Peculiar Archaea Found in Japanese Paddy Soils†.

Archaeal 16S rDNA clones retrieved from paddy soil DNA were sequenced. Among 100 clones, 88 clones were assigned to methanogens and nine clones were assigned to crenarchaeota. However, three of the nine clones were phylogenetically far from the cultured crenarchaeota and closely related to marine planktonic archaea. The other three clones showed extremely novel 16S rDNA sequences and were phylogenetically far from both Crenarchaeota and Euryarchaeota. This paper reports the ubiquitous presence of crenarchaeotal and extremely novel clones in paddy soils.