Deregulation of a Ca2+/calmodulin-dependent kinase leads to spontaneous nodule development
Deregulation of a Ca2+/calmodulin-dependent kinase leads to spontaneous nodule development
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DOI：
10.1038/nature04862
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发表时间：
2006-06-28
期刊：
影响因子：
64.8
通讯作者：
Stougaard, Jens
中科院分区：
文献类型：
--
作者：
Tirichine, Leila;Imaizumi-Anraku, Haruko;Stougaard, Jens
根瘤菌诱导植物新器官的发育是豆科植物根瘤与固氮菌共生的最显著表现。在这里，我们表明，复杂的根瘤有机程序可以遗传失调，引发从头根瘤形成根瘤菌或外源信号的情况下。在乙基甲烷磺酸盐诱导的snf 1（自发结节形成）突变体的莲花，一个单一的氨基酸置换的钙/钙调蛋白依赖性蛋白激酶（CCaMK）是足以把完全分化的根皮层细胞分生组织的创始人细胞的根瘤原基。这些自发的根瘤是真正的根瘤，其个体发育与根瘤菌诱导的根瘤相似，证实了以前的生理研究（1）。使用两个受体缺陷的遗传背景，我们提供了证据，发育整合的自发性acidulation过程是独立的脂几丁质-寡糖信号感知和振荡的Ca 2+第二信使水平。我们的研究结果揭示了细胞周期激活所需的所有组件的CCaMK上游的一个关键的监管位置，和一系列的突变等位基因表现出积极和消极的调节过程。
Induced development of a new plant organ in response to rhizobia is the most prominent manifestation of legume root-nodule symbiosis with nitrogen-fixing bacteria. Here we show that the complex root-nodule organogenic programme can be genetically deregulated to trigger de novo nodule formation in the absence of rhizobia or exogenous rhizobial signals. In an ethylmethane sulphonate-induced snf1 (spontaneous nodule formation) mutant of Lotus japonicus, a single amino-acid replacement in a Ca2+/calmodulin-dependent protein kinase (CCaMK) is sufficient to turn fully differentiated root cortical cells into meristematic founder cells of root nodule primordia. These spontaneous nodules are genuine nodules with an ontogeny similar to that of rhizobial-induced root nodules, corroborating previous physiological studies(1). Using two receptor-deficient genetic backgrounds we provide evidence for a developmentally integrated spontaneous nodulation process that is independent of lipochitin-oligosaccharide signal perception and oscillations in Ca2+ second messenger levels. Our results reveal a key regulatory position of CCaMK upstream of all components required for cell-cycle activation, and a phenotypically divergent series of mutant alleles demonstrates positive and negative regulation of the process.