紫花苜蓿γ-生育酚甲基转移酶(γ-TMT)基因的克隆与逆境下的表达分析  

Cloning the gene of γ-tocopherol methyltransferase(γ-TMT) from alfalfa and expression analysis in adverse situations

作　　者：贾会丽[1] 王学敏[2] 高洪文[2] 董洁[2] 王运琦[1] 刘建宁[1] 石永红[1] 

机构地区：[1]山西省农业科学院畜牧兽医研究所,山西太原030032 [2]中国农业科学院北京畜牧兽医研究所,北京100193

出　　处：《草业学报》2012年第6期198-206,共9页Acta Prataculturae Sinica

基　　金：现代农业产业技术体系建设专项牧草产业体系;农业部俄罗斯牧草种质资源保护项目;山西省农业科学院畜牧兽医研究所(XMS1105)资助

摘　　要：紫花苜蓿是目前全国乃至世界上种植最多的牧草,在畜牧业生产中发挥着重要的作用。γ-生育酚甲基转移酶(γ-TMT)是维生素E合成途径中一种重要的合成酶,催化γ-生育酚向α-生育酚的转化,改变维生素E组成,利于动物和人体的吸收。本实验通过RACE-PCR技术,得到紫花苜蓿γ-TMT基因的全长cDNA序列,命名为MsT-MT。测序和生物信息学分析表明,此序列全长1 306bp,包含1个长为939bp的完整开放阅读框(ORF),编码312个氨基酸。MsTMT属于甲基转移酶家族(AdoMet-MTases),有1个腺苷脱氨基酶信号(SLSTDDP),包含有2个保守的S-腺苷甲硫氨酸结合结构域(XXDXGCGIG,VXXPGGXXIX)。Real-time PCR检测结果表明MsTMT基因在紫花苜蓿各组织中均有表达,叶片中表达量最高。受NaCl、PEG以及黑暗诱导后,该基因表达上调;低温胁迫后该基因表达下降;外源ABA不影响该基因的表达。Alfalfa plays an important role in livestock production and is the most widely cultivated forage plant in China.γ-tocopherol methyltransferase（γ-TMT） is an important enzyme in the vitamin E synthetic pathway.γ-TMT catalyzes the conversion from γ-tocopherol to α-tocopherol which changes the vitamin E composition so that it can be easily absorbed by humans and animals.The full-length cDNA of alfalfa γ-TMT was cloned by RACE-PCR and termed MsTMT.Bioinformatic analysis showed that the full-length cDNA of this gene was 1 306 bp,including a 939 bp open reading frame（ORF）,which encoded a polypeptid of 312 amino acids.MsTMT belongs to the AdoMet-MTases,which possess an adenosine deaminase signal（SLSTDDP） and two conserved SAM-domains（XXDXGCGIG,VXXPGGXXIX）.Real-time PCR results revealed that the MsTMT gene is expressed in all organs of alfalfa,but especially in the leaves.The expression level of MsTMT in leaves increased with NaCl,PEG and dark stress,but decreased with cooling stress.Exogenous ABA did not affect the gene expression.

关 键 词：紫花苜蓿 Γ-生育酚甲基转移酶 维生素E 抗逆性 

分 类 号：S541.9[农业科学—作物学]