摘要： 以种不同来源的梨基因组DNA为模板，根据已经发表的多酚氧化酶基因序列设计引物，利用PCR技术，克隆到了鸭梨、雪花梨、砂梨、黄冠梨约1.8 kb的完整多酚氧化酶基因，将纯化后的扩增产物克隆到质粒pGEM－T vector中，转化DH－5α菌，挑选阳性克隆进行测序。利用Clustalx软件对PPO核苷酸序列进行了同源性分析，用DNAStar软件对PPO核苷酸序列进行进化树分析，并进行部分植物PPO氨基酸的同源性分析。结果表明，种梨多酚氧化酶基因的蛋白编码区含有1 782个核苷酸，鸭梨基因已经在GenBank上登录，登录号为EU08225.梨多酚氧化酶基因与其他植物中的多酚氧化酶基因有较高的相似性，尤其在铜离子结合部位，所有的植物基本上一致；5种梨的同源性高达98%。基于植物PPO基因核苷酸序列的分子进化树显示，可分为两大类，梨的多酚氧化酶可以与大多数的木本植物聚合成一个组。

关键词: 梨, PPO基因, 克隆, 序列比较

Abstract: PCRs were performed on genomic DNAs of four pear cultivars Sand pear,Huangguan pear,Xueli pear,Yali pear using primers derived from sequences of previous published PPO.The target bands were recovered and purified.The fragments were ligated with the plasmid of p GEM-T Vector by the method of direct TA cloning.The mixtures of ligation were transformed into DH-5α and the positive clones were screened and sequenced.Phylogenetic tree analysis of the plantPPOgene sequences were made by the software of Clustalx and DNAStar.The results showed these enzymes coding region each containing 1 782 oligodeoxynucleotides and the obtainedPPOgene of Yali pear was registered in Genbank,whose accession number is EU048225.The five types pear shared high sequence homology of 98 %.ThePPOgenes were divided into two groups based on phylogenetic tree analysis of the plantPPOgene sequences.ThePPOgenes of the pears can be clustered in the same group with most other woody plants according to phylogenetic tree analysis.

Key words: Pear, Polyphenol oxidase gene, Cloning, Sequence comparison

中图分类号: 

• Q785