摘要
查尔酮合成酶是银杏叶黄酮合成途径中的第一个关键酶。利用RACE技术克隆到银杏的一个查尔酮合成酶基因,命名为GbCHS2,其cDNA全长1608bp,包括长1173bp的读码框,编码391个氨基酸。GbCHS2蛋白与已从银杏克隆到的GbCHS1蛋白具有很高的同源性,并包含其所有相同的活性位点。用半定量RT-PCR方法研究了银杏叶生长过程中chs基因的转录水平的变化,并对CHS活性变化和黄酮含量的变化曲线进行了线性回归分析。结果显示,在整个银杏叶生长过程中,CHS活性与黄酮含量呈极显著线性相关,表明CHS是银杏叶黄酮合成途径中的一个关键限速酶;chs基因的转录水平的变化与黄酮的积累是同步的,chs基因的这种表达模式表明chs基因的转录水平可能决定了银杏叶黄酮的积累。
Chalcone synthase （CHS） catalyses the first and key regulatory step of flavonoid biosynthetic pathway. A chalcone synthase gene was isolated from Ginkgo biloba leaves using the method of rapid amplification of the cDNA ends （RACE）. The full-length cDNA, designated as GbCHS2, is 1 608 bp in length （GenBank accession No. DQ054841） and contains an open reading frame of 1 173 bp encoding a protein of 391 amino acids. Alignment of the predicted amino acid sequence of GbCHS2 has been shown to have high sequence similarity with GbCHS1. All the active sites and active site motifs in GbCHS1 protein were also found in GbCHS2. Correlation analysis between CHS activity and flavonoid accumulation during ginkgo leaf growth indicated that CHS might be the rate-limiting enzyme in the biosynthesis pathway of flavonoids in ginkgo leaves. Results of semi-quantitative RT-PCR analysis showed that flavonoid accumulation paralleled the transcription level of change in chs gene, suggesting chs gene as the specific key gene regulating flavonoid accumulation in ginkgo leaves.
出处
《植物生理与分子生物学学报》
CAS
CSCD
北大核心
2007年第4期309-317,共9页
Journal Of Plant Physiology and Molecular Biology
基金
教育部新世纪优秀人才支持计划(No.NCET-04-0746)
教育部地方重大攻关项目(教育部地方02095)
湖北省自然科学基金(No.2002AB094)
湖北省青年杰出人才基金(No.2003AB014)
湖北省教育厅重大项目(No.Z200627002)资助~~
关键词
银杏
查尔酮合成酶基因
表达
时间进程
黄酮
Ginkgo biloba
chalcone synthase gene
expressiontime course
flavonoid
