Organic acids (OA) are released from roots in response to aluminum (Al), conferring an Al tolerance to plants that is regulated by OA transporters such as ALMT (Al‐activated malate transporter) and multi‐drug and toxic compound extrusion (MATE). We have previously reported that the expression level polymorphism (ELP) of AtALMT1 is strongly associated with variation in Al tolerance among natural accessions of Arabidopsis. However, although AtMATE is also expressed following Al exposure and contributes to Al tolerance, whether AtMATE contributes to the variation of Al tolerance and the molecular mechanisms of ELP remains unclear. Here, we dissected the natural variation in AtMATE expression level in response to Al at the root using diverse natural accessions of Arabidopsis. Phylogenetic analysis revealed that more than half of accessions belonging to the Central Asia (CA) population show markedly low AtMATE expression levels, while the majority of European populations show high expression levels. The accessions of the CA population with low AtMATE expression also show significantly weakened Al tolerance. A single‐population genome‐wide association study (GWAS) of AtMATE expression in the CA population identified a retrotransposon insertion in the AtMATE promoter region associated with low gene expression levels. This may affect the transcriptional regulation of AtMATE by disrupting the effect of a cis‐regulatory element located upstream of the insertion site, which includes AtSTOP1 (sensitive to proton rhizotoxicity 1) transcription factor‐binding sites revealed by chromatin immunoprecipitation‐qPCR analysis. Furthermore, the GWAS performed without the accessions expressing low levels of AtMATE, excluding the effect of AtMATE promoter polymorphism, identified several candidate genes potentially associated with AtMATE expression.

中文翻译：

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单群体 GWAS 发现，由启动子变异引起的 AtMATE 表达水平多态性与当地拟南芥群体的铝耐受性变异相关。


根部响应铝 (Al) 释放有机酸 (OA)，赋予植物铝耐受性，该耐受性受 ALMT（铝激活苹果酸转运蛋白）和多药物和有毒化合物挤出 (MATE) 等 OA 转运蛋白调节。我们之前报道过AtALMT1的表达水平多态性 (ELP) 与拟南芥天然种质的铝耐受性变化密切相关。然而，尽管AtMATE在铝暴露后也会表达并有助于铝耐受性，但AtMATE是否有助于铝耐受性的变化以及 ELP 的分子机制仍不清楚。在这里，我们使用不同的拟南芥天然种质剖析了AtMATE表达水平的自然变化，以响应根部的 Al。系统发育分析显示，超过一半属于中亚 (CA) 种群的种质显示出明显较低的AtMATE表达水平，而大多数欧洲种群则显示出较高的表达水平。具有低AtMATE表达的 CA 群体的种质也显示出显着减弱的 Al 耐受性。 CA 群体中AtMATE表达的单群体全基因组关联研究 (GWAS) 发现AtMATE启动子区域中的逆转录转座子插入与低基因表达水平相关。这可能通过破坏位于插入位点上游的顺式调节元件的作用来影响AtMATE的转录调节，其中包括染色质免疫沉淀-qPCR 分析显示的 AtSTOP1（对质子根毒性 1 敏感）转录因子结合位点。 此外，在没有表达低水平AtMATE的种质的情况下进行的 GWAS，排除了AtMATE启动子多态性的影响，鉴定了几个可能与AtMATE表达相关的候选基因。