棉花GhFTL1基因的克隆及初步功能分析

Cloning and Primary Analysis of the Function of GhFTL1 Gene in Cotton(Gossypium hirsutum L.)

通过RT-PCR结合RACE技术,从新疆陆地棉品种新陆早33中克隆到一个FT类似基因,命名为GhFTL1基因(登录号:HM631972)。该基因ORF(Open Reading Frame)全长为525 bp,可编码174个氨基酸,与其它植物中克隆的FT同源蛋白高度相似,含有FT蛋白亚家族两个关键的氨基酸残基及保守氨基酸基序。该基因在根、茎、花、叶片、纤维和胚珠中均有表达,且在叶片和胚珠中的表达要稍高于其它组织。系统进化分析表明GhFTL1属于FT亚家族成员。在18个已经证明可以促进植物开花的FT同源基因中,GhFTL1同苹果的MdFT1的遗传距离最接近。在拟南芥中过量表达GhFTL1,T1转基因植株要比野生型明显提早开花。表明GhFTL1可能属于开花途径中的重要作用因子之一。

A FT-like homolog was isolated from Gossypium hirsutum L. CV. Xinluzao 33 through RT-PCR and RACE, which was named GhFTL1 gene （accession number： HM631972）. The 525-bp open reading flame encoded a putative protein of 174 amino acids with high similarity to FT proteins of different plants which contains two critical residues and conserved motif, both of which identified as diagnostic of true FT. GhFTL1 gene showed constitutive expression in root, stem, flower, leaf, fiber, and ovule. The levels of transcript in leaf and ovule were higher than that in other tissues. Phylogenetic analysis at the amino acid level confirmed that the isolated sequence is FT-like, and also showed that GhFTL1 had shorter genetic distance with MdFT1 compared with other 18 FT homologs confirmed to inducing early flowering from 13 different plants. Over-expression of GhFTL1 in Arabidopsis using the CaMV 35S promoter resulted in significant accelerated flowering compared with wild-type plants. Based on our results, we concluded that GhFTL1 was responsible for inducing flowering and may be one of important components for the flowering pathway in cotton.