烟草绿原酸合成关键基因NtHQT1的克隆及表达分析

Cloning and Expression Analysis of Chlorogenic Acid Biosynthetic Gene Nt HQT1 from Nicotiana tabacum

绿原酸(Chlorogenic acid,CGA)是烟叶中含量最高的多酚类物质,羟基肉桂酰辅酶A奎尼羟基肉桂转移酶(Hydroxycinnamoyl-Co A quinate hydroxycinnamoyl transferase,HQT)是植物绿原酸合成代谢途径中的关键酶。为研究HQT基因在烟草绿原酸合成中的作用机制,通过同源克隆技术从烟草中克隆到一个新的HQT基因,命名为Nt HQT1。生物信息学和激素处理后基因表达模式分析结果表明:Nt HQT1 c DNA全长1 305 bp,编码435个氨基酸,Nt HQT1定位在细胞质中,属于疏水性蛋白,其二级结构主要是螺旋和无规则卷曲;茉莉酸甲酯(Methyl jasmonate,Me JA)、生长素(3-Indoleacetic acid,IAA)、独角金内酯类似物(GR24)、细胞分裂素(6-Benzylaminopurin,6-BA)和赤霉素(Gibberellic acid,GA)能明显上调Nt HQT1基因的表达,脱落酸(Abscisic acid,ABA)对基因表达没有明显作用,预示Nt HQT1基因在烟草生长发育和抗病等生物学过程中发挥重要作用。

Chlorogenic acid is hydroxycinnamoyl transferase the dominant polyphenol in leaf tobacco. Hydroxycinnamoyl-CoA quinate （HQT） is the key enzyme in the metabolic pathway of chlorogenic acid in plant. In order to study the function mechanism of HQT gene in the synthesis of chlorogenic acid in tobacco, a new HQT gene was cloned from Nicotiana tabacum by homologous cloning technology and named as NtHQT1. The results of bioinformatics analysis and expression pattern analysis of genes treated by different hormones showed that NtHQT1 eDNA was 1 305 bp in length and encoded 435 amino acids; it was a hydrophobic protein and located in cytoplasm, its secondary structure was mainly of helix and random coil. The expression of NtHQT1 gene was obviously up-regulated by methyl jasmonate （MeJA）, auxin （3-Indoleacetic acid, IAA）, strigolactone （GR24）, cytokinin （6-BA） and gibberellin acid （GA）, while not obviously affected by abscisic acid （ABA）. It suggested that NtHQT1 might play an important role in the course of growth, development and disease resistance of tobacco.