海岛棉GbMFT1基因的克隆及表达分析

Cloning and Expression Analysis of GbMFT1 Gene in Gossypium barbadense L.

通过RT-PCR和RACE技术,从新疆海岛棉品种新海14中克隆得到了一个MFT(MOTHER OF FT AND TFL1)类似基因,命名为GbMFT1基因(GenBank登录号为KC513744)。GbMFT1基因的开放阅读框(ORF)为528 bp,编码175个氨基酸的蛋白,含一个磷脂酰乙醇胺结合蛋白(PEBP)结构域。GbMFT1蛋白的羧基端含有MFT蛋白都含有的脯氨酸。系统进化树分析表明GbMFT1编码产物与葡萄、番茄亲缘关系较近,属于同一进化分支。实时荧光定量PCR分析表明,GbMFT1基因在棉花的不同组织中均有表达,在花瓣中的表达量较高;在纤维发育的不同时期中均有表达,在开花后2 d的胚珠、9 d的纤维中表达量最高。半定量RT-PCR结果表明,GbMFT1基因在刚萌发的种子中表达量高,用不同浓度的ABA处理种子后其表达变化不明显,表明GbMFT1基因的表达不受ABA的调节。

Angiosperm genes sharing a conserved phosphatidylethanolamine-binding（PEBP） domain have been shown to be involved in the control of flowering time.The family is divided into three subfamilies,FT-like,TFL1-like and MFT-like.Evolution analysis showed that MOTHER OF FT AND TFL1（MFT） is the ancestral form of all PEBP genes in plant;however the exact fuction of MFT is still unknown.One MFT-like homolog,designated GbMFT1,was isolated from Gossypium barbadense L.cv.Xinhai 14 using RT-PCR and RACE methods.The open reading frame of GbMFT1 is 528 bp in length,which encodes a putative protein of 175 amino acids.GbMFT1 gene has a PEBP conserved motif.In consistency with almost all MFT-like proteins,GbMFT1 has a conserved proline residue near the C-terminus.Phylogenetic analysis revealed that GbMFT1 has high sequence similarities with VvMFT and SP2G and they belong to the same clade.The result of qRT-PCR assay indicated that GbMFT1 expressed in different tissues of cotton,with a maximum expression in petal,and in different developmental stages of fibre,especially in two-day ovule and nine-day fibre.Semiquantitative RT-PCR assay indicated that GbMFT1 had a high level of transcription at the beginning of seed germination.Exogenous abscisic acid（ABA） of different concentrations resulted in no significant change in GbMFT1 expression in germinating seeds,indicating that the expression of this gene is not regulated by ABA.