance. In the presence of estradiol, enhanced Cd accumulation and tolerance in xcd1-D was associated with GSH-dependent, Cd-activated synthesis of PCs, which was correlated with coordinated activation of gene expression. Cd stress-induced expression of MAN3 and the consequently increased mannanase activity, led to increased mannose content in cell walls. Moreover, mannose treatment not only rescued the Cd-sensitive phenotype of the xcd1-2 mutant, but also improved the Cd tolerance of wild-type plants. Significantly, this mannose-mediated Cd accumulation and tolerance is dependent on GSH-dependent PC concentrations via coordinated control of expression of genes involved in PC synthesis. Our results suggest that MAN3 regulates the GSH-dependent PC synthesis pathway that contributes to Cd accumulation and tolerance in A. thaliana by coordinated control of gene expression.