A tonoplast-localized half-size ABC transporter is required for internal detoxification of aluminum in rice
A tonoplast-localized half-size ABC transporter is required for internal detoxification of aluminum in rice
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DOI：
10.1111/j.1365-313x.2011.04837.x
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发表时间：
2012-03-01
期刊：
影响因子：
7.2
通讯作者：
Ma, Jian Feng
中科院分区：
文献类型：
--
作者：
Huang, Chao-Feng;Yamaji, Naoki;Ma, Jian Feng
有毒的铝迅速进入根细胞，因此需要内部解毒。然而，这一过程的分子机制知之甚少。在这里，我们功能上的特点，水稻基因，Os03g0755100（OsALS1），这是由ART1，C2H2型锌指转录因子调控。OsALS1编码一半大小的ABC转运蛋白，其是TAP（与抗原加工相关的转运蛋白）亚组的成员。铝诱导OsALS1在根中快速特异表达，而其他金属或低pH不诱导表达。OsALS1定位于根的所有细胞。此外，OsALS1定位于液泡膜。这些表达模式和定位的细胞特异性不同于拟南芥中的同源基因AtALS1。OsALS1基因敲除后，三个独立株系对铝的敏感性显著提高，但对其他金属和低pH的敏感性没有影响。野生型和OsALS1突变体之间铝积累模式的比较表明，野生型和突变体根尖细胞液中铝水平没有差异，但突变体在细胞质和细胞核中积累的铝比野生型多。OsALS1在酵母中的表达由于错误定位而导致Al敏感性增加。这些结果表明，OsALS1定位在液泡膜负责螯合铝进入液泡，这是需要的内部解毒铝在水稻。
Toxic aluminum enters the root cells rapidly, therefore internal detoxification is required. However, the molecular mechanisms underlying this process are poorly understood. Here we functionally characterized a rice gene, Os03g0755100 (OsALS1), that is regulated by ART1, a C2H2-type zinc finger transcription factor. OsALS1 encodes a half-size ABC transporter that is a member of the TAP (transporter associated with antigen processing) sub-group. Expression of OsALS1 was rapidly and specifically induced by Al in the roots, but not by other metals or low pH. OsALS1 was localized at all cells of the roots. Furthermore, OsALS1 is localized to the tonoplast. These expression patterns and cell specificity of localization are different from those of the homologous gene AtALS1 in Arabidopsis. Knockout of OsALS1 in three independent lines resulted in significant increased sensitivity to Al, but did not affect the sensitivity to other metals and low pH. Comparison of Al accumulation patterns between wild-type and osals1 mutants showed that there was no difference in Al levels in the cell sap of root tips between wild-type and the mutants, but the mutants accumulated more Al in the cytosol and nucleus than the wild-type. Expression of OsALS1 in yeast resulted in increased Al sensitivity due to mis-localization. These results indicate that OsALS1 localized at the tonoplast is responsible for sequestration of Al into the vacuoles, which is required for internal detoxification of Al in rice.