Application of a recN sequence similarity analysis to the identification of species within the bacterial genus Geobacillus

Abstract

Full-length recN and 16S rRNA gene sequences were determined for a collection of 68 strains from the thermophilic Gram-positive genus Geobacillus, members of which have been isolated from geographically and ecologically diverse locations. Phylogenetic treeing methods clustered the isolates into nine sequence similarity groups, regardless of which gene was used for analysis. Several of these groups corresponded unambiguously to known Geobacillus species, whereas others contained two or more type strains from species with validly published names, highlighting a need for a re-assessment of the taxonomy for this genus. For taxonomic analysis of bacteria related at a genus, species or subspecies level, recN sequence comparisons had a resolving power nearly an order or magnitude greater than 16S rRNA gene comparisons. Mutational saturation rendered recN comparisons much less powerful than 16S rRNA gene comparisons for analysis of higher taxa, however. Analysis of recN sequences should prove a powerful tool for assigning strains to species within Geobacillus, and perhaps within other genera as well.

Proposed minimal standards for describing new taxa of aerobic, endospore-forming bacteria

“…Zeigler (2005) found recN sequence similarities to yield clustering patterns among Geobacillus very similar to those obtained with 16S rRNA gene sequences, and Mota et al (2005) obtained clustering patterns for Paenibacillus based upon rpoB sequence comparisons that were similar to those obtained with 16S rRNA gene sequences. Wang et al (2007a, b) included gyrB sequence comparisons in studies of the B. subtilis group and demonstrated the synonymy of Bacillus axarquiensis and Bacillus malacitensis with Bacillus mojavensis, and Cerritos et al (2008) included recA sequence comparisons in the work that led to the proposal of Bacillus coalhuilensis.…”

Isolation and characterization of arsenic resistant Geobacillus kaustophilus strain from geothermal soils

“…To further clarify the taxonomic position of Geobacillus strain A1, the region encompassing its recN gene was sequenced. Zeigler [28] proposed a correlation between DNA relatedness assessed by DNA-DNA hybridization and the similarity of recN nucleotide sequences. A comparison between the G. kaustophilus HTA426 recN sequence and the homolog sequence of strain A1 showed a similarity >99.9%.…”

Genotyping of Present-Day and Historical Geobacillus Species Isolates from Milk Powders by High-Resolution Melt Analysis of Multiple Variable-Number Tandem-Repeat Loci

“…Furthermore, the number of loci that could be amplified in all strains may be low since the technique genotypes strains of Geobacillus at a genus level rather than at a single species level. The genus Geobacillus has been known to be highly conserved, and 16S rRNA gene sequences have failed to accurately identify different species (22,26,41,43). Identification solely on the basis of 16S rRNA genes for Geobacillus spp.…”