Complete genome sequence of Devosia beringensis S02T, a type strain with genes involved in deoxynivalenol degradation.

Members of the genus Devosia are known for their abilities to degrade deoxynivalenol (DON). The type strain Devosia beringensis S02T (= JCM 33772 = CCTCC AB 2019343) was isolated from sediment of the Bering Sea and identified in 2021. However, the genome sequence of D. beringensis S02T remains unclear, which complicates the exploration into the function and ecological role of this strain in marine sediment. The genome of D. beringensis S02T contained a 4,048,765 bp chromosome with a G + C content of 63.84 mol%. Potential genes involved in DON degradation were found in the genome. In addition, multiple genes involved in polysaccharide degradation, including agarose, chitin, carrageen, pectate, starch, and xylan, were also annotated in the genome. These findings indicated the potential of strain S02T to be used for DON degradation and its ecological function in the carbon cycle in marine sediment.

Devosia rhizoryzae sp. nov., and Devosia oryziradicis sp. nov., novel plant growth promoting members of the genus Devosia, isolated from the rhizosphere of rice plants.

Two novel Gram-negative, aerobic, asporogenous, motile, rod-shaped, orange and white pigmented, designated as LEGU1T and G19T, were isolated from the roots of rice plants, collected from Goyang, South Korea. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that they belonged to the genus Devosia and formed a different lineage and clusters with different members of the genus Devosia. These strains shared common chemotaxonomic features. In particular, they had Q-10 as the sole quinone, phosphatidylglycerol, diphosphatidylglycerol as the principal polar lipids and C16:0, C18:1ω7c 11-methyl and summed feature 8 (comprising C18:1ω7c/C18:1ω6c) as the main fatty acids. The draft genome sequences of strains LEGU1T and G19T were 3,524,978 and 3,495,520 bp in size, respectively. Their average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were 72.8-81.9% and 18.7-25.1%, respectively, with each other and type strains of related species belonging to the genus Devosia, suggesting that these two strains represent novel species. The G + C content of strains LEGU1T and G19T were 62.1 and 63.8%, respectively. Of the two strains, only LEGU1T produced carotenoid and flexirubin-type pigment. Both strains produced siderophore and indole acetic acid (IAA) in the presence of L-tryptophan. Siderophore biosynthesis genes, auxin responsive genes and tryptophan biosynthesis genes were present in their genomes. The present study aimed to determine the detailed taxonomic positions of the strains using the modern polyphasic approach. Based on the results of polyphasic analysis, these strains are suggested to be two novel bacterial species within the genus Devosia. The proposed names are D. rhizoryzae sp. nov., and Devosia oryziradicis sp. nov., respectively. The plant growth promoting effects of these strains suggest that they can be exploited to improve rice crop productivity. The type strain of D. rhizoryzae is LEGU1T (KCTC 82712T = NBRC 114485T) and D. oryziradicis is G19T (KCTC 82688T = NBRC 114842T).

Genomic diversity, life strategies and ecology of marine HTVC010P-type pelagiphages.

SAR11 bacteria dominate ocean surface bacterioplankton communities, and play an important role in marine carbon and nutrient cycling. The biology and ecology of SAR11 are impacted by SAR11 phages (pelagiphages) that are highly diverse and abundant in the ocean. Among the currently known pelagiphages, HTVC010P represents an extremely abundant but under-studied phage group in the ocean. In this study, we have isolated seven new HTVC010P-type pelagiphages, and recovered 77 nearly full-length HTVC010P-type metagenomic viral genomes from marine metagenomes. Comparative genomic and phylogenomic analyses showed that HTVC010P-type pelagiphages display genome synteny and can be clustered into two major subgroups, with subgroup I consisting of strictly lytic phages and subgroup II mostly consisting of phages with potential lysogenic life cycles. All but one member of the subgroup II contain an integrase gene. Site-specific integration of subgroup II HTVC010P-type pelagiphage was either verified experimentally or identified by in silico genomic sequence analyses, which revealed that various SAR11 tRNA genes can serve as the integration sites of HTVC010P-type pelagiphages. Moreover, HTVC010P-type pelagiphage integration was confirmed by the detection of several Global Ocean Survey (GOS) fragments that contain hybrid phage-host integration sites. Metagenomic recruitment analysis revealed that these HTVC010P-type phages were globally distributed and most lytic subgroup I members exhibited higher relative abundance. Altogether, this study significantly expands our knowledge about the genetic diversity, life strategies and ecology of HTVC010P-type pelagiphages.

