Rugamonas aquatica sp. nov. and Rugamonas rivuli sp. nov., isolated from a subtropical stream in PR China.

Two Gram-stain-negative, catalase- and oxidase-positive, rod-shaped, motile strains (FT29WT and FT103WT) were isolated from a subtropical stream in PR China. Comparisons based on 16S rRNA gene sequences showed that strains FT29WT and FT103WT showed 98.7 and 98.6 % 16S rRNA gene sequence similarities to Rugamonas rubra CCM 3730T as their closest neighbour, respectively. The calculated pairwise OrthoANIu values between strain R. rubra CCM 3730T and strains FT29WT and FT103WT were all 81.4 %. The respiratory quinone of strains FT29WT and FT103WT was determined to be Q-8. The major fatty acids were C16 : 1 ω7c, C16 : 0 and C12 : 0. The polar lipids of strain FT103WT included phosphatidylethanolamine, phosphatidylglycerol and one unidentified phospholipid, but strain FT29WT did not contain phosphatidylglycerol. The genome sizes of strains FT29WT and FT103WT were 7.23 and 6.84 Mbp with G+C contents of 63.8 and 63.9 %, respectively. Although the pairwise OrthoANIu value between strains FT29WT and FT103WT was 95.2 % which located in the transition region of species demarcation, the dissimilarities in the aspects of phenotypic, biochemical and genotypic characteristics supported these two strains should belong to the different species within genus Rugamonas, for which the names Rugamonas aquatica sp. nov. (type strain FT29WT=GDMCC 1.1643T=KACC 21316T) and Rugamonas rivuli sp. nov. (type strain FT103WT=GDMCC 1.1685T=KACC 21477T) are proposed.