Random amplified polymorphic DNA analysis of Acidithiobacillus caldus strains recovered from different extreme environments

A total of twenty-one Acidithiobacillus caldus strains were isolated from fourteen samples of acidic hydrothermal spring and acid mine drainage, collected at several geographically insulated sites in China. To elucidate phylogenetic relationships among the twenty-one newly isolated strains of A. caldus and the strain variability correlated with geographic insulation and environmental variation, genomic DNA was extracted from the isolates and a standard strain of A. caldus and PCR for each template DNA was carried out using fourteen 10-mer primers. A RAPD (Random Amplification Polymorphic DNA) profile of 264 distinctive banding patterns was obtained, in which 1602 reproducible and distinguishable bands were included with an average of 114 bands per primer. The Jaccard’s coefficient demonstrated a similarity range from 0.438 to 0.884 between the strains and the twenty-two A. caldus strains studied were clustered into three groups at 0.6 similarity level by UPGMA clustering. The results acquired from principal component analysis (PCA) showed that most of strains from similar geochemistry clustered together. Additionally, Mantel test results indicated that the geochemical parameters positive impacted the genomic diversity. This study enlarges our knowledge about the variablility of A. caldus and the theory of microbial dispersal.