Devosia sediminis sp. nov., isolated from subterranean sediment.

A novel Gram-negative, cream-colored, rod-shaped, aerobic, non-motile bacterium, designated MSA67T, was isolated from a subterranean sediment sample of the Mohe Basin in Northeast China. Strain MSA67T was detected to grow at 4-40 °C (optimum 28-30 °C), pH 5.0-10.0 (optimum, pH 7.0) and in 0.0-8.0% (w/v) NaCl (optimum 2.0-3.0%). Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain MSA67T was a member of the genus Devosia, with the highest similarity with D. riboflavina IFO13584T (98.0%) and D. chinhatensis IPL18T (97.0%). The major cellular fatty acids are C16:0, C18:1ω7c 11-methyl and C18:1ω6c and/or C18:1ω7c. The major polar lipids are diphosphatidylglycerol, phosphatidylglycerol, glycolipids and three unidentified phospholipids. The major respiratory quinone is ubiquinone 10 (Q-10). The genomic size of strain MSA67T is 4.1 MB and DNA G + C content is 63.6%. Based on genotypic, phenotypic and phylogenetic results, strain MSA67T is concluded to represent a novel species of the genus Devosia, for which the name Devosia sediminis sp. nov. is proposed. The type strain is MSA67T (= CGMCC 1.18467T = KCTC 82192T).

Pelagibacterium limicola sp. nov., isolated from a soda alkali-saline soil.

A Gram-staining negative, motile, non-spore-forming, rod-shaped bacterium, designated NAJP-14T, was isolated from the alkali-saline soil in Heilongjiang, Northeast China. Phylogenetic analysis based on 16S rRNA gene sequencing illustrated that strain NAJP-14T was a member of the genus Pelagibacterium, and shared 94.6-96.6% sequence identities to species from the genus Pelagibacterium. Strain NAJP-14T grew at 20-45 °C (optimum, 30 °C), pH 7.0-10.0 (optimum, pH 8.0) and in the presence of up to 5% w/v NaCl. The menaquinone was determined to be Q (10). The major fatty acids were identified as C18:1w6c (38.7%), C16:0 (16.2%) and C19:0 cyclo w8c (13.9%). The G + C content of the genomic DNA was 61.2%. Out of the 3442 predicted genes, 3391 were protein-coding genes and 51 were ncRNA. Digital DNA-DNA hybridization (dDDH) estimation and average nucleotide identity (ANI) of the strain NAJP-14T and the type strains of related species in the same family ranged between 17.9 and 21.8% and between 61.4 and 78.7%, respectively. Based on these data, it is concluded that strain NAJP-14T possesses sufficient characteristics to differentiate it from all recognized Pelagibacterium species, and should be considered as a novel species for which the name Pelagibacterium limicola sp. nov. is proposed. The type strain is NAJP-14T (= CGMCC 1.16631T, = JCM 33746T).

An uncharacterized clade in the DMSO reductase family of molybdenum oxidoreductases is a new type of chlorate reductase.

The dimethylsulfoxide (DMSO) reductase family of enzymes has many subfamilies catalysing unique biogeochemical reactions. It also has many uncharacterized subfamilies. Comparative genomics predicted one such subfamily to participate in a key step of the chlorine cycle because of a conserved genetic association with chlorite dismutase, implying they produce chlorite through chlorate or perchlorate reduction. We determined the activity of the uncharacterized enzyme by comparing strains in the phototrophic genus Rhodoplanes that encode either a typical perchlorate reductase or the uncharacterized enzyme. Rpl. piscinae and Rpl. elegans, which encode perchlorate reductase, grew by using perchlorate as an electron acceptor. In contrast, Rpl. roseus, which encodes the uncharacterized enzyme, grew by chlorate reduction but not by perchlorate reduction. This is the first report of perchlorate and chlorate being used as respiratory electron acceptors by phototrophs. When both chlorate and perchlorate were present, Rpl. roseus consumed only chlorate. Highly concentrated Rpl. roseus cells showed some perchlorate consumption, but chlorate consumption occurred at a 10-fold higher rate. Together, these genomic and physiological data define a new group of chlorate reductases. Some organisms encode both this chlorate reductase and a perchlorate reductase, raising new questions about the physiology and evolution of chlorine oxyanion respiration.

Enzymatic degradation of deoxynivalenol by a novel bacterium, Pelagibacterium halotolerans ANSP101.

