《植物生理学报》 2013, 49(12): 1368-1374

苎麻小分子G蛋白Rac1基因的克隆及表达分析

黄丽华¹, 胡超¹, 陈建荣², 郭清泉², 张学文^1,*

¹湖南农业大学生物科学技术学院, 长沙410128; ²长沙学院生物工程与环境工程系, 长沙410003

通信作者：张学文；E-mail: xwzhang@hunau.edu.cn；Tel: 0731-84673602

摘　要：

植物Rac是植物中特有的小分子G蛋白, 我们从苎麻转录组中获得一个小分子G蛋白基因cDNA的部分序列, 设计引物后采用RT-PCR结合RACE技术克隆了该基因的cDNA。序列分析表明, 所克隆的Rac1 cDNA全长为1 043 bp, 包括594 bp开放阅读框、214 bp的3′端非编码区和235 bp的5′端非编码区, 能编码一个197氨基酸的推导蛋白。该蛋白包含G蛋白典型的效应因子结合位点、GTP/GDP结合位点和碱性氨基酸区, C末端具有保守的异戊烯基化位点CSIL。采用半定量RT-PCR分析了该基因在5个苎麻品种及不同组织器官中的表达情况, 结果表明Rac1基因在苎麻根、茎、叶中均有表达, 其中在叶中的表达量最高。纤维木质素含量不同的品种中, Rac1基因的表达量存在明显差异。木质素含量高的品种具有较高的Rac1基因表达, 表明该基因可能在苎麻木质素合成过程中发挥作用。

关键词：苎麻; Rac1基因; 克隆; 表达分析

收稿：2013-08-09   修定：2013-10-21

资助：国家自然科学基金(31071457)、湖南省研究生科研创新项目(11C0665)、湖南省科技计划项目(2012NK3062)和作物种质创新与资源利用重点实验室培育基地科学基金开放项目(12KFXM11)

Cloning and Expression Analysis of a Small G Protein Rac1 Gene cDNA from Boehmeria nivea (Linn.) Gaudich

HUANG Li-Hua¹, HU Chao¹, CHEN Jian-Rong², GUO Qing-Quan², ZHANG Xue-Wen^1,*

¹College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; ²Department of Bioengineering & Environmental Science, Changsha University, Changsha 410003, China

Corresponding author: ZHANG Xue-Wen; E-mail: xwzhang@hunau.edu.cn; Tel: 0731-84673602

Abstract:

Rac small G proteins of plants belong to a unique subfamily named ROP (Rho-related GTPase from plants). Here, a Rac protein gene was isolated from Boehmeria nivea by RT-PCR and RACE based on the sequence of Rac gene in B. nivea transcriptome. The cDNA was 1 043 bp, contained a 594 bp opening reading frame, a 3'-untranslated region of 214 bp, 5'-untranslated region of 235 bp and encoded a putative protein of 197 amino acids with molecular weight 21.65 kDa and isoelectric point 9.30. BnRac1 contains four conserved domains for guanine nucleotide binding and GTPase activities, an effector domain, a polybasic region and a C-terminal motif for prenylation. Semi-quantitative RT-PCR analysis revealed that the transcript level of BnRac1 was higher in leaves than those in other issues. Moreover, BnRac1 gene showed the high transcript abundance in a variety with high lignin content in fiber. It turned out that BnRac1 gene was likely involved in lignin biosynthesis in B. nivea.

Key words: Boehmeria nivea; Rac1 gene; cloning; expression analysis