Aug 12, 2014

Evidence of novel phylogenetic lineages of methanogenic archaea from hypersaline microbial mats

Microbial Ecology
José Q García-MaldonadoAlejandro López-Cortés

Abstract

Methanogenesis in hypersaline and high-sulfate environments is typically dominated by methylotrophic methanogens because sulfate reduction is thermodynamically favored over hydrogenotrophic methanogenesis in these environments. We characterized the community composition of methanogenic archaea in both unmanipulated and incubated microbial mats from different hypersaline environments in Baja California Sur, Mexico. Clone libraries of methyl coenzyme-M reductase (mcrA) sequences and DGGE band patterns of 16S rRNA and mcrA sequences showed that the methanogen community in these microbial mats is dominated by methylotrophic methanogens of the genus Methanohalophilus. However, phylogenetic analyses of mcrA sequences from these mats also revealed two new lineages corresponding to putative hydrogenotrophic methanogens related with the strictly hydrogenotrophic order Methanomicrobiales. Stimulated methane production under decreased salinity and sulfate concentrations also suggested the presence of hydrogenotrophic methanogens in these samples. The relative abundance of mcrA gene and transcripts, estimated by SYBR green I qPCR assays, suggested the activity of different phylogenetic groups of methanogens, including the two novel cluster...Continue Reading

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  • Citations8

References

Mentioned in this Paper

Real-Time Polymerase Chain Reaction
Methanomicrobiales
Archaea
Methanohalophilus
Phylogeny
Methanobacteria
Salinity
Microbial
Methanogenesis
Sulfate Reduction

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