Phylogeny in aid of the present and novel microbial lineages: diversity in Bacillus.

2009-02-12
PloS one 4(2)

PubMed: 19212464
DOI: 10.1371/journal.pone.0004438

Study Design

Sample size: n = 2,611
Population: 16S rRNA sequences of Bacillus anthracis (153 strains), B. cereus (211 strains), B. thuringiensis (108 strains), B. subtilis (271 strains), B. licheniformis (131 strains), B. pumilus (83 strains), B. megaterium (47 strains), B. sphaericus (42 strains), B. clausii (39 strains) and B. halodurans (36 strains)
Methods: Phylogenetic segregation of 1121, 16S rDNA sequences of 10 different Bacillus species in to 89 clusters; development of a phylogenetic frame work of 34 representative sequences; signature sequences and in silico restriction enzyme analysis specific to the 10 Bacillus species

Bacillus represents microbes of high economic, medical and biodefense importance. Bacillus strain identification based on 16S rRNA sequence analyses is invariably limited to species level. Secondly, certain discrepancies exist in the segregation of Bacillus subtilis strains. In the RDP/NCBI databases, out of a total of 2611 individual 16S rDNA sequences belonging to the 175 different species of the genus Bacillus, only 1586 have been identified up to species level. 16S rRNA sequences of Bacillus anthracis (153 strains), B. cereus (211 strains), B. thuringiensis (108 strains), B. subtilis (271 strains), B. licheniformis (131 strains), B. pumilus (83 strains), B. megaterium (47 strains), B. sphaericus (42 strains), B. clausii (39 strains) and B. halodurans (36 strains) were considered for generating species-specific framework and probes as tools for their rapid identification. Phylogenetic segregation of 1121, 16S rDNA sequences of 10 different Bacillus species in to 89 clusters enabled us to develop a phylogenetic frame work of 34 representative sequences. Using this phylogenetic framework, 305 out of 1025, 16S rDNA sequences presently classified as Bacillus sp. could be identified up to species level. This identification was supported by 20 to 30 nucleotides long signature sequences and in silico restriction enzyme analysis specific to the 10 Bacillus species. This integrated approach resulted in identifying around 30% of Bacillus sp. up to species level and revealed that B. subtilis strains can be segregated into two phylogenetically distinct groups, such that one of them may be renamed.

Research Insights

Supplement	Dose	Health Outcome	Effect Type	Effect Size	Source
Bacillus clausii SC-109	—	Improved Identification of Bacillus clausii	Beneficial	Small	View source 16S rRNA sequences of ... B. clausii (39 strains) ... were considered for generating species-specific framework and probes as tools for their rapid identification.