Ecotopic over-expression of an FT-homologus gene of Gossypium hirsutum induces early flowering in Arabidopsis thaliana and Nicotiana tabacum
Xianzhong Huang* Rui Dong, Chao Gu, Chao Li, Feng Zhang, Baiming Cui

Key Laboratory of Agrobiotechnology, College of Life Science, Shihezi University, Shihezi, xinjiang, 832003, China.
Corresping Author: Tel: +86 (0)993 2058500; E-mail: xianzhongh@shzu.edu.cn.

Abstract
Cloning and function research of FT (flowering locus T)-like homologs in cotton haven’t been reported. In the present study, an FT-Like homolog was isolated from Gossypium hirsutum L. through RT-PCR and RACE, which was designated GhFTL1 gene. The entire coding region is 525 bp and encoded a polypeptide of 174 amino acids with 75% homology to AtFT and 84% to Hd3a, respectively. GhFTL1 protein contains two critical residues tyrosine (Tyr) and glutamine (Gln), which identified as diagnostic of true FT family proteins. Phylogenetic analysis and 3-dimensional structure indicated GhFTL1 gene belongs to FT-like homologs.
GhFTL1 gene showed constitutive expression in cotton. The expression of GhFTL1 was regulated by photoperiod, with the highest expression from the 10th to 12th hour of the light period and the lowest expression at dawn, which is similar to FT in Arabidopsis. Over-expression of GhFTL1 not only in Arabidopsis thaliana but also in Nicotiana tabacum using the CaMV 35S promoter resulted in significant accelerated flowering compared with wild-type plants. GhFTL1 played an important role in flowering regulation of plants. The function of further research on GhFTL1 is now underway.
Key words: Florigen; GhFTL1; FLOWERING LOCUST; Early flowering; Gossypium hirsutum