The production and consumption of methane by microorganisms play a major role in the global carbon cycle. Although these processes can occur in a range of environments, from animal guts to the deep ocean, these metabolisms are confined to the Archaea. Evans et al. used metagenomics to assemble two nearly complete archaeal genomes from deep groundwater methanogens (see the Perspective by Lloyd). The two reconstructed genomes are members of the recently described Bathyarchaeota and not the phylum to which all previously known methane-metabolizing archaea belonged.
Textbooks on methane-metabolising organisms might have to be rewritten after researchers in a University of Queensland-led international project on 23 October announced the discovery of two new organisms.
"We sampled the microorganisms in the water from a deep coal seam aquifer 600m below the earth's surface in the Surat Basin, near Roma, Queensland, and reconstructed genomes of organisms able to perform methane metabolism," Associate Professor Tyson said.
"Traditionally, these type of methane-metabolising organisms occur within a single cluster of microorganisms called Euryarchaeota. "This makes us wonder how many other types of methane-metabolising microorganisms are out there?"
Dr Tyson's group discovered novel methane metabolising organisms belonging to a group of microorganisms, called the Bathyarchaeota - an evolutionarily diverse group of microorganisms found in a wide range of environments, including deep-ocean and freshwater sediments.
"To use an analogy, the finding is like knowing about black and brown bears, and then coming across a giant panda," Dr Tyson said.
"They have some basic characteristics in common, but in other ways these they are fundamentally different.
"The significance of the research is that it expands our knowledge of diversity of life on Earth and suggests we are missing other organisms involved in carbon cycling and methane production."
The discovery of the novel methane-metabolising microorganisms was made using techniques that sequence DNA on a large scale and assemble these sequences into genomes using advanced computational tools, many of which were developed at The Australian Centre for Ecogenomics over the past 24 months.
The research, titled Methane metabolism in the archaeal phylum Bathyarchaeota revealed by genome-centric metagenomics, was published in Science.
"Methane metabolism in the archaeal phylum Bathyarchaeota revealed by genome-centric metagenomics." Science 23 October 2015: DOI: 10.1126/science.aac7745
Source: University of Queensland | Phys.