A genetic link between cold responses and flowering time through FVE in Arabidopsis thaliana

Cold induces expression of a number of genes that encode proteins that enhance tolerance to freezing temperatures in plants 1 , 2 . A cis -acting element responsive to cold and drought, the C-repeat/dehydration-responsive element (C/DRE), was identified in the Arabidopsis thaliana stress-inducible genes RD29A 3 and COR15a 4 and found in other cold-inducible genes in various plants 1 , 5 . C/DRE-binding factor/DRE-binding protein (CBF/DREB) is an essential component of the cold-acclimation response 1 , 2 , but the signaling pathways and networks are mostly unknown. Here we used targeted genetic approach to isolate A. thaliana mutants with altered cold-responsive gene expression ( acg ) and identify ACG1 as a negative regulator of the CBF/DREB pathway. acg1 flowered late and had elevated expression of FLOWERING LOCUS C ( FLC ) 6 , a repressor of flowering encoding a MADS-box protein. We showed that acg1 is a null allele of the autonomous pathway gene FVE . FVE encodes a homolog of the mammalian retinoblastoma-associated protein, a component of a histone deacetylase (HDAC) complex involved in transcriptional repression 7 , 8 . We also showed that plants sense intermittent cold stress through FVE and delay flowering with increasing expression of FLC . Dual roles of FVE in regulating the flowering time and the cold response may have an evolutionary advantage for plants by increasing their survival rates.