PARENT SESSION
Poster Session #35: Decomposition and Soil Respiration.
Thursday, August 9, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall
17
Phylogeny and relationships of a probable new group of bacteria based on 16S rRNA phylogeny.
Lau, Evan1, Graham, Linda2, 1 2
ABSTRACT- Microorganisms mediate many of the biogeochemical processes in peatlands. Methane-oxidizing bacteria (MOB) are responsible for biological methanotrophy, the destruction of methane gas produced in peatlands. PCR primers specific for type II MOB were used in PCR-ARISA (automated rRNA intergenic spacer analysis) in a search for MOB in a northern Wisconsin peatland. Community DNA samples extracted from peat and living Sphagnum tissues were used as templates in PCR-ARISA. Cloning, sequencing and phylogenetic analysis of these PCR products revealed eight partial 16S rRNA gene sequences, all representing novel taxa, and forming a distinct phylogenetic cluster. They are closely related to Azospirillum/Magnetospirillum/Phaeospirillum and other environmental clones belonging to the alpha subdivision bacteria. These eight clones are only distantly related to known type II MOB. Although detected in a methane-rich environment, their physiology is unknown. Re-PCR amplification of clone DNA using the same primers, followed by ARISA, established the position of peaks in band patterns. Polar ordination (Bray-Curtis, 1957) and Reciprocal Averaging (RA) multivariate analyses indicated little correlation (i.e. -0.5 < r < 0.5) between dates of sampling, difference in topography and habitat (within Sphagnum moss or in peat). One clone, BP9 (with one exception), was ubiquitous at all four sites, in both peat and Sphagnum moss, and throughout the four month sampling period.
KEY WORDS: peat bog, 16S RNA phylogeny, Sphagnum moss, alpha subdivision proteobacteria