@article{mbs:/content/journal/ijsem/10.1099/ijs.0.65571-0, author = "Sakai, Sanae and Imachi, Hiroyuki and Hanada, Satoshi and Ohashi, Akiyoshi and Harada, Hideki and Kamagata, Yoichi", title = "Methanocella paludicola gen. nov., sp. nov., a methane-producing archaeon, the first isolate of the lineage ‘Rice Cluster I’, and proposal of the new archaeal order Methanocellales ord. nov.", journal= "International Journal of Systematic and Evolutionary Microbiology", year = "2008", volume = "58", number = "4", pages = "929-936", doi = "https://doi.org/10.1099/ijs.0.65571-0", url = "https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.65571-0", publisher = "Microbiology Society", issn = "1466-5034", type = "Journal Article", keywords = "RC-I, Rice Cluster I", abstract = "A novel mesophilic, hydrogenotrophic methanogen, strain SANAET, was isolated from an anaerobic, propionate-degrading enrichment culture, which was originally established from rice paddy soil. The cells were non-motile, Gram-negative and rod-shaped (1.8–2.4 μm long by 0.3–0.6 μm wide). Growth of strain SANAET was observed at 25–40 °C, with an optimum temperature range for growth of 35–37 °C. The pH range for growth was 6.5–7.8, with an optimum at pH 7.0. The salinity range for growth was 0–1 g NaCl l−1 (0–17 mM). The isolate was able to utilize H2/CO2 and formate for growth and methane production. The G+C content of the genomic DNA was 56.6 mol%. Based on comparative 16S rRNA gene sequence analysis, strain SANAET was affiliated with a clone lineage of the Archaea, Rice Cluster I (RC-I), placing it between the orders Methanosarcinales and Methanomicrobiales within the class ‘Methanomicrobia’. 16S rRNA gene sequence similarities between strain SANAET and members of Methanosarcinales were in the range 80.0–82.8 %, and those between the strain and members of Methanomicrobiales ranged from 77.5 to 82.4 %. In addition to 16S rRNA gene analysis, sequence analysis of the mcrA gene (encoding the α subunit of methyl-coenzyme M reductase, a key enzyme in the methane production pathway) also showed that strain SANAET was affiliated with the RC-I lineage. Here, we propose the name Methanocella paludicola gen. nov., sp. nov. for the isolate, the first of the RC-I lineage. The type strain is SANAET (=JCM 13418T=NBRC 101707T=DSM 17711T). In addition, we also propose the status of order for the RC-I lineage, for which we propose the name Methanocellales ord. nov.", }