Component of the NF-Y/HAP transcription factor complex (By similarity). The NF-Y complex stimulates the transcription of various genes by recognizing and binding to a CCAAT motif in promoters (By similarity). Heterotrimeric transcription factor composed of three components, NF-YA, NF-YB and NF-YC (By similarity). NF-YB and NF-YC must interact and dimerize for NF-YA association and DNA binding (By similarity). Binds directly with DPB3-1 (PubMed:25490919). Expressed in flowers and green siliques. Repressed by heat and dehydration stress. Belongs to the NFYB/HAP3 subunit family.