The B-box protein CmBBX8 recruits chromatin modifiers CmFDM2/CmSWI3B to induce flowering in summer chrysanthemum.

The transition from vegetative to reproductive growth is essential for the flowering process of plants. In summer chrysanthemum, CmBBX8 exploits prominence function in floral transition by activating the expression of CmFTL1. However, how CmBBX8 induces CmFTL1 during the photoperiod inductive cycles remains unknown.

The Cm14-3-3μ protein and CCT transcription factor CmNRRa delay flowering in chrysanthemum.

The floral transition from vegetative to reproductive growth is pivotal in the plant life cycle. NUTRITION RESPONSE AND ROOT GROWTH (OsNRRa), as a CONSTANS, CONSTANS-LIKE, TOC1 (CCT) domain protein, delays flowering in rice, and an orthologous protein, CmNRRa, inhibits flowering in chrysanthemum; however, the underlying mechanism remains unknown. In this study, using yeast two-hybrid screening, we identified the 14-3-3 protein family member Cm14-3-3µ as a CmNRRa-interacting protein.

CmRCD1 represses flowering by directly interacting with CmBBX8 in summer chrysanthemum.

The CmBBX8-CmFTL1 regulatory module is a key determinant in the transition from vegetative growth to reproductive development in summer-flowering chrysanthemum. However, the detailed regulatory mechanism of CmBBX8-mediated flowering remains elusive. In this study, we revealed that RADICAL-INDUCED CELL DEATH 1 (CmRCD1) physically associated with CmBBX8 through bimolecular fluorescence complementation (BiFC), pulldown and Coimmunoprecipitation (CoIP) assays.