Deoxynivalenol (DON), a toxic secondary metabolite produced by Fusarium species that mainly infests cereals such as wheat and corn, threatens human and livestock health. The present study describes the characterization of a novel bacterial strain, Pelagibacterium halotolerans ANSP101 which is capable of transforming DON to less-toxic product 3-keto-deoxynivalenol by the oxidation of the C3 hydroxyl group. Strain ANSP101 was isolated from a seawater sample from a depth of 55 m in Chinese Bohai sea. The strain was identified as Pelagibacterium halotolerans by morphology characterization and 16S rDNA gene sequencing. The DON degrading activity of strain ANSP101 was predominantly attributed to the bacterial cell lysate. Besides, the cell lysate was sensitive to sodium dodecyl sulfate, heat, and proteinase K treatment, indicating that the intracellular proteins or enzymes are responsible for the DON degradation. The optimal temperature and pH for the maximal degradation of DON were 40 °C and pH 8.0 by the cell lysate. These results provide the potential use of P. halotolerans ANSP101 as a detoxification agent for DON decontamination in cereals and feed.

Defining the Environmental Adaptations of Genus Devosia: Insights into its Expansive Short Peptide Transport System and Positively Selected Genes.

Devosia are well known for their dominance in soil habitats contaminated with various toxins and are best characterized for their bioremediation potential. In this study, we compared the genomes of 27 strains of Devosia with aim to understand their metabolic abilities. The analysis revealed their adaptive gene repertoire which was bared from 52% unique pan-gene content. A striking feature of all genomes was the abundance of oligo- and di-peptide permeases (oppABCDF and dppABCDF) with each genome harboring an average of 60.7 ± 19.1 and 36.5 ± 10.6 operon associated genes respectively. Apart from their primary role in nutrition, these permeases may help Devosia to sense environmental signals and in chemotaxis at stressed habitats. Through sequence similarity network analyses, we identified 29 Opp and 19 Dpp sequences that shared very little homology with any other sequence suggesting an expansive short peptidic transport system within Devosia. The substrate determining components of these permeases viz. OppA and DppA further displayed a large diversity that separated into 12 and 9 homologous clusters respectively in addition to large number of isolated nodes. We also dissected the genome scale positive evolution and found genes associated with growth (exopolyphosphatase, HesB_IscA_SufA family protein), detoxification (moeB, nifU-like domain protein, alpha/beta hydrolase), chemotaxis (cheB, luxR) and stress response (phoQ, uspA, luxR, sufE) were positively selected. The study highlights the genomic plasticity of the Devosia spp. for conferring adaptation, bioremediation and the potential to utilize a wide range of substrates. The widespread toxin-antitoxin loci and 'open' state of the pangenome provided evidence of plastic genomes and a much larger genetic repertoire of the genus which is yet uncovered.

Ecogenomics of the SAR11 clade.

Members of the SAR11 clade, despite their high abundance, are often poorly represented by metagenome-assembled genomes. This fact has hampered our knowledge about their ecology and genetic diversity. Here we examined 175 SAR11 genomes, including 47 new single-amplified genomes. The presence of the first genomes associated with subclade IV suggests that, in the same way as subclade V, they might be outside the proposed Pelagibacterales order. An expanded phylogenomic classification together with patterns of metagenomic recruitment at a global scale have allowed us to define new ecogenomic units of classification (genomospecies), appearing at different, and sometimes restricted, metagenomic data sets. We detected greater microdiversity across the water column at a single location than in samples collected from similar depth across the global ocean, suggesting little influence of biogeography. In addition, pangenome analysis revealed that the flexible genome was essential to shape genomospecies distribution. In one genomospecies preferentially found within the Mediterranean, a set of genes involved in phosphonate utilization was detected. While another, with a more cosmopolitan distribution, was unique in having an aerobic purine degradation pathway. Together, these results provide a glimpse of the enormous genomic diversity within this clade at a finer resolution than the currently defined clades.

Blastochloris tepida, sp. nov., a thermophilic species of the bacteriochlorophyll b-containing genus Blastochloris.

