Undibacterium baiyunense sp. nov., Undibacterium curvum sp. nov., Undibacterium fentianense sp. nov., Undibacterium flavidum sp. nov., Undibacterium griseum sp. nov., Undibacterium hunanense sp. nov., Undibacterium luofuense sp. nov., Undibacterium nitidum sp. nov., Undibacterium rivi sp. nov., Undibacterium rugosum sp. nov. and Undibacterium umbellatum sp. nov., isolated from streams in China

Twelve Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and motile strains (CY7W(T), CY18W(T), CY22W(T), FT31W(T), FT137W(T), FT147W(T), BYS50W, BYS107W(T), LFS511W(T), LX15W(T), LX22W(T) and NL8W(T)) were isolated from streams in China. Comparisons based on 16S rRNA gene sequences indicated that these strains take species of genus Undibacterium as close neighbours. The reconstructed phylogenetic and phylogenomic trees also showed that these strains cluster with species of genus Undibacterium together. The genome G+C contents of these strains were in the range of 45.3 to 53.3 mol%. The calculated pairwise OrthoANIu values and digital DNA-DNA hybridization values among these strains and related strains were in the range of 70.4 to 94.1% and 19.3 to 55.3% except that the values between strains CY7W(T) and BYS50W were 99.0 and 91.8%, respectively. Q-8 was their predominant respiratory quinone. C-16:1 omega 7c and C-16:0 were their major fatty acids. Their polar lipids profiles were similar, including phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and two kinds of unidentified aminolipids. Combining polyphasic taxonomic characteristics and phylogenetic relationships, twelve strains should represent eleven independent novel species of genus Undibacterium, for which the names Undibacterium baiyunense sp. nov. (type strain BYS107W(T)=GDMCC 1.2453(T)=KCTC 82653(T)), Undibacterium curvum sp. nov. (type strain CY22W(T)=GDMCC 1.1906(T)=KACC 21951(T)), Undibacterium fentianense sp. nov. (type strain FT137W(T)=GDMCC 1.2456(T)=KCTC 82656(T)), Undibacterium flavidum sp. nov. (type strain LX15WT=GDMCC 1.1910(T)=JCM 34286(T)), Undibacterium griseum sp. nov. (type strain FT31W(T)=GDMCC 1.1908(T)=KACC 21953(T)), Undibacterium hunanense sp. nov. (type strain CY18W(T)=GDMCC 1.1904(T)=KACC 21949(T)), Undibacterium luofuense sp. nov. (type strain LFS511W(T)=GDMCC 1.2458(T)=KCTC 82658(T)), Undibacterium nitidum sp. nov. (type strain LX22W(T)=GDMCC 1.1912(T)=KACC 21957(T)), Undibacterium rivi sp. nov. (type strain FT147W(T)=GDMCC 1.2457(T)=KCTC 82657(T)), Undibacterium rugosum sp. nov. (type strain CY7W(T)=GDMCC 1.1903(T)=KACC 21961(T)) and Undibacterium umbellatum sp. nov. (type strain NL8W(T)=GDMCC 1.1915(T)=KACC 21960(T)) are proposed.