Flowering, the predominant reproductive strategy in the plant life cycle, is an intricate process regulated by both genetic and environmental factors. In Gossypium hirsutum , flowering time significantly influences adaptation and yield. Here, we identify the transcription factor GhCIL1 (GhCIB1-Like) as a pivotal regulator promoting flowering in this crucial crop. Overexpression of GhCIL1 presented significantly shorter bolting and flowering time in Arabidopsis thaliana , while the silencing of GhCIL1 in cotton has been shown to delay bud appearance and flowering. Through the joint analysis of transcriptome based on the OE- GhCIL1 and CR- GhCIL1 , it was found that GhCIL1 may regulate GhSWEET15-D04 , GhSWEET15-A04 and GhPRR5 . Electrophoretic mobility shift assays (EMSAs) and Dual-luciferase assays demonstrated that GhCIL1 could directly bind to and promote the expression of GhSWEET15-D04 , GhSWEET15-A04 , GhPRR5 , and GhFT . The GhCIL1 possesses the capacity to form homodimers independently or heterodimers in conjunction with GhPRE6. silencing of GhPRE6 in cotton has been shown to promote bud appearance and flowering. Dual-luciferase assays and EMSAs demonstrated that the cotransformation of GhCIL1 and GhPRE6 inhibited the promotion and binding effect of GhCIL1 on GhSWEET15-D04 , GhSWEET15-A04 , GhPRR5 , and GhFT . In conclusion, our work unveils a novel the flowering regulation pathway in cotton. Figure Molecular model of the involvement of GhCIL1 and GhPRE6 in the regulation of flowering.The bHLH transcription factors GhCIL1 promotes the expression of GhSWEET15-D04 , GhSWEET15-A04 and GhPRR5 and GhFT , thereby promoting flowering. However, its interaction partner, GhPRE6, can inhibition this activation, leading to the inhibition of flowering. • GhCIL1 expression regulates flowering in upland Gossypium hirsutum. • GhCIL1 may regulate GhSWEET15-D04 , GhSWEET15-A04 , GhFT and GhPRR5. • GhCIL1 possesses the capacity to form homodimers independently. • GhCIL1can form heterodimers in conjunction with GhPRE6. • 5.GhPRE6 inhibits the regulation of downstream genes by GhCIL1.
Sun et al. (Sun,) studied this question.