New perspective on uncultured bacterial phylogenetic division OP11

Area of Science:

• Microbiology
• Environmental Science
• Molecular Biology

Background:

• Organisms of the OP11 candidate division of Bacteria were previously detected only through rRNA-based surveys of environmental samples.
• Preliminary data suggested these OP11 organisms are abundant, widespread, and phylogenetically diverse in natural environments.

Purpose of the Study:

• To comprehensively document the phylogenetic breadth and environmental distribution of the OP11 bacterial division.
• To identify and characterize novel bacterial divisions related to OP11.

Main Methods:

• Conducted molecular analyses on 17 environmental DNA samples.
• Utilized PCR with primers targeting five OP11 subdivisions.
• Analyzed rRNA gene sequences from 27 clonal libraries across 14 environments, including full sequencing of 99 new unique sequences.

Main Results:

• Determined 99 new unique rRNA gene sequences, significantly expanding the known diversity within the OP11 division.
• Identified two novel candidate bacterial divisions: OP11-derived 1 (OD1) and Sulphur River 1 (SR1).
• Confirmed the widespread environmental distribution of the OD1, OP11, and SR1 divisions.

Conclusions:

• The discovery of OD1 and SR1 divisions broadens our understanding of bacterial diversity.
• The widespread distribution of OD1, OP11, and SR1 suggests significant biogeochemical roles in their respective environments.
• The generated sequences serve as molecular signatures for identifying these novel bacteria and may guide future culturing efforts.