Asticcacaulis aquaticus sp. nov., Asticcacaulis currens sp. nov. and Asticcacaulis machinosus sp. nov., isolated from streams in PR China

Three Gram-stain-negative, aerobic, rod-shaped, stalked and motile strains with a polar flagellum (BYS171W T , DXS10W T and LKC15W T ) were isolated from streams in PR China. Comparisons based on 16S rRNA gene sequences showed that strains BYS171W T and DXS10W T had the highest 16S rRNA gene sequence similarities (98.1 and 98.6 %, respectively) to Asticcacaulis excentricus CB 48 T , and strain LKC15W T showed 99.6 % similarity to Asticcacaulis endophyticus ZFGT-14 T . These three strains showed 16S rRNA gene sequence similarities of less than 96.9 % to other species of the genus Asticcacaulis . A phylogenetic tree reconstructed based on 16S rRNA gene sequences also showed that strains BYS171W T and DXS10W T took A. excentricus CB 48 T as their closest neighbour, and strain LKC15W T formed a tight cluster with A. endophyticus ZFGT-14 T . The phylogenomic tree also showed that these three strains belong to the genus Asticcacaulis and form a distinct clade with the species of the genus Asticcacaulis . The major cellular fatty acids of these three strains were summed feature 3 (C 16 : 1 ω 7 c and/or C 16 : 1 ω 6 c ), summed feature 8 (C 18 : 1 ω 7 c and/or C 18 : 1 ω 6 c ), C 16 : 0 and 11-methyl C 18 : 1 ω 7 c . Their polar lipids mainly consisted of phosphatidylglycerol, unidentified glycolipids and nitrogen-containing phosphoglycolipids. The calculated OrthoANIu and digital DNA–DNA hybridization values among strains BYS171W T , DXS10W T , LKC15W T and other related strains were less than 87.2 % and 34.0 %, respectively, indicating that these three strains should represent three independent novel species of the genus Asticcacaulis , for which the names Asticcacaulis aquaticus sp. nov. (type strain BYS171W T =GDMCC 1.3226 T =KCTC 92612 T ), Asticcacaulis currens sp. nov. (type strain DXS10W T =GDMCC 1.3224 T =KCTC 92543 T ) and Asticcacaulis machinosus sp. nov. (type strain LKC15W T =GDMCC 1.3225 T =KCTC 92544 T ) are proposed.