Soybean Nodule-Enhanced CLE Peptides in Roots Act as Signals in GmNARK-Mediated Nodulation Suppression
Soybean Nodule-Enhanced CLE Peptides in Roots Act as Signals in GmNARK-Mediated Nodulation Suppression
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DOI：
10.1093/pcp/pcr091
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发表时间：
2011-09-01
影响因子：
4.9
通讯作者：
Hwang, Cheol Ho
中科院分区：
文献类型：
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作者：
Lim, Chae Woo;Lee, Young Woo;Hwang, Cheol Ho
豆科植物根中形成的根瘤的数量是由根瘤自动调节（AON）系统控制的。本研究的特点是两个CLAVATA 3/胚乳周围区域（CLE）基因参与AON信号转导。GmRIC 1和GmRIC 2基因在接种后约3天（DAI）仅在根中开始表达，对应于AON的时间点，并且表达被细胞分裂素上调。GmRIC 1和GmRIC 2基因的表达水平高得多，在超结突变体，SS 2 -2，比野生型（WT）大豆在根瘤发育过程中，甚至在固氮开始后。在3 DAI，GmRIC 2被诱导的细胞的周皮层和外皮层，进行细胞分裂，形成结节原基和蔓延从中央区域到整个结节，因为它的发展。GmRIC 1和GmRIC 2的过表达以GmNARK依赖的方式强烈抑制WT根以及转基因毛状根的形成。这种系统性的抑制是由两种CLE蛋白分泌到细胞外空间引起的。WT和SS 2 -2大豆之间的双嫁接表明，在开花期间，SS 2 -2根中的信号Q大于WT根中的信号Q。本研究结果表明，GmRIC 1和GmRIC 2是AON信号转导中根源信号Q的良好候选者。
The number of nodules formed in the roots of leguminous plants is systemically controlled by autoregulation of nodulation (AON). This study characterized two of the CLAVATA3/endosperm-surrounding region (CLE) genes involved in AON signal transduction. The GmRIC1 and GmRIC2 genes initiated expression solely in the roots at approximately 3 days after inoculation (DAI) with Nod factor-producing rhizobia, corresponding to the time point of AON, and the expression was up-regulated by cytokinins. Levels of GmRIC1 and GmRIC2 gene expression were much higher in the supernodulation mutant, SS2-2, than in wild-type (WT) soybeans during nodule development, even after initiation of nitrogen fixation. At 3 DAI, GmRIC2 was induced in the cells of the pericycle and the outer cortex, which undergo cell division to form nodule primordia and spreads from the central region to the whole nodule as it develops. Overexpression of GmRIC1 and GmRIC2 strongly suppressed the nodulation of WT roots as well as transgenic hairy roots in a GmNARK-dependent manner. This systemic suppression of nodulation was caused by the secretion of two CLE proteins into the extracellular space. Double grafting between WT and SS2-2 soybeans showed that signal Q is larger in SS2-2 than in WT roots during nodulation. The results of this study suggest that GmRIC1 and GmRIC2 are good candidates for root-derived signal Q in AON signal transduction.