《植物生理学报》 2016, 52(6): 895-904

油桐VfFATB1基因的克隆及其功能的初步分析

刘美兰, 龙洪旭, 谭晓风^*

中南林业科技大学, 经济林培育与保护省部共建教育部重点实验室, 长沙410004

通信作者：谭晓风；E-mail: tanxiaofengcn@126.com

摘　要：

以油桐转录组数据中FATB1基因的cDNA片段为模板, 通过RACE技术克隆获得该基因的CDS, 命名为VfFATB1, 并进行了生物信息学分析, 同时通过Real-time PCR和亚细胞定位对该基因的表达模式和表达部位进行了研究分析。结果表明VfFATB1是一个由8个α-螺旋和10个β-折叠组成“hot-dog”折叠结构的二聚体, 与JcFATB1相似度高达92%; 该基因有FAT重要催化作用的半胱氨酸活性位点Cys320和3个保守的组氨酸位点His140/285/345; 该基因在油脂合成后期种仁中的表达量最高, 是幼根的30倍左右, 且在油脂合成过程中一直是上调状态; 该基因定位于叶绿体中。综上所述, VfFATB1是一个位于叶绿体中且含有多个催化功能结构的蛋白, 表达模式与油脂积累相同, 因此它可能与油脂合成有着密切的关系, 这为油桐的遗传改良提供了潜在的基因资源。

关键词：油桐; 脂肪酸生物合成; FATB1; 生物信息学; 表达模式; 亚细胞定位

收稿：2016-03-09   修定：2016-05-13

资助：国家林业公益性行业科研专项重点项目(201204403)。

Cloning and preliminary functional analysis of VfFATB1 in tung tree

LIU Mei-Lan, LONG Hong-Xu, TAN Xiao-Feng^*

Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees, Ministry of Education, Central South University of Forestry and Technology, Changsha 410004, China

Corresponding author: TAN Xiao-Feng; E-mail: tanxiaofengcn@126.com

Abstract:

In this research, we report the cloning and functional analysis of VfFATB1 in tung tree (Vernicia fordii) that shares high similarity with Jatropha curcas to FATB1 (fatty acyl-ACP thioesterase B1) gene, up to 92%. The encoded protein contains a typical domain of “hot dog” folds composed 8 α-helixes and 10 β-sheets. It also has one essential Cys320 residue and three conserved His140/285/345 of FAT catalytic sites. At the same time, it has highest expression in the seed kernel, about 30 times than radicle, and was significantly increased during fatty acid synthesis of tung seed. Furthermore, VfFATB1 is located in the chloroplast. Taken together, VfFATB1 has many functional catalytic sites and locates in the chloroplast which implys that VfFATB1 has a close relationship with fatty acid synthesis.

Key words: tung tree (Vernicia fordii); fatty acid biosynthesis; FATB1; bioinformatics; expression patterns; subcellular localization