Identification and characterization of CONSTANS-like genes from Curcuma alismatifolia

The CONSTANS ( CO ) and CONSTANS - like ( COL ) genes have an important role in the regulation of flowering in photoperiod-sensitive plants. However, information on the molecular characterization of COL genes in Curcuma alismatifolia is very limited. The objective of this study was to identify and evaluate 8 COL homologs ( CaCOLs ) in the C. alismatifolia transcriptome. Their structures, phylogenetic relationships and expressing patterns under short-day (SD) and long-day (LD) contexts were investigated. Our results showed that CaCOLs were classified into three groups: CaCOL3 and CaCOL6 in group I were the most CO - like genes; CaCOL7 and CaCOL8 in group II contains only one B-box; CaCOL1 to 2 and CaCOL4 to 5 formed the group III. Phylogenetic analysis of the CaCOLs in Arabidopsis, Rice, Barley, Malaccensis and C. alismatifolia demonstrated that both the B-box and CCT domains were conserved in dicot and monocot plants, but different groups of COL genes evolved independently. Different patterns of mRNA accumulation in C. alismatifolia leaves in response to SD and LD treatments were observed. CaCOL1 , CaCOL2 , CaCOL4 and CaCOL7 showed significantly higher expressions in LD treatment than that of SD, indicating that they were potential flowering inducers, and are candidate genes for research in flowering regulation and circadian controlling in C. alismatifolia plants. Altogether, our study facilitates successful regulation of flowering in Curcuma species and provides insights for future molecular breeding programs.