Mucilaginibacter glaciei sp. nov. and Mucilaginibacter pankratovii sp. nov., isolated from a glacier on the Tibetan Plateau

Mucilaginibacter aquariorum sp. nov., Isolated from Fresh Water

A Gram-stain-negative, rod-shaped bacterial strain, JC4^T, was isolated from a freshwater sample and determined the taxonomic position. Initial identification based on 16S rRNA gene sequences revealed that strain JC4^T is affiliated to the genus Mucilaginibacter with a sequence similarity of 97.97% to Mucilaginibacter rigui WPCB133^T. The average nucleotide identity and digital DNA-DNA hybridization values between strain JC4^T and Mucilaginibacter species were estimated below 80.92% and 23.9%, respectively. Strain JC4^T contained summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and iso-C_15:0 as predominant cellular fatty acids. The dominant polar lipids were identified as phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, and two unidentified lipids. The respiratory quinone was MK-7. The genomic DNA G+C content of strain JC4^T was determined to be 42.44%. The above polyphasic evidences support that strain JC4^T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter aquariorum sp. nov. is proposed. The type strain is JC4^T (= KCTC 92230^T = LMG 32715^T).

Mucilaginibacter aurantiaciroseus sp. nov. and Mucilaginibacter flavidus sp. nov., isolated from Renlongba glacier on the Tibetan Plateau

Strains RB4R14^T and RT5R15^T, two Gram-stain-negative, aerobic, rod-shaped, non-motile bacteria, were isolated from ice and cryoconite of Renlongba glacier, respectively, on the Tibetan Plateau, PR China. The results of phylogenetic analysis based on 16S rRNA genes indicated that strains RB4R14^T and RT5R15^T belonged to the genus Mucilaginibacter with the highest similarities to Mucilaginibacter rigui WPCB133^T (98.78 %) and Mucilaginibacter xinganensis BJC16-A31^T (97.64 %), respectively. The genomic DNA G+C contents of strains RB4R14^T and RT5R15^T were 42.8 and 43.1 mol%, respectively. The digital DNA-DNA hybridization values between strains RB4R14^T, RT5R15^T and their close relatives were below 31.9 and 17.4 %, respectively. The average nucleotide identity values between the two novel strains and their close relatives were 79.5-82.0 and 77.9-79.3 % respectively, indicating the novelty of the two isolates at a species level. The two novel strains contained MK-7 as the major menaquinone, and summed feature 3 (comprising C_16 : 1  ω7c and/or C_16 : 1  ω6c), iso-C_15 : 0 and iso-C_17 : 0-3OH as the major fatty acids. The major polar lipid of the two novel strains were phosphatidylethanolamine. Based on phenotypic, chemotaxonomic and phylogenetic results, we propose two novel species, Mucilaginibacter aurantiaciroseus sp. nov. (RB4R14^T=CGMCC 1.11911^T=NBRC 114020^T) and Mucilaginibacter flavidus sp. nov. (RT5R15^T=CGMCC 1.23117^T=NBRC 113930^T).

Mucilaginibacter rivuli sp. nov., isolated from a water rivulet

Strain HMF5004T was isolated from a rivulet located in Yongin, Republic of Korea. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain HMF5004T belonged to the genus Mucilaginibacter . Strain HMF5004T was closely related to Mucilaginibacter paludis (97.7%) and Mucilaginibacter gracilis (97.2%). The values of average nucleotide identity and digital DNA–DNA hybridization between strain HMF5004T and M. paludis were 72.8 and 19.2 %, respectively. Cells of strain HMF5004T were Gram-stain-negative, rod-shaped, non-motile, catalase-positive and oxidase-positive. The DNA G+C content of strain HMF5004T was 42.4 mol%. Strain HMF5004T had menaquinone-7 as a major quinone. The major cellular fatty acids included iso-C15 : 0, summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c) and anteiso-C15 : 0. The polar lipids of strain HMF5004T contained phosphatidylethanolamine, five unidentified aminolipids, one unidentified aminophospholipid and four unidentified polar lipids. On the basis of the evidence presented in this polyphasic taxonomic study, strain HMF5004T is considered to represent a novel species for which the name Mucilaginibacter rivuli sp. nov. is proposed. The type strain is HMF5004T (=KCTC 82633T=NBRC 115091T).

Caulobacter endophyticus sp. nov., an endophytic bacterium harboring three lasso peptide biosynthetic gene clusters and producing indoleacetic acid isolated from maize root

A novel Gram-stain-negative, aerobic and rod-shaped bacterium with a single polar flagellum or a stalk at the end of the cell, was isolated from maize roots in the Fangshan District of Beijing, People's Republic of China. The new strain designated 774^T produced indole acetic acid (IAA). The 16S rRNA gene sequence analysis indicated that strain 774^T belongs to the genus Caulobacter and is closely related to Caulobacter flavus RHGG3^T, Caulobacter zeae 410^Tand Caulobacter radices 695^T, all with sequence similarities of 99.9%. The genome size of strain774^T was 5.4 Mb, comprising 5042 predicted genes with a DNA G+C content of 68.7%.Three striking lasso peptide biosynthetic gene clusters and two IAA synthesis genes belonging to the TPM pathway were also found in the genome of strain 774^T. The average nucleotide identity values and digital DNA-DNA hybridization values of the strain774^T with its closely phylogenetic neighbours were less than 91.5% and 45.0%, respectively, indicating a new Caulobacter species. The major fatty acids of strain774^T were identified as C16: 0 (27.7%), summed feature 3 (C16: 1ω6c and/or C16: 1ω7c) (12.6%) and summed feature 8 (C18: 1ω7c and/or C18: 1ω6c) (42.9%).The major polar lipids consisted of phosphatidyl-glycerol and glycolipids. The predominant ubiquinone was identified as Quinone 10. Based on the polyphasic characterization, strain 774^T represents a novel species of the genus Caulobacter, for which the name Caulobacter endophyticus sp. nov. is proposed with 774^T (= CGMCC 1.16558^T = DSM 106777^T) as the type strain.