Devosia confluentis sp. nov., isolated from the junction between the ocean and a freshwater lake, and reclassification of two Vasilyevaea species as Devosia enhydra comb. nov. and Devosia mishustinii comb. nov

Devosia aquimaris sp. nov., isolated from seawater of the Changjiang River estuary of China

A gram-stain-negative, aerobic, rod-shaped bacterium strain CJK-A8-3T was isolated from a polyamine-enriched seawater sample collected from the Changjiang River estuary of China. The colonies were white and circular. Strain CJK-A8-3T grew optimally at 35 °C, pH 7.0 and 1.5% NaCl. Its polar lipids contained phosphatidylglycerol, phosphatidic acid, unidentified glycolipids, and a combination of phospholipids and glycolipids. The respiratory quinone was ubiquinone-10, and its main fatty acids were C16:0, 11-methyl C18:1ω7c and Summed Feature 8 (including C18:1ω7c/C18:1ω6c). The phylogenetic tree based on 16S rRNA genes placed strain CJK-A8-3T in a new linage within the genus Devosia. 16S rRNA gene sequence of strain CJK-A8-3T showed identities of 98.50% with Devosia beringensis S02T, 98.15% with D. oryziradicis, and 98.01% with D. submarina JCM 18935T. The genome size of strain CJK-A8-3T was 3.81 Mb with the DNA G + C content 63.9%, higher than those of the reference strains (60.4-63.8%). The genome contained genes functional in the metabolism of terrigenous aromatic compounds, alkylphosphonate and organic nitrogen, potentially beneficial for nutrient acquirement and environmental remediation. It also harbored genes functional in antibiotics resistance and balance of osmotic pressure, enhancing their adaptation to estuarine environments. Both genomic investigation and experimental verification showed that strain CJK-A8-3T could be versatile and efficient to use diverse organic nitrogen compounds as carbon and nitrogen sources. Based on phenotypic, chemotaxonomic, phylogenetic and genomic characteristics, strain CJK-A8-3T was identified as a novel Devosia species, named as Devosia aquimaris sp. nov. The type strain is CJK-A8-3T (= MCCC 1K06953T = KCTC 92162T).

Devosia lacusdianchii sp. nov., an attached bacterium inhibited by metabolites from its symbiotic Microcystis

A novel alphaproteobacterial strain JXJ CY 41T was isolated from a culture mass of Microcystis, collected from Lake Dianchi, south-west, China. Strain JXJ CY 41T was gram-strain-negative, aerobic, motile, with rod-shaped cells (0.4-1.0 × 1.7-3.5 μm). It was positive for catalase and starch hydrolysis, negative for oxidase and hydrolysis of Tweens (20, 40, and 80). Growth occurred at 10-44 °C, pH 5.0-10.0, and 0-5.0% (w/v) NaCl. Major fatty acids included C16:0 (28.1%), 11-methyl C18:1 ω7c (36.7%) and C18:1 ω7c (20.8%). Q10 was the sole ubiquinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, glycolipid, and an unidentified lipid. The DNA G + C content was 63.1%. Its 16S rRNA gene sequence showed high similarities with Devosia oryziradicis G19T (99.5%; not validly published), D. yakushimensis Yak96BT (98.3%) and D. ginsengisoli Gsoil 520T (98.1%), and less than 98.1% similarities with other members of the genus Devosia. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain JXJ CY 41T and its 5 closest similar strains were 19.9-24.1% and 75.7-80.5%, respectively. Based on the data above, strain JXJ CY 41T was identified as a novel species of the genus Devosia, for which the epithet Devosia lacusdianchii sp. nov. was proposed. The type strain is JXJ CY 41T (= KCTC 72812T = CGMCC 1.17502T). Strain JXJ CY 41T exhibited different interactions with Microcystis aeruginosa FACHB-905 (Maf) under different conditions, and Maf could control the bacterial cellular density by secreting unknown specific chemical compounds according to its nutritional requirements.

