梨萜类合成酶基因家族生物信息学与表达模式分析

Genome-wide Identification and Expression Analysis of TPS Gene Family in Pear

萜类合成酶(Terpene synthases,TPS)是萜类化合物合成过程中的关键酶。基于梨(Pyrus bretschneideri)全基因组数据库,采用生物信息学和分子生物学方法,对梨TPS基因家族进行鉴定和亚家族分类,研究梨TPS基因的结构及编码蛋白质性质和表达模式。共鉴定获得33个萜类合成酶基因家族成员,聚类为5个亚家族,其中,TPS-a亚家族成员数量最多,包含4-7个外显子;主要定位于细胞质,少数分布在线粒体、叶绿体和内质网等;梨TPS蛋白均为亲水性蛋白,α-螺旋和无规卷曲是其二级结构主要组成元件,β-折叠和延伸链散布其中;TPS-a中保守基序个数相对较多,TPS-e/f相对较少;各亚族内蛋白质在三级结构上高度相似。除PbrTPS24外,其余9个TPS基因在根、茎、幼叶和幼芽中均有表达,并且不同的基因在不同部位高表达,PbrTPS存在组织特异性表达。

Terpene synthases（TPS）are the key enzymes in the synthesis of terpenoids. The TPS gene family was identified and subfamilies were clustered based on the genome-wide database of Pyrus bretschneideri,then the structure of TPS genes,the characteristics ofencoded proteins and expression patterns were analyzed by means of bioinformatics and molecular biology. The results showed that 33 TPS genefamily members were identified and they were clustered into five subfamilies. Among them,TPS-a subfamily had the largest number of membersand owned 4-7 exons;most of TPS proteins were located in cytoplasm,and a few of them were distributed in mitochondria,chloroplasts andendoplasmic reticulum. All pear TPS proteins were hydrophilic proteins,the secondary structure of most TPS proteins was α-helix and randomcoil,and the folded and extended strands scattered in it. TPS-a subfamily had the largest number of conserved motifs and less in TPS-e/f.Proteins in each subfamily were highly similar in tertiary structure. The qRT-PCR analysis of 10 TPS genes showed that 9 PbrTPS genes exceptPbrTPS24 expressed in roots,stems,young leaves and sprouts,each gene expressed highly in different part,indicating that the expression of PbrTPS gene was tissue-specific.