《植物生理学报》 2016, 52(1): 92-100

落叶松生长素受体基因LkTIR1的克隆及功能分析

李爱, 于雪, 冯涛, 李慧, 于玮玮, 彭立新^*

天津农学院园艺园林学院, 天津300384

通信作者：彭立新；E-mail: lovelee@mail.nankai.edu.cn

摘　要：

以本实验室前期建立的落叶松(Larix kaempferi)转录组数据库为基础, 利用RT-PCR从落叶松中克隆获得一个1 725 bp的生长素受体基因全长编码序列, 命名为LkTIR1。蛋白结构特性分析发现LkTIR1编码574个氨基酸, 蛋白分子质量为64 397 Da, 等电点为6.97, 为亲水性蛋白。蛋白二级结构主要包括α-螺旋、β-折叠和环肽链。功能结构域分析显示该蛋白包含6个富含亮氨酸重复基序和1个F-box蛋白结构域, 推测其属于F-box基因家族。多重序列比对和系统进化分析表明LkTIR1所编码的氨基酸与裸子植物火炬松(Pinus taeda)亲缘关系最近。同时, 通过构建植物表达载体, 利用浸花法转化模式植物拟南芥的功能研究发现, 过量表达落叶松LkTIR1的转基因拟南芥叶片显著变大, 叶片数目明显增多, 这表明落叶松生长素受体基因LkTIR1在植物的生长发育过程中起着重要的调节作用。

关键词：落叶松; 生长素受体; LkTIR1; 拟南芥

收稿：2015-10-30   修定：2015-12-28

资助：国家自然科学基金青年项目(31300564)和天津市应用基础与前沿技术研究计划(14JCQNJC15000、14JCYBJC30100和15JCQNJC15100)。

Cloning and functional characterization of auxin receptor gene LkTIR1 in Larix kaempferi

LI Ai, YU Xue, FENG Tao, LI Hui, YU Wei-Wei, PENG Li-Xin^*

College of Horticulture Landscape, Tianjin Agricultural University, Tianjin 300384, China

Corresponding author: PENG Li-Xin; E-mail: lovelee@mail.nankai.edu.cn

Abstract:

Based on the Larix kaempferi transcriptome database previously established in our laboratory, the cDNA sequence of an auxin receptor gene named LkTIR1 was obtained by using RT-PCR technique. The length of LkTIR1 open reading frame (ORF) was 1 725 bp, encoding 574 amino acid residues. The molecular weight and theoretic isoelectric point of LkTIR1 protein were 64 397 Da and 6.97, respectively. The secondary structure of LkTIR1 contained α-helixes, β-sheets and loops. The LkTIR1 was predicted to contain six leucine-rich-repeat (LRR) domains and one F-box domain, implying it is belonged to F-box gene family. In addition, LkTIR1 protein had the highest sequence similarity (about 90%) and the closest genetic relationship to Pinus taeda. To elucidate the function of LkTIR1, 35S::LkTIR1 overexpression vector was constructed and transformed to Arabidopsis via dip flower. Compared with the empty vector control lines, the LkTIR1 overexpressed transgenic plants had remarkably enlarged leaves, and significantly increased leaf numbers, suggesting a key role of LkTIR1 in plant growth and development regulation.

Key words: Larix kaempferi; auxin receptor; LkTIR1; Arabidopsis