Devosia beringensis sp. nov., isolated from surface sediment of the Bering Sea

Strain S02^T was isolated from a surface sediment sample collected from the Bering Sea (64.3361° N, 170.9541° W). The cells were Gram-stain-negative, motile and rod-shaped. The temperature range for growth was 4-25 °C and the pH for growth was 5.5-9.0, with optimum growth occurring at 20-25 °C and pH 7.0-8.0. Growth occurred in the presence of 0-7 % (w/v) NaCl (optimum, 2-5 %). Strain S02^T had menaquinone-8 as the major respiratory quinone and summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c), C16:0, C_17 : 0 cyclo, summed feature 3 (C_16 : 1  ω7c /C_16 : 1  ω7c), C_17 : 0 and C_18 : 0 as major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and two glycolipids. The genomic DNA G+C content was approximately 63.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S02^T belonged to the genus Devosia. Strain S02^T showed the highest sequence similarities to Devosia psychrophila Cr7-05^T (97.5 %), Devosia naphthalenivorans CM5-1^T (97.7 %), Devosia submarina KMM 9415^T (97.4 %), Devosia epidermidihirudinis E84^T (97.44 %), Devosia euplotis LIV5^T (97.1 %) and Devosia limi DSM 17137^T (96.7 %). On the basis of phylogenetic analyses and phenotypic characteristics, a novel species of the genus Devosia, Devosia beringensis sp. nov., is proposed, with the type strain S02^T (=JCM 33772=CCTCC AB 2019343).

Devosia aurantiaca sp. nov., Isolated from Mountain Soil and Proposal of Albitalea gen. nov. to Replace the Illegitimate Prokaryotic Genus Name Geomonas Khan et al. 2020

Strain H239^T, a gram-negative, strictly aerobic, and oxidase-positive, and catalase-negative bacterium, was isolated from mountain soil in Gangwon-do of South Korea. Colonies were orange colored, and cells were motile rods with a single polar flagellum. Growth was observed between 25 and 30 °C (optimum, 30 °C), between pH 7.0 and pH 9.0 (optimum, pH 7.5), and in the presence of 0-1.5% (w/v) NaCl (optimum 0.5-1%). Ubiquinone-10 was detected as the sole respiratory quinone. The major fatty acids (>10%) of strain H239^T were C_18:1 ω7c, C_18:0, and C_16:0. The polar lipids detected from strain H239^T consisted of two unidentified glycolipids, two unidentified phospholipids, and three unidentified polar lipids. The G+C content of strain H239^T based on its genome sequence was 62.0 mol%. Comparative 16S rRNA gene sequence analysis indicated that strain H239^T was most closely related to Devosia chinhatensis IPL18^T (97.7%), Devosia submarina KMM 9415^T (97.7%), and Devosia yakushimensis Yak96B^T (97.3%). Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain H239^T formed a distinct phyletic lineage as a new species within the genus Devosia. Based on its physiological, chemotaxonomic, and molecular properties, strain H239^T represents a novel species of the genus Devosia, for which the name Devosia aurantiaca sp. nov. is proposed. The type strain is H239^T (=KACC 21662^T=JCM 33930^T). In addition, because the prokaryotic genus name Geomonas Khan et al. 2020 is a later homonym of Geomonas Xu et al. 2020, the name is illegitimate (Principle 6 in the International Code of Nomenclature of Prokaryotes). Therefore, we propose to replace the problematic prokaryotic names Geomonas and Geomonas soli with Albitalea with Albitalea terrae, respectively.

