Host: The Japanese Society of Plant Physiologists
Pages 0176
Legumes possess systemic feedback mechanism to control the nodulation. HAR1, which was identified from Lotus japonicus as a shoot factor of this mechanism, encodes a receptor-like kinase (RLK). Among all Arabidopsis RLKs, HAR1 showed the highest similarity with CLAVATA1 (CLV1). CLV1 is estimated to recognize CLV3 peptide. This raises the possibility that HAR1 interact with CLV3-like (CLE) peptide. So, we identified 32 putative LjCLE sequences from Lotus genome. Expression analysis showed three LjCLE genes were significantly upregulated in the root by rhizobial infection. Among them, over-expressed LjCLE1 and LjCLE2 in hairy root system inhibited nodulation strongly. This suppression was cancelled in har1 mutant. Further analysis showed that LjCLE1 and LjCLE2 are upregulated immediately after rhizobium inoculation. Furthermore, Nod Factor (NF) and some components of NF signaling pathway are required for the induction of LjCLE1 and LjCLE2. These results suggest that LjCLE1 and LjCLE2 function in systemic regulation of nodulation.
