Candidate division BD: phylogeny, distribution and abundance in soil ecosystems

Area of Science:

• Microbiology
• Environmental Science
• Molecular Biology

Background:

• A novel bacterial group, designated BD, was recently identified.
• Understanding the phylogenetic placement and ecological distribution of novel bacterial groups is crucial for microbial ecology.

Purpose of the Study:

• To determine the phylogenetic status of bacterial group BD.
• To investigate the abundance and distribution of BD group 3 in Wyoming shortgrass steppe soils.

Main Methods:

• Oligonucleotide primers were used to amplify partial 16S rDNA sequences from diverse soil samples.
• Phylogenetic analysis was performed on 34 BD group sequences.
• Quantitative PCR (qPCR) with intercalating dye was employed to quantify BD group 3 16S rDNA.

Main Results:

• Phylogenetic analysis supported division-level status for bacterial group BD, with at least 3 subdivision-level groups identified.
• Sequence divergence within the BD group was comparable to bacterial division-level lineages.
• BD group 3 16S rDNA averaged 3 x 10(8) copies per gram of soil in Wyoming shortgrass steppe soils.
• No significant correlation was found between BD group 3 abundance and soil organic matter, inorganic N, or pH.
• BD group 3 was estimated to represent 0.75%–10.7% of the total microbial population.

Conclusions:

• Bacterial group BD is a distinct phylogenetic lineage with significant environmental distribution.
• BD group 3 is abundant in Wyoming shortgrass steppe soils, comprising a notable portion of the microbial community.
• Further research is warranted to understand the ecological role of this widespread bacterial group.