The timing of floral induction is tightly controlled by environmental cues and intrinsic signals. The critical role of gibberellin (GA) in this process has been extensively studied in the past decades. DELLA proteins serve as the central regulatory hubs of GA signaling. The mechanism of GA-dependent transcription involves the recruitment of DELLA proteins to transcription factors. In general, epigenetic modifiers are believed to cooperate with transcription factors to regulate gene expression, but how epigenetic regulation participates in GA-dependent transcription of the floral integrator genes in plants remains unclear.

Dr. Chunyu Zhang and Mingyang Jian from South China Botanical Garden of Chinese Academy of Sciences have reported A molecular module in gibberellin signaling-mediated flowering. BRAHMA (BRM), a core catalytic subunit of the SWI/SNF-type chromatin remodeling complex, is involved in GA signaling-mediated flowering via the formation of the DELLA-BRM-NF-YC module in Arabidopsis. DELLA proteins promote the interaction of BRM with the transcription factor NUCLEAR FACTOR Y-C (NF-YC), impairing the binding of NF-YC to the floral integrator gene SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1), resulting in late flowering. Meanwhile, DELLA proteins accelerate the binding of BRM to SOC1. In the presence of GA, GA-triggered DELLA degradation disturbs the DELLA-BRM-NF-YC module and the H3K4me3 level at SOC1 chromatin increases, resulting in higher gene expression and early flowering.

The study has been published in the online edition of the international journal The Plant Cell. This work was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Guangdong Province. For further reading, please refer to: https://www.webofscience.com/wos/alldb/full-record/MEDLINE:37294919

Figure. A proposed model illustrating how the DELLA-BRM-NF-YC module regulates GA signaling-mediated flowering.