TOO MUCH LOVE, a Root Regulator Associated with the Long-Distance Control of Nodulation in Lotus japonicus
TOO MUCH LOVE, a Root Regulator Associated with the Long-Distance Control of Nodulation in Lotus japonicus
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DOI：
10.1094/mpmi-22-3-0259
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发表时间：
2009-03-01
影响因子：
3.5
通讯作者：
Kawaguchi, Masayoshi
中科院分区：
文献类型：
--
作者：
Magori, Shimpei;Oka-Kira, Erika;Kawaguchi, Masayoshi
豆科植物严格控制共生根瘤的发育和数量。在日本莲中，这种调节需要在茎中存在HAR1（一种clavata1样受体激酶），这表明茎与根之间可能存在远距离通信。为了更好地了解其分子基础，我们分离并鉴定了一种名为too much love （tml）的日本血吸虫（L. japonicus）高调控突变体。与野生型相比，tml突变体产生的根瘤更多，根瘤密度更大，覆盖范围更广。互接表明，tml多结是由根基因型决定的。双突变分析进一步证实，嫁接har1根茎对根瘤数没有明显的加性影响。这些观察结果表明，茎部因子HAR1和根部因子TML参与控制根瘤数控制的远程信号传导的同一遗传途径。我们还发现，TML对结瘤的抑制作用可能是局部的。因此，TML可能在HAR1的下游发挥作用，其基因产物TML可能作为未知移动信号分子从茎向根运输的受体或中介。
Legume plants tightly control the development and number of symbiotic root nodules. In Lotus japonicus, this regulation requires HAR1 (a CLAVATA1-like receptor kinase) in the shoots, suggesting that a long-distance communication between the shoots and the roots may exist. To better understand its molecular basis, we isolated and characterized a novel hypernodulating mutant of L. japonicus named too much love (tml). Compared with the wild type, tml mutants produced much more nodules which densely covered a wider range of the roots. Reciprocal grafting showed that tml hypernodulation is determined by the root genotype. Moreover, grafting a har1 shoot onto a tml rootstock did not exhibit any obvious additive effects on the nodule number, which was further supported by double mutational analysis. These observations indicate that a shoot factor HAR1 and a root factor TML participate in the same genetic pathway which governs the long-distance signaling of nodule number control. We also showed that the inhibitory effect of TML on nodulation is likely to be local. Therefore, TML may function downstream of HAR1 and the gene product TML might serve as a receptor or mediator of unknown mobile signal molecules that are transported from the shoots to the roots.