NENA, a Lotus japonicus Homolog of Sec13, Is Required for Rhizodermal Infection by Arbuscular Mycorrhiza Fungi and Rhizobia but Dispensable for Cortical Endosymbiotic Development
NENA, a Lotus japonicus Homolog of Sec13, Is Required for Rhizodermal Infection by Arbuscular Mycorrhiza Fungi and Rhizobia but Dispensable for Cortical Endosymbiotic Development
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DOI：
10.1105/tpc.109.069807
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发表时间：
2010-07-01
期刊：
影响因子：
11.6
通讯作者：
Parniske, Martin
中科院分区：
文献类型：
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作者：
Groth, Martin;Takeda, Naoya;Parniske, Martin
豆科植物与丛枝菌根（AM）真菌和固氮根瘤细菌形成共生。细胞内根感染的内共生体是由激活的钙和钙调素依赖性激酶（CCaMK），植物的共同共生信号网络的中央调节组件控制。我们进行了一个显微镜屏幕百脉根突变体AM发展缺陷，并分离出一个突变体，nena，流产真菌感染的根皮层。NENA编码与核孔蛋白Sec13和Seh 1相关的WD 40重复蛋白。定位NENA的核边缘和酵母双杂交实验表明，NENA在一个保守的核孔支架亚复合物的作用。虽然nena突变体能够形成粉红色的根瘤共生中根瘤菌loti，根毛感染没有观察到。此外，NIN，SbtM4和SbtS的共生基因的结瘤因子诱导，以及核周钙尖峰，受损。nena突变体的详细表型分析揭示了根瘤菌感染模式，克服了缺乏根皮反应，并进行裂纹进入的标志，包括对乙烯的要求。CCaMK依赖的过程被取消，但在皮层的nena突变体的根皮。这些数据支持组织特异性成分激活CCaMK的概念。
Legumes form symbioses with arbuscular mycorrhiza (AM) fungi and nitrogen fixing root nodule bacteria. Intracellular root infection by either endosymbiont is controlled by the activation of the calcium and calmodulin-dependent kinase (CCaMK), a central regulatory component of the plant's common symbiosis signaling network. We performed a microscopy screen for Lotus japonicus mutants defective in AM development and isolated a mutant, nena, that aborted fungal infection in the rhizodermis. NENA encodes a WD40 repeat protein related to the nucleoporins Sec13 and Seh1. Localization of NENA to the nuclear rim and yeast two-hybrid experiments indicated a role for NENA in a conserved subcomplex of the nuclear pore scaffold. Although nena mutants were able to form pink nodules in symbiosis with Mesorhizobium loti, root hair infection was not observed. Moreover, Nod factor induction of the symbiotic genes NIN, SbtM4, and SbtS, as well as perinuclear calcium spiking, were impaired. Detailed phenotypic analyses of nena mutants revealed a rhizobial infection mode that overcame the lack of rhizodermal responsiveness and carried the hallmarks of crack entry, including a requirement for ethylene. CCaMK-dependent processes were only abolished in the rhizodermis but not in the cortex of nena mutants. These data support the concept of tissue-specific components for the activation of CCaMK.