<i>CmARF3</i>–<i>CmTCP7</i> module regulates flowering time in chrysanthemum (<i>Chrysanthemum morifolium</i>)

The precise timing of flowering in response to environment plays a crucial role in the reproductive processes of plants. The FLOWERING LOCUS T (FT)-FD module is a well-established key node in the photoperiod-mediated pathway. However, the identity of novel partners involved in this network and its regulatory mechanisms remain elusive in most nonmodel species. Here, we found that <i>TEOSINTE BRANCHED1</i>/<i>CYCLOIDEA</i>/<i>PROLIFERATING CELL FACTOR7</i> (<i>CmTCP7</i>) functions as a floral repressor in <i>Chrysanthemum morifolium</i>. Its upstream transcriptional regulator <i>AUXIN RESPONSE FACTOR3</i> (<i>CmARF3</i>) promotes flowering by directly repressing <i>CmTCP7</i> expression. The expression levels of both genes are short-day inducible. Interestingly, FLOWERING LOCUS T-like3 (CmFTL3) interacts with FD-like1 (CmFDL1), which activates flowering<i>-</i>accelerating gene <i>Chrysanthemum Dendrathema MADS111</i>-<i>like</i> (<i>CmCDM111L</i>). Meanwhile, CmTCP7 interacts with CmFTL3 and CmFDL1, delaying the CmFTL3 and CmFDL1 complex-promoted flowering in chrysanthemum "Jinba." These findings reveal a novel regulatory module controlling photoperiod-dependent flowering in chrysanthemum.