Functional characterization of cadmium-responsive garlic gene AsMT2b: A new member of metallothionein family
Functional characterization of cadmium-responsive garlic gene AsMT2b: A new member of metallothionein family
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DOI：
10.1007/s11434-006-0409-9
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发表时间：
2006-02
影响因子：
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通讯作者：
Haiyan Zhang;Wenzhong Xu;Wentao Dai;Zhenyan He;Mi Ma
中科院分区：
文献类型：
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作者：
Haiyan Zhang;Wenzhong Xu;Wentao Dai;Zhenyan He;Mi Ma
利用RACE方法从大蒜幼苗中克隆了一个金属硫蛋白（MT）家族的新基因，命名为AsMT 2b。AsMT 2b基因cDNA全长520 bp，编码80个氨基酸。氨基酸序列分析表明，AsMT 2b具有2型MT蛋白的特征结构，但其N端和C端半胱氨酸残基的数目和排列与其它2型MT蛋白不同。半定量逆转录酶-PCR显示，AsMT 2b的转录水平仅随着镉浓度的升高或孵育时间的延长而增强。AsMT 2b的这种表达模式与其他2型MT基因的表达模式有很大不同。用该基因转化的酵母细胞对镉的抗性有所提高。与野生型相比，AsMT 2b过表达拟南芥表现出更强的镉耐性和更高的镉积累。这些结果表明，AsMT 2b在Cd污染土壤的植物修复中具有重要的应用前景。
A new gene of metallothionein (MT) family was cloned from garlic (Allium sativum) seedlings using RACE method and designated AsMT2b. The full length of AsMT2b cDNA was 520 bp encoding 80 amino acids. The deduced amino acids of AsMT2b showed that AsMT2b contained the characteristic structure of type 2 MT proteins, but the number and arrangement of the cysteine residues in the N-and C-terminal domains was different from other type 2 MT proteins. Semi-quantitative reverse transcriptase-PCR showed that transcript levels of AsMT2b were enhanced only in response to higher concentrations or longer incubation time of Cd. Such an expression pattern of AsMT2b greatly differed from that of other type 2 MT genes. Yeast cells transformed with this gene had improved resistance to Cd. AsMT2b overexpressing Arabidopsis showed stronger Cd tolerance and higher Cd accumulation compared with wild-type plants. These results suggest that AsMT2b should be useful in phytoremediation of Cd-polluted soil in the future.