Abstract
Leguminous plants have a systemic negative feedback regulatory mechanism called 'autoregulation' of nodulation. The gene involving in autoregulation of nodulation: HAR1 encodes receptor-like kinase (RLK) and in a comparison of Arabidopsis RLKs, HAR1 showed the highest similarity with CLAVATA1 (CLV1). CLV1 forms a receptor complex with receptor like protein; CLV2, and negatively regulates the formation of the shoot and floral meristem via a cell-cell communication involving CLAVATA3 (CLV3) peptide. Based on CLAVATA model, there is a possibility that HAR1 forms the receptor complex with LjCLV2 and recognize LjCLV3 as its ligand in Lotus japonicus. We found CLV2-like sequence (LjCLV2) and CLV3-like sequence (LjCLV3) from the genome of Lotus japonicus, so we generated LjCLV2- and LjCLV3-RNAi lines. LjCLV2-RNAi lines showed the increase in the number of nodule, whereas LjCLV3-RNAi lines showed fasciated shoots. These results indicate LjCLV2 involves in autoregulation, and LjCLV3 involves in maintenance of shoot apical meristem.
