LEUNIG_HOMOLOG transcriptional co-repressor mediates aluminium sensitivity through PECTIN METHYLESTERASE46-modulated root cell wall pectin methylesterification in Arabidopsis
LEUNIG_HOMOLOG transcriptional co-repressor mediates aluminium sensitivity through PECTIN METHYLESTERASE46-modulated root cell wall pectin methylesterification in Arabidopsis
复制标题
LEUNIG_HOMOLOG 转录共阻遏物通过果胶甲基酯酶 46 调节拟南芥根细胞壁果胶甲基酯化介导铝敏感性
DOI：
10.1111/tpj.13506
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发表时间：
2017-05-01
期刊：
影响因子：
7.2
通讯作者：
Yang, Zhong-Bao
中科院分区：
文献类型：
--
作者：
Geng, Xiaoyu;Horst, Walter J.;Yang, Zhong-Bao
高等植物中决定铝（Al）敏感性的一个主要因素是铝与根细胞壁的结合。细胞壁的铝结合能力与果胶甲基酯化程度密切相关，因为连接在果胶主链上的甲基基团的存在会降低这种聚合物的净负电荷，从而限制铝的结合。尽管最近在理解多种植物的铝抗性分子基础方面取得了进展，但对于果胶的甲基化状态如何响应铝胁迫进行调节还不太清楚。在此我们在拟南芥中表明，缺乏基因LEUNIG_HOMOLOG（LUH）的突变体（LUH是Groucho样转录共抑制因子家族的成员）对铝介导的根生长抑制不太敏感。这种表型与luh根细胞壁中甲基化果胶水平的增加以及细胞壁相关基因表达的改变相关。在受LUH抑制的基因中，果胶甲基酯酶46（PME46）被确定为可减少铝与细胞壁的结合，从而通过降低PME酶活性缓解铝诱导的根生长抑制。seuss - like2（slk2）突变体对铝的反应与luh突变体相似，这表明LUH - SLK2复合物抑制PME46的表达。这些数据被整合到一个模型中，该模型提出PME46是根细胞壁内果胶甲基酯酶活性的主要抑制因子。
A major factor determining aluminium (Al) sensitivity in higher plants is the binding of Al to root cell walls. The Al binding capacity of cell walls is closely linked to the extent of pectin methylesterification, as the presence of methyl groups attached to the pectin backbone reduces the net negative charge of this polymer and hence limits Al binding. Despite recent progress in understanding the molecular basis of Al resistance in a wide range of plants, it is not well understood how the methylation status of pectin is mediated in response to Al stress. Here we show in Arabidopsis that mutants lacking the gene LEUNIG_HOMOLOG (LUH), a member of the Groucho-like family of transcriptional co-repressor, are less sensitive to Al-mediated repression of root growth. This phenotype is correlated with increased levels of methylated pectin in the cell walls of luh roots as well as altered expression of cell wall-related genes. Among the LUH-repressed genes, PECTIN METHYLESTERASE46 (PME46) was identified as reducing Al binding to cell walls and hence alleviating Al-induced root growth inhibition by decreasing PME enzyme activity. seuss-like2 (slk2) mutants responded to Al in a similar way as luh mutants suggesting that a LUH-SLK2 complex represses the expression of PME46. The data are integrated into a model in which it is proposed that PME46 is a major inhibitor of pectin methylesterase activity within root cell walls.