The ERN1 transcription factor gene is a target of the CCaMK/CYCLOPS complex and controls rhizobial infection in Lotus japonicus
The ERN1 transcription factor gene is a target of the CCaMK/CYCLOPS complex and controls rhizobial infection in Lotus japonicus
复制标题
ERN1转录因子基因是CCaMK/CYCLOPS复合体的靶标，控制着百脉根的根瘤菌感染
DOI：
10.1111/nph.14547
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发表时间：
2017-07-01
期刊：
影响因子：
9.4
通讯作者：
Parniske, Martin
中科院分区：
文献类型：
--
作者：
Cerri, Marion R.;Wang, Quanhui;Parniske, Martin
细菌在植物活细胞内的适应仅限于固氮根瘤共生。在许多豆科植物中，细菌的吸收是通过被称为感染丝（ITs）的管状结构介导的。为了鉴定成功共生感染所需的植物基因，我们筛选了一个甲基磺酸乙酯诱变的百脉根（Lotus acetylum）群体，寻找IT形成缺陷的突变体，并克隆了编码AP 2/ERF转录因子的相关基因ERN 1。我们进行了两个独立的L. lactobacillus突变体等位基因的表型分析，并通过反式激活和DNA-蛋白质相互作用检测ERN 1的调节。在ERN 1突变体根中，根瘤原基形成，但大多数仍然未被感染，细菌通过ITs进入根表皮被取消。受感染的皮质结节细胞含有类杆菌，但很少观察到跨细胞的IT。一个子集表现出局部的细胞壁降解和细胞完整性的损失与类杆菌传播到邻近的cells和the apoplast.Functional启动子的研究表明，CYCLOPS结合在一个序列特异性的方式内的ERN 1启动子和结合CCaMK积极调节ERN 1转录的基序。我们的结论是ERN 1的激活CCaMK/CYCLOPS复合物是一个重要的步骤，控制IT介导的细菌进入植物细胞。
Bacterial accommodation inside living plant cells is restricted to the nitrogen-fixing root nodule symbiosis. In many legumes, bacterial uptake is mediated via tubular structures called infection threads (ITs).To identify plant genes required for successful symbiotic infection, we screened an ethyl methanesulfonate mutagenized population of Lotus japonicus for mutants defective in IT formation and cloned the responsible gene, ERN1, encoding an AP2/ERF transcription factor. We performed phenotypic analysis of two independent L.japonicus mutant alleles and investigated the regulation of ERN1 via transactivation and DNA-protein interaction assays.In ern1 mutant roots, nodule primordia formed, but most remained uninfected and bacterial entry via ITs into the root epidermis was abolished. Infected cortical nodule cells contained bacteroids, but transcellular ITs were rarely observed. A subset exhibited localized cell wall degradation and loss of cell integrity associated with bacteroid spread into neighbouring cells and the apoplast.Functional promoter studies revealed that CYCLOPS binds in a sequence-specific manner to a motif within the ERN1 promoter and in combination with CCaMK positively regulates ERN1 transcription. We conclude that the activation of ERN1 by CCaMK/CYCLOPS complex is an important step controlling IT-mediated bacterial progression into plant cells.