以23S rDNA一个多变区作为分子标记对致病杆菌属细菌进行分类鉴定

Variable fragment of 23S rDNA for classification and identification of Xenorhabdus

摘要:

摘要:【目的】致病杆菌属(Xenorhabdus) 细菌是一类重要的生物杀虫剂，斯氏属昆虫病原线虫的共生菌，建立快速准确的分类鉴定方法，对研究开发这类细菌至关重要。【方法】本研究PCR 扩增测序了本室保藏的26株，含20种已定名致病杆菌属细菌的一段845 bp 的23S rDNA 序列，构建了基于这段序列的致病杆菌属系统树并与基于几乎全长16S rDNA 序列的相应系统树进行比较，分析了两者作为致病杆菌属细菌分类鉴定分子标记的优缺点。【结果】结果表明，与全长16S rDNA 序列相比，所选择的23S rDNA 序列片段所含可变位点、简约信息位点比例更高，遗传距离数值跨度大。【结论】上述结果显示该序列片段可用于致病杆菌属细菌进行分类鉴定，特别适用于对野外资源调查中采集到的大量菌株进行快速鉴定。

关键词:关键词: 23S rDNA，16S rDNA，致病杆菌属，分类鉴定

Abstract:

Abstract:［Objective］Members of Xenorhabdus are symbiotic bacteria of entomopathogenic nematodes Steinernema，and can be applied as biopesticides against insects． Therefore，a rapid and accurate method for classification and identification of Xenorhabdus is essential． ［Methods］ An 845bp-fragment of 23S rDNA sequence of 26 strains of Xenorhabdus representing 20 described species was PCR amplified and sequenced． A phylogenetic tree of Xenorhabdus based on the sequences obtained was constructed and compared to that based on nearly complete 16S rDNA sequences for suitability as molecular maker for classification and identification of Xenorhabdus． ［Results］ The 23S rDNA fragment contained more variable and parsimony-informative sites proportionally，and with greater pairwise distances among sequences compared to those of 16S rDNA．［Conclusion］ The 23S rDNA fragment can be used to identify Xenorhabdus，especially for a large number of Xenorhabdus strains obtained from field survey．

Key words:Keywords: 23S rDNA，16S rDNA，Xenorhabdus，classification and identification