CmARF3–CmTCP7 module regulates flowering time in chrysanthemum (Chrysanthemum morifolium)

Abstract 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 TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR7 (CmTCP7) functions as a floral repressor in Chrysanthemum morifolium. Its upstream transcriptional regulator AUXIN RESPONSE FACTOR3 (CmARF3) promotes flowering by directly repressing CmTCP7 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-accelerating gene Chrysanthemum Dendrathema MADS111-like (CmCDM111L). 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.