Modification of cell wall properties has been considered as one of the determinants that confer aluminum (Al) tolerance in plants, while how cell wall modifying processes are regulated remains elusive. Here, we present a WRKY transcription factor WRKY47 involved in Al tolerance and root growth. Lack of WRKY47 significantly reduces, while overexpression of it increases Al tolerance. We show that lack of WRKY47 substantially affects subcellular Al distribution in the root, with Al content decreased in apoplast and increased in symplast, which is attributed to the reduced cell wall Al‐binding capacity conferred by the decreased content of hemicellulose I in the wrky47‐1 mutant. Based on microarray, real time‐quantitative polymerase chain reaction and chromatin immunoprecipitation assays, we further show that WRKY47 directly regulates the expression of EXTENSIN‐LIKE PROTEIN (ELP) and XYLOGLUCAN ENDOTRANSGLUCOSYLASE‐HYDROLASES17 (XTH17) responsible for cell wall modification. Increasing the expression of ELP and XTH17 rescued Al tolerance as well as root growth in wrky47‐1 mutant. In summary, our results demonstrate that WRKY47 is required for root growth under both normal and Al stress conditions via direct regulation of cell wall modification genes, and that the balance of Al distribution between root apoplast and symplast conferred by WRKY47 is important for Al tolerance.

中文翻译：

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WRKY转录因子通过调节细胞壁修饰基因赋予铝耐受性。

细胞壁特性的改变已被认为是赋予植物铝（Al）耐受性的决定因素之一，而如何调节细胞壁修饰过程仍然遥遥无期。在这里，我们介绍了一个WRKY转录因子WRKY47，它参与了铝的耐性和根的生长。缺乏WRKY47会大大减少，而过表达WRKY47则会增加铝的耐受性。我们发现WRKY47的缺乏会严重影响根中亚细胞的Al分布，质外体中Al含量降低，共生质中Al含量增加，这归因于Wrkky47-中半纤维素I含量降低导致细胞壁Al结合能力降低。1个突变体。基于微阵列，实时定量聚合酶链反应和染色质免疫沉淀测定法，我们进一步表明WRKY47直接调节负责细胞壁修饰的EXTENSIN-LIKE蛋白质（ELP）和XYLOGLUCAN内源性葡糖苷酶-HYDROLASES17（XTH17）的表达。增加的表达ELP和XTH17救出Al耐受以及根的生长在wrky47-1突变体。总之，我们的结果表明，通过直接调节细胞壁修饰基因，在正常和Al胁迫条件下，根系生长都需要WRKY47，并且WRKY47赋予根质外质和共生质之间的Al分布平衡对于Al的耐受性很重要。