MtHAP2-1 is a key transcriptional regulator of symbiotic nodule development regulated by microRNA169 in Medicago truncatula

A new transcription factor of the CCAAT-binding family, MtHAP2-1, is identified in the model legume Medicago truncatula, for which RNA interference (RNAi) and in situ hybridization experiments have indicated a key role during nodule development. The complementary expression pattern of miR169 and MtHAP2-1 and the phenotype of miR-resistant MtHAP2-1 nodules have suggested that the miR169-mediated restriction of MtHAP2-1 expression to the nodule meristematic zone is necessary for the differentiation of nodule cells.