An ERF transcription factor in Medicago truncatula that is essential for nod factor signal transduction
An ERF transcription factor in Medicago truncatula that is essential for nod factor signal transduction
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DOI：
10.1105/tpc.106.048264
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发表时间：
2007-04-01
期刊：
影响因子：
11.6
通讯作者：
Oldroyd, Giles E. D.
中科院分区：
文献类型：
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作者：
Middleton, Patrick H.;Jakab, Julia;Oldroyd, Giles E. D.
根瘤菌在适当的寄主豆科植物上激活根瘤的形成，这需要细菌信号分子Nod因子。植物中的结瘤因子的感知导致许多根瘤菌诱导的基因的激活。已知GRAS家族中的推定转录调节因子在结瘤因子信号传导中起作用，但这些蛋白质尚未显示出能够直接DNA结合。在这里，我们确定了一个ERF转录因子，ERF所需的结（ERN），其中包含一个高度保守的AP2 DNA结合域，这是必要的结。该基因的突变阻断了根瘤菌侵入结构（称为感染丝）的启动和发展，从而阻断了细菌对根瘤的侵入。我们表明，ERN是必要的结瘤因子诱导的基因表达和自发性激活的钙和钙调蛋白依赖性蛋白激酶，DMI3，这是一个组件的结瘤因子信号通路。我们认为ERN是结瘤因子信号转导通路的一个组成部分，在DMI3的下游起激活结瘤基因表达的作用。
Rhizobial bacteria activate the formation of nodules on the appropriate host legume plant, and this requires the bacterial signaling molecule Nod factor. Perception of Nod factor in the plant leads to the activation of a number of rhizobial-induced genes. Putative transcriptional regulators in the GRAS family are known to function in Nod factor signaling, but these proteins have not been shown to be capable of direct DNA binding. Here, we identify an ERF transcription factor, ERF Required for Nodulation (ERN), which contains a highly conserved AP2 DNA binding domain, that is necessary for nodulation. Mutations in this gene block the initiation and development of rhizobial invasion structures, termed infection threads, and thus block nodule invasion by the bacteria. We show that ERN is necessary for Nod factor - induced gene expression and for spontaneous nodulation activated by the calcium- and calmodulin-dependent protein kinase, DMI3, which is a component of the Nod factor signaling pathway. We propose that ERN is a component of the Nod factor signal transduction pathway and functions downstream of DMI3 to activate nodulation gene expression.