Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, NY, USA.
Plant Signal Behav. 2010 Apr;5(4):403-5. doi: 10.4161/psb.5.4.10801. Epub 2010 Apr 29.
Legume plants tightly control the number and development of root nodules. This is partly regulated by a long-distance signaling known as auto-regulation of nodulation (AON). AON signaling involves at least two potential long-distance signals: root-derived signal and shoot-derived signal. However, their molecular characteristics and the mode of action remain unclear. In our recent study, we isolated a novel Lotus japonicus hypernodulating mutant too much love (tml). Based on several grafting experiments, we concluded that its causative gene TML functions as a receptor of the shoot-derived signal. This finding prompted us to ask how the candidates of the long-distance signal molecules, LjCLE-RS1/2 and jasmonic acid (JA), are affected in tml mutants. Expression analysis revealed that rapid induction of LjCLE-RS1/2 upon rhizobial inoculation is still intact in tml, supporting that TML plays a role in reception of the shoot-derived signal but not in generation of the root-derived signal. Furthermore, physiological analysis showed that JA, a candidate of the shoot-derived signal, can suppress tml hypernodulation. Therefore, contrary to the previous report, JA might not be a component of AON signaling.
豆科植物严格控制根瘤的数量和发育。这部分受一种称为结瘤自动调控（AON）的长距离信号调控。AON 信号涉及至少两种潜在的长距离信号：根衍生信号和茎衍生信号。然而，它们的分子特征和作用模式仍不清楚。在我们最近的研究中，我们分离了一个新型的多根瘤的 Lotus japonicus 突变体 too much love（tml）。基于几个嫁接实验，我们得出结论，其致病基因 TML 作为茎衍生信号的受体发挥作用。这一发现促使我们提出这样的问题：候选的长距离信号分子 LjCLE-RS1/2 和茉莉酸（JA）在 tml 突变体中是如何受到影响的。表达分析表明，在根瘤菌接种时 LjCLE-RS1/2 的快速诱导在 tml 中仍然完整，这支持 TML 在茎衍生信号的接收中发挥作用，但不在根衍生信号的产生中发挥作用。此外，生理分析表明，JA，一种茎衍生信号的候选物，可以抑制 tml 的过度结瘤。因此，与之前的报告相反，JA 可能不是 AON 信号的组成部分。
