Mechanisms and regulation of aluminum-induced secretion of organic acid anions from plant roots
Mechanisms and regulation of aluminum-induced secretion of organic acid anions from plant roots
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DOI：
10.1631/jzus.b1900188
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发表时间：
2019-05
影响因子：
5.1
通讯作者：
Jian-li Yang;W. Fan;S. Zheng
中科院分区：
文献类型：
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作者：
Jian-li Yang;W. Fan;S. Zheng
铝（Al）是地壳中含量最丰富的金属元素。在酸性土壤上，当pH值低于5.5时，部分不溶性含铝矿物溶解于土壤溶液中，对植物的生长和发育产生高度毒性作用。然而，一些植物已经开发出铝耐受机制，使他们能够抵消这种铝毒性。一个这样的有据可查的机制是铝诱导的有机酸阴离子的分泌，包括柠檬酸，苹果酸和草酸，从植物根。一旦分泌，这些阴离子螯合外部铝离子，从而保护分泌植物免受铝毒害。编码柠檬酸和苹果酸转运蛋白的基因已被鉴定和表征，越来越多的证据表明，这些转运蛋白基因的表达调控是植物耐铝的关键。本文综述了近年来植物耐铝机制的研究进展，重点介绍了铝诱导植物根系分泌有机酸阴离子的生理机制。特别是，我们总结了识别基因编码的有机酸转运蛋白和审查目前了解的基因调节有机酸分泌。我们还讨论了调节有机酸转运蛋白基因表达的可能信号通路。
Aluminum (Al) is the most abundant metal element in the earth’s crust. On acid soils, at pH 5.5 or lower, part of insoluble Al-containing minerals become solubilized into soil solution, with resultant highly toxic effects on plant growth and development. Nevertheless, some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity. One such well-documented mechanism is the Al-induced secretion of organic acid anions, including citrate, malate, and oxalate, from plant roots. Once secreted, these anions chelate external Al ions, thus protecting the secreting plant from Al toxicity. Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized, and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance. In this review, we outline the recent history of research into plant Al-tolerance mechanisms, with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots. In particular, we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion. We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.