Identification of ZmNF-YC2 and its regulatory network for maize flowering time.Flowering time is an important agronomic trait that determines the distribution and adaptation of plants.  Here we cloned the flowering time-controlling gene, ZmNF-YC2, by map-based cloning and confirmed that ZmNF-YC2 is the nuclear transcription factor Y subunit C-2 protein and a positive regulator of flowering time in maize under long-day conditions.  Our results show that ZmNF-YC2 promotes the expression of ZmNF-YA3.  We then developed a gene regulatory model of flowering time in maize using ZmNF-YC2, ZmNF-YA3, ZmAP2, ZMM4, and other key genes.  The cascading regulation by ZmNF-YC2 of maize flowering time has not been reported in other species.
ZmNF-YC2
Our results show that ZmNF-YC2 promotes the expression of ZmNF-YA3.  ZmNF-YA3 negatively regulates the transcription of ZmAP2.  We then developed a gene regulatory model of flowering time in maize using ZmNF-YC2, ZmNF-YA3, ZmAP2, ZMM4, and other key genes. 
ZmNF-YA3
ZmNF-YA3 negatively regulates the transcription of ZmAP2.  ZmAP2 suppresses the expression of ZMM4 to delay flowering time.  We then developed a gene regulatory model of flowering time in maize using ZmNF-YC2, ZmNF-YA3, ZmAP2, ZMM4, and other key genes. 
ZmAP2
ZmAP2 suppresses the expression of ZMM4 to delay flowering time.  We then developed a gene regulatory model of flowering time in maize using ZmNF-YC2, ZmNF-YA3, ZmAP2, ZMM4, and other key genes. 
ZMM4