The Mediator complex subunits MED25/PFT1 and MED8 are required for transcriptional responses to changes in cell wall arabinose composition and glucose treatment in Arabidopsis thaliana.
The Mediator complex subunits MED25/PFT1 and MED8 are required for transcriptional responses to changes in cell wall arabinose composition and glucose treatment in Arabidopsis thaliana.
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DOI：
10.1186/s12870-015-0592-4
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发表时间：
2015-09-05
影响因子：
5.3
通讯作者：
Bevan MW
中科院分区：
文献类型：
--
作者：
Seguela-Arnaud M;Smith C;Uribe MC;May S;Fischl H;McKenzie N;Bevan MW
植物细胞壁是动态结构，涉及植物生长、环境相互作用和防御反应的各个方面，并且是地球上含碳聚合物最丰富的可再生来源。为了平衡刚性和延展性，细胞壁成分的组成和完整性需要受到严格调控，例如在细胞伸长过程中。
我们发现中介体转录复合物的MED25/PFT1和MED8亚基的突变抑制了hsr8 - 1突变体对糖超敏感的下胚轴伸长表型，该突变体由于阿拉伯糖缺乏而具有细胞壁缺陷，无法正常进行细胞伸长。这种抑制作用独立于光和茉莉酸（JA）信号传导。基因表达分析表明，在hsr8 - 1中诱导表达的、编码参与细胞扩张和细胞壁强化的酶和蛋白质的基因在pft1 - 2突变株系中的表达降低，而编码参与减少下胚轴细胞伸长的转录因子的基因、编码细胞壁相关酶和蛋白质的基因在pft1 - 2中表达上调。PFT1也是几个葡萄糖诱导基因表达所必需的，这些基因包括编码细胞壁成分和酶、花青素生物合成的调节和酶促成分以及类黄酮和硫代葡萄糖苷生物合成途径的基因。
这些结果表明，中介体转录复合物的MED25和MED8亚基对于响应细胞壁缺陷的参与细胞伸长和细胞壁组成的基因的转录调控以及糖响应基因表达是必需的。
本文的在线版本（doi:10.1186/s12870 - 2015 - 0592 - 4）包含补充材料，可供授权用户使用。
Plant cell walls are dynamic structures involved in all aspects of plant growth, environmental interactions and defense responses, and are the most abundant renewable source of carbon-containing polymers on the planet. To balance rigidity and extensibility, the composition and integrity of cell wall components need to be tightly regulated, for example during cell elongation. We show that mutations in the MED25/PFT1 and MED8 subunits of the Mediator transcription complex suppressed the sugar-hypersensitive hypocotyl elongation phenotype of the hsr8-1 mutant, which has cell wall defects due to arabinose deficiency that do not permit normal cell elongation. This suppression occurred independently of light and jasmonic acid (JA) signaling. Gene expression analyses revealed that the expression of genes induced in hsr8-1 that encode enzymes and proteins that are involved in cell expansion and cell wall strengthening is reduced in the pft1-2 mutant line, and the expression of genes encoding transcription factors involved in reducing hypocotyl cell elongation, genes encoding cell wall associated enzymes and proteins is up-regulated in pft1-2. PFT1 was also required for the expression of several glucose-induced genes, including those encoding cell wall components and enzymes, regulatory and enzymatic components of anthocyanin biosynthesis, and flavonoid and glucosinolate biosynthetic pathways. These results establish that MED25 and MED8 subunits of the Mediator transcriptional complex are required for the transcriptional regulation of genes involved in cell elongation and cell wall composition in response to defective cell walls and in sugar- responsive gene expression. The online version of this article (doi:10.1186/s12870-015-0592-4) contains supplementary material, which is available to authorized users.