provides C-function in floral organ identity through transcriptional regulation of in .

Floral development is one of the model systems for investigating the mechanisms underlying organogenesis in plants. Floral organ identity is controlled by the well-known ABC model, which has been generalized to many flowering plants. Here, we report a previously uncharacterized MYB-like gene, (), involved in flower development in the model legume Loss-of-function of results in flowers with stamens and carpel transformed into extra whorls of petals and sepals. Compared with the loss-of-function mutant of the class C gene () in , the defects in floral organ identity are similar between and , but the floral indeterminacy is enhanced in the mutant. Knockout of in the mutants of the class A gene or the class B gene leads to an addition of a loss-of-C-function phenotype, reflecting a conventional relationship of with the canonical A and B genes. Furthermore, we demonstrate that activates in transcriptional levels in control of floral organ identity. These data shed light on the conserved and diverged molecular mechanisms that control flower development and morphology among plant species.