23株不同地理来源嗜酸硫杆菌的系统发育及其遗传差异

Phylogenetic and genetic heterogeneity of 23 Acidithiobacillus strains isolated from different geographical locations

摘要:

[目的]研究不同地理来源嗜酸硫杆菌的系统发育及其遗传差异，以及基因指纹图谱技术聚类与嗜酸硫杆菌地理来源的相关性。[方法]采用16S-23S rRNA间隔区（ITS）序列建立系统发育树，并结合ERIC和BOXAIR两种引物进行rep-PCR，以及rus基因扩增，对不同地理来源嗜酸硫杆菌进行分析。[结果]分离自不同样点的23株嗜酸硫杆菌遗传差异显著，依据ITS序列系统发育树被划分为5个大类群，与rep-PCR指纹图谱的分类结果较为接近，其中Acidithiobacillus ferrooxidans在ITS系统发育和BOXAIR-PCR指纹聚类分析中被划分为2个类群，但在ERIC-PCR中归为1个类群，rus基因分组中，在系统发育和聚类分析中处于同一类群的菌株拥有不同类型的rus基因，说明嗜酸硫杆菌的亚铁氧化途径与系统发育类群无明显相关性；ITS基因拥有区分近缘种或亚种的能力，且BOXAIR-PCR的分辨能力较强，非常适于嗜酸硫杆菌的遗传差异分析。

Abstract:

[Objective] To study the phylogenetic and genetic heterogeneity of 23 Acidithiobacillus strains from various geographical locations, as well as the relationship between the DNA fingerprinting classification and geographical origin of Acidithiobacillus. [Methods] Partial 16S-23S rRNA gene intergenic spacer (ITS) was used to construct corresponding phylogenetic trees based on the sequence homology. rus gene amplification and rep-PCR assay with two different primers (BOXAIR and ERIC) were performed to analyze genetic heterogeneity of Acidithiobacillus strains from diverse environment. [Results] Acidithiobacillus revealed a great genetic heterogeneity. The whole isolates were classified into five groups by ITS sequence analysis. This result was similar with that obtained by rep-PCR. Acidithiobacillus ferrooxidans strains were always divided into two groups of phylogenetic and BOXAIR fingerprinting cluster analysis. However, these were clustered one group in the ERIC dendrogram. Genotypic analysis of the rus gene suggested that different iron oxidation pathways have been evolved in these closely related bacteria. Taken together, the iron oxidation pathway of Acidithiobacillus and phylogenetic groups have no obvious correlation. ITS gene has been proven very useful in distinguishing closely related species or subspecies of Acidithiobacillus, to BOXAIR-PCR, which has been recommended as reliable tool for genetic heterogeneity analysis of Acidithiobacillus.