《植物生理学报》 2016, 52(4): 445-453
通信作者：张孝廉；E-mail: xiaolian_zhang@sina.cn
摘 要：
赖氨酸脱羧酶(lysine decarboxylase, LDC)是生物碱合成第一步所需的关键酶。为研究LDC基因在烟草中特性和功能, 本研究采用同源克隆和RT-PCR方法从栽培烟草‘K326’中克隆得到一个LDC基因, 命名为NtLDC1, GenBank登录号为KU507075。序列分析表明烟草NtLDC1基因ORF全长666 bp, 编码221个氨基酸的蛋白, 相对分子质量为24 264.9 Da, 等电点为5.43。不同植物中LDC蛋白较为保守, NtLDC1与番茄和马铃薯的LDC蛋白高度相似, 进化分析表明NtLDC1与番茄中LDC的亲缘关系最近。利用实时荧光定量PCR对NtLDC1基因进行组织表达分析, 结果显示NtLDC1基因在烟草根、茎、叶、花中均有表达, 在叶片中的表达水平最高。低温可以诱导NtLDC1基因的表达, 在低温处理8 h基因的表达量达到最高, 表明NtLDC1可能在烟草低温胁迫应答中发挥作用。关键词：烟草; 赖氨酸脱羧酶(LDC); 基因克隆; 表达分析
收稿：2016-01-13 修定：2016-03-30
资助：烟草行业重点实验室专项(110201403019和110201403018)和中国烟草总公司科技重点项目(110201302004)。
Corresponding author: ZHANG Xiao-Lian; E-mail: xiaolian_zhang@sina.cn
Abstract:
Lysine decarboxylase (LDC) is the key enzyme in the first step of alkaloid synthesis. In order to study the characteristics and fuction of LDC in tobacco, we cloned a LDC gene from Nicotiana tabacum ‘K326’ by RT-PCR technology, naming NtLDC1, GenBank accession number is KU507075. NtLDC1 gene has a 666-bp open reading frame (ORF), encoding 221 amino acids. The putative protein molecular weight was 24 264.9 Da and its theoretical isoelectric point was 5.43. Sequence alignment displayed that LDC protein from different plants were conserved and that NtLDC protein showed high similarity to tomato and potato LDC proteins. Evolution analysis result suggested that NtLDC1 has the nearest genetic relationship with tomato LDC. Real-time PCR result showed that the relative expression level of NtLDC1 gene in leaf is the highest. Low temperature can induce NtLDC1 gene expression, the expression level peak at 8 h after low temperature treatment, suggesting NtLDC1 gene may play a role in the tobacco response to low temperature.Key words: tobacco; lysine decarboxylase; gene clone; expression analysis
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