Two Metagenome-Assembled Genomes of Hydrogen-Dependent Methanomassiliicoccales Methanogens from the Zoige Wetland of the Tibetan Plateau

Wetlands in the Tibetan Plateau play a crucial role in global carbon cycling. Here, we report the metagenome-assembled genomes (MAGs) of two hydrogen-dependent methanogens from the Zoige wetland of the Tibetan Plateau. The novel species belong to Methanomassiliicoccales, the seventh euryarchaeal methanogenic order.

M ethanogens are a group of archaea that control methane production in wetlands. Wetlands in the Tibetan Plateau are the major methane emission center in China (1). The genome research on uncultured methanogens in this extreme environment is of great importance in explaining the methane cycle in high-altitude wetlands.
Previously, extant methanogenic organisms were thought to belong exclusively to the phylum Euryarchaeota (2, 3), although more recently this assertion has been challenged by reports about the Bathyarchaeota (4, 5), Verstraetearchaeota (3, 6), and newly discovered Cyanobacteria (7,8) phyla. Methanogens from the Methanomassiliicoccales order are called the seventh order of methanogens and are widely distributed in various environments (9). Here, we announce two metagenome-assembled genomes (MAGs) of novel Methanomassiliicoccales species with medium completeness.
Two sediment cores from the Flower Lake National Reserve of the Zoige wetland (102°529E, 33°569N) were sampled using sampling equipment (10 cm in diameter). The sampling site was water saturated, and the standing water depth was about 20 cm. Sediment cores were mixed thoroughly and kept at 280°C before use. DNA was extracted from the two sediment samples using the FastDNA spin kit for soil (MP Biomedicals, Cleveland, OH, USA) following the manufacturer's instructions. A shotgun library was prepared with the NEBNext kit. Sequencing was completed on an Illumina HiSeq 2 Â 150-bp platform. The average amount of metagenomic raw data for each sample was approximately 30 Gbp.
The two MAGs contain all genes required for hydrogen-dependent reduction of methanol to methane, as proposed for other Methanomassiliicoccales strains (18). This announcement provides the basis for isolating this clade from environments.
Data availability. The Methanomassiliicoccales genome sequences have been deposited in GenBank under the accession numbers JACXTO000000000 and JACXTP000000000. The versions described here are the first versions. All metagenomic data generated from this announcement are available under BioProject number PRJNA644254. Metagenomic bins can be found under BioSample numbers SAMN15455434 and SAMN15455435.

ACKNOWLEDGMENTS
This work was supported by the National Natural Science Foundation of China (grants 41977196 and 91951103), the China Ocean Mineral Resources R&D Association (grant DY135-B-02), and the Key Program of Frontier Sciences of the Chinese Academy of Sciences (grant QYZDB-SSW-SMC008).