Devosia ginsengisoli sp. nov., isolated from ginseng cultivation soil

A Gram-stain-negative, strictly aerobic, motile, ivory-coloured and rod-shaped bacterium (designated Gsoil 520T) isolated from ginseng cultivation soil was characterized by using a polyphasic approach to clarify its taxonomic position. Strain Gsoil 520T was observed to grow optimally at 30 °C and pH 7.0 on Reasoner's 2A agar medium. The results of phylogenetic analysis, based on 16S rRNA gene sequence similarities, indicated that Gsoil 520T belongs to the genus Devosia of the family Hyphomicrobiaceae and was most closely related to Devosia epidermidihirudinis E84T (98.0 %), Devosia yakushimensis Yak96BT (97.7 %), Devosia neptuniae J1T (97.7 %) and Devosia chinhatensis IPL18T (96.8 %). The complete genome of strain Gsoil 520T is a presumptive circular chromosome of 4 480 314 base pairs having G+C content of 63.7 mol%. A total of 4 354 genes, 4 303 CDS and 43 rRNA genes were assigned a putative function. The major isoprenoid quinone was Q-10. The main polar lipids were phosphatidylglycerol, diphosphatidylglycerol and two unidentified aminolipids (AL1 and AL3). The predominant fatty acids of strain Gsoil 520T were C18 : 1ω7c 11-methyl, C16 : 0 and C18 : 1ω7c/C18 : 1ω6c (summed feature 8) supporting the affiliation of strain Gsoil 520T to the genus Devosia . The low values of DNA–DNA hybridization distinguished strain Gsoil 520T from the recognized species of the genus Devosia . Thus, the novel isolate represents a novel species of the genus Devosia , for which the name Devosia ginsengisoli sp. nov. is proposed, with the type strain Gsoil 520T (=KACC 19440T=LMG 30329T).

Devosia naphthalenivorans sp. nov., isolated from East Pacific Ocean sediment

A Gram-stain-negative bacterium, designated CM5-1^T, was isolated from a sediment sample collected from the East Pacific Ocean. 16S rRNA gene sequence analysis revealed that strain CM5-1^T belongs to the genus Devosia, with closely related type strains Devosia submarina KMM 9415^T (98.6 %), Devosia psychrophilaCr7-05^T (98.6 %) and Devosia psychrophilaE84^T (98.2 %). Up-to-date bacterial core gene set analysis revealed that strain CM5-1^T represents one independent lineage with D. submarina KMM 9415^T. The average nucleotide identity values of CM5-1^T with D. submarina KMM 9415^T and D. psychrophila Cr7-05^T are 80.1 and 77.9 %, respectively. In silico DNA-DNA hybridization values between strain CM5-1^T and D. submarina KMM 9415^T and D. psychrophila Cr7-05^T are 23.8 and 21.9 %, respectively. Strain CM5-1^T contains diphosphatidylglycerol, phosphatidylglycerol and glycolipid as major polar lipids. The sole isoprenoid quinone is ubiquinone-10, and C18 : 1ω7c and 11-methyl C18 : 1ω7c are the dominant cellular fatty acids. The G+C content of the genomic DNA is 61.4 mol%. Differential phylogenetic distinctiveness and chemotaxonomic differences, together with the phenotypic properties observed in this study, revealed that strain CM5-1^T could be differentiated from closely related species. Therefore, we propose strain CM5-1^T as a novel species of the genus Devosia, for which the name Devosia naphthalenivorans sp. nov. is suggested. The type strain is CM5-1^T (=JCM32509^T=CGMCC 1.13553^T).

Symbiont replacement between bacteria of different classes reveals additional layers of complexity in the evolution of symbiosis in the ciliate Euplotes

Symbiosis is a diverse and complex phenomenon requiring diverse model systems. The obligate relationship between a monophyletic group of Euplotes species ("clade B") and the betaproteobacteria Polynucleobacter and "Candidatus Protistobacter" is among the best-studied in ciliates, and provides a framework to investigate symbiont replacements. Several other Euplotes-bacteria relationships exist but are less understood, such as the co-dependent symbiosis between Euplotes magnicirratus (which belongs to "clade A") and the alphaproteobacterium "Candidatus Devosia euplotis". Here we describe a new Devosia inhabiting the cytoplasm of a strain of Euplotes harpa, a clade B species that usually depends on Polynucleobacter for survival. The novel bacterial species, "Candidatus Devosia symbiotica", is closely related to the symbiont of E. magnicirratus, casting a different light on the history of bacteria colonizing ciliates of this genus. The two Devosia species may have become symbionts independently or as the result of a symbiont exchange between hosts, in either case replacing a previous essential bacterium in E. harpa. Alternatively, both may be remnants of an ancient symbiotic relationship between Euplotes and Devosia, in which case Polynucleobacter and "Ca. Protistobacter" are recent invaders. Either way, symbiont replacement between bacteria belonging to different classes must be evoked to explain this fascinating system.