-like genes of promote flowering targeting different loci in a concentration-dependent manner.

genes are famous for their function in the morphological novelty of bisexual flowers. Although the diverse functions of genes were reported, only the regulatory mechanisms underlying floral organ development have been addressed. In this study, we identified -like genes in and found that genes were duplicated in diploid cotton varieties. and were abundantly transcribed in the shoot apical meristem (SAM), but only was expressed in the leaf vasculature. The expression pattern of s in floral organs was conserved with that of homologs in , except for that was preponderantly expressed in ovules and fibers. The overexpression and silencing of each single gene suggested their distinct role in promoting flowering direct binding to and genomic regions. The curly leaf and floral defects in overexpression lines with a higher expression of genes revealed the concentration-dependent target gene regulation of GhSEP proteins. Moreover, GhSEP proteins were able to dimerize and interact with flowering time regulators. Together, our results suggest the dominant role of in leaves to promote flowering , and differently accumulated GhSEP proteins in the SAM alternately participate in forming the dynamic tetramer complexes to target at the different loci of and to maintain reproductive growth. The regulatory roles of cotton genes reveal their conserved and diversified functions.