霍山石斛PMM基因的克隆及其表达分析

Cloning and Quantitative Expression Analysis of PMM Gene from Dendrobium huoshanense

为研究磷酸甘露糖变位酶基因(PMM)的功能及其在多糖生物合成中的表达调控机制,以霍山石斛原球茎为材料,利用RT-PCR技术,克隆PMM基因,对其cDNA序列和表达情况进行分析。结果显示:霍山石斛PMM基因cDNA序列长949 bp,包含一个747 bp的开放阅读框,共编码248个氨基酸,GenBank中的登录号为KY912084。生物信息学分析表明:该蛋白属于HAD超家族,可能是一种稳定的、不具有信号肽和跨膜结构的亲水蛋白。系统进化树分析表明,霍山石斛PMM与铁皮石斛、海枣、油棕、芦笋亲缘关系较近,处于同一分支。qPCR结果显示:PMM基因在茎中的相对表达量最高;在4种不同药用石斛比较中,鼓槌石斛的相对表达量最高,霍山石斛的表达量最低。本研究结果表明PMM基因可能不仅参与到石斛多糖的合成,还与其它化合物的生物合成相关。

In the stusy, the cDNA sequence of PMM gene was isolated from the protocorm by RT-PCR, and its expression level was analyzed to elucidate the function of phosphomannomutase gene and its role during polysaccharides biosynthesis. The results showed that the length of PMM gene（ accession number was KY912084 in GenBank） was 949 bp, containing a 747 bp open reading frame encoding 248 amino acids. Bioinformatics analysis showed that the protein belonged to HAD superfamily and might be a kind of hydrophily and stable protein, which had no signal peptide and transmembrane structures. The phylogenetic tree analysis showed that the protein had closer relationship with Dendrobium catenatum, Phoenix dactylifera, Elaeis guineensis and Asparagus officinalis, which at the same branch. qPCR results indicated that PMM gene was highly expressed in the stem and the relative expression of PMM gene was the highest in Dendrobium chrysotoxum and the lowest in Dendrobium huoshanense in the comparison of the four different medicinal dendrobium. The results suggested that PMM gene may not only be involved in the synthesis of dendrobius polysaccharide, but also related to the biosynthesis of other compounds.