CmbHLH110, a novel bHLH transcription factor, accelerates flowering in chrysanthemum

Basic helix–loop–helix (bHLH) transcription factor gene family in plants controls various growth and development aspects; however, the actual roles of these genes in flowering plants are not well known. In this study, a novel bHLH protein CmbHLH110 was found to interact with CmERF110 by and experiments, a chrysanthemum ERF110 homolog that acts as a positive flowering regulator. In addition, was also found to regulate the flowering of chrysanthemums, overexpression of causes chrysanthemums to flower earlier, and suppressed leads to delayed flowering. Furthermore, the loss-of-function mutant of its homologue () had a noticeable late flowering phenotype, and completely complemented the late flowering phenotype of the mutant, whereas heterologous overexpression of in Col-0 caused early flowering. Transcriptome sequencing revealed significant differential expression of flowering-related and circadian clock-related genes in transgenic chrysanthemum. Therefore, we concluded that CmbHLH110, as a novel flowering regulator, could interact with CmERF110 to regulate flowering in chrysanthemum.