苦荞查尔酮合成酶基因CHS的结构及花期不同组织表达量分析

采用同源克隆、染色体步移和RT-PCR技术，首次克隆到苦荞查尔酮合酶基因（CHS）的全长DNA序列和cDNA开放阅读框（ORF)序列. 序列分析表明，苦荞CHS DNA序列（GU172165）全长1 632 bp，含1个445 bp的内含子；cDNA编码区（HM852753）全长1 188 bp，编码395个氨基酸，命名为FtCHS. 生物信息学分析表明，FtCHS和推导的氨基酸序列与其它植物CHS基因同源率在95%以上，含有CHS多基因家族的标签序列（GFGPG）、活性位点、底物结合口袋位点和环化反应口袋位点. 半定量RT-PCR分析苦荞花期FtCHS空间表达模型表明，其表达量未成熟种子＞叶＞茎＞花＞根＞成熟种子，与苦荞芦丁含量的分布基本一致，具有组织特异性.

Molecular Structure Characterization of Fagopyrum tataricum Chalcone Synthase and Its Tissue-specific Expression during Florescence

The full length DNA and cDNA sequence of chalcone synthase gene (CHS) from Fagopyrum tataricum was isolated by homology cloning, genomic-walking, and RT-PCR. The CHS gene of F. tataricum (GU172165) is 1 632 bp, including a 445 bp intron; the coding region of cDNA (HM852753) is 1 188 bp, and it encodes a protein with 395 amino acids designated as FtCHS. Sequence analysis revealed that both FtCHS′s nucleotide and deduced amino acid sequences were highly identical with those of other plants (over 95% in similarity). FtCHS possesses four CHS-specific conserved motifs: a CHS-family Tag sequence (GFGPG), an active site, a substrate-binding pocket, and a cyclization pocket. The semi-quantitative RT-PCR analysis showed that FtCHS gene was highly expressed in immature seed, followed by leaf, stem and flower in amount, while lower in root and mature seed. The expression pattern of FtCHS gene is consistent to the distribution of rutin content in those tissues of F. tataricum, which indicated FtCHS′s expression had the tissue-specific during florescence.