A new taxon is created for the thermophilic purple nonsulfur bacterium previously designated as Rhodopseudomonas strain GI. Strain GI was isolated from a New Mexico (USA) hot spring microbial mat and grows optimally above 40 °C and to a maximum of 47 °C. Strain GI is a bacteriochlorophyll b-containing species of purple nonsulfur bacteria and displays a budding morphology, typical of species of the genus Blastochloris. Although resembling the species Blc. viridis in many respects, the absorption spectrum, carotenoid content, and lipid fatty acid profile of strain GI is distinct from that of Blc. viridis strain DSM133T and other recognized Blastochloris species. Strain GI forms its own subclade within the Blastochloris clade of purple nonsulfur bacteria based on comparative 16S rRNA gene sequences, and its genome is significantly larger than that of strain DSM133T; average nucleotide identity between the genomes of Blc. viridis and strain GI was below 85%. Moreover, concatenated sequence analyses of PufLM and DnaK clearly showed strain GI to be distinct from both Blc. viridis and Blc. sulfoviridis. Because of its unique assortment of properties, it is proposed to classify strain GI as a new species of the genus Blastochloris, as Blc. tepida, sp.n., with strain GIT designated as the type strain (= ATCC TSD-138 = DSM 106918).

Biodegradation of deoxynivalenol and its derivatives by Devosia insulae A16.

Deoxynivalenol (DON), a notorious mycotoxin mainly found in Fusarium-contaminated crops, causes great loss in livestock farming and severe safety risks to human health. Here we report the isolation of a Gram-negative bacterial strain with effective biodegrading abilities on DON and its derivatives including 3-acetyl-DON and 15-acetyl-DON. The strain was identified as Devosia insulae A16 on the basis of morphological and physiological characteristics and 16S rRNA-based phylogenetic analysis. D. insulae A16 was able to degrade 88% of 20 mg/l DON within 48 h under aerobic conditions at 35 °C and neutral pH. The major degradation product of DON and its derivatives was 3-keto-DON by the oxidation of the hydroxyl group at C-3. Both 3-acetyl-DON and 15-acetyl-DON underwent a deacetylation reaction to generate DON prior to the degradation to 3-keto-DON. The results provide the potential use of D. insulae A16 as a biodegradation agent to control DON contamination in cereals.

Pelagibacterium montanilacus sp. nov., an alkaliphilic bacterium isolated from Lake Cuochuolong on the Tibetan Plateau.

A Gram-stain negative, alkaliphilic and halotolerant bacterium, designated CCL18T, was isolated from Lake Cuochuolong on the Tibetan Plateau. The strain was aerobic, short rod-shaped, catalase- and oxidase-positive, and motile by means of several polar flagella. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain CCL18T belongs to the genus Pelagibacterium, with its two closest neighbours being Pelagibacterium halotolerans B2T (96.6 %, 16S rRNA gene sequence similarity) and Pelagibacterium luteolum 1_C16_27T (96.1 %). The predominant respiratory quinone of strain CCL18T was Q-10, with Q-9 as a minor component. The major fatty acids were C18 : 1ω6c/C18 : 1ω7c (60.4 %), C19 : 0cyclo ω8c (8.1 %) and C18 : 0 (6.8 %). The polar lipids included phosphatidylglycerol, diphosphatidylglycerol, seven kinds of unidentified lipids and three kinds of glycolipids. The DNA G+C content was 60.1 mol%. DNA-DNA hybridization showed 35.2 % relatedness between strain CCL18T and P. halotolerans B2T and 24.6 % relatedness to P. luteolum 1_C16_27T. Based on phylogenetic analysis, DNA-DNA hybridization and a range of physiological and biochemical characteristics, strain CCL18T was clearly distinguishable from the other strains of the genus Pelagibacterium. It was evident that strain CCL18T could be classified as a novel species of the genus Pelagibacterium, for which the name Pelagibacterium montanilacus sp. nov. is proposed. The type strain is CCL18T (=CGMCC 1.16231T=KCTC 62030T).

Massive over-representation of solute-binding proteins (SBPs) from the tripartite tricarboxylate transporter (TTT) family in the genome of the α-proteobacterium Rhodoplanes sp. Z2-YC6860.

Lineage-specific expansion (LSE) of protein families is a widespread phenomenon in many eukaryotic genomes, but is generally more limited in bacterial genomes. Here, we report the presence of 434 genes encoding solute-binding proteins (SBPs) from the tripartite tricarboxylate transporter (TTT) family, within the 8.2 Mb genome of the α-proteobacterium Rhodoplanes sp. Z2-YC6860, a gene family over-representation of unprecedented abundance in prokaryotes. Representing over 6 % of the total number of coding sequences, the SBP genes are distributed across the whole genome but are found rarely in low-GC islands, where the gene density for this family is much lower. This observation, and the much higher sequence identity between the 434 Rhodoplanes TTT SBPs compared with the average identity between homologues from different species, is indicative of a key role for LSE in the expansion. The TTT SBP genes were found in the vicinity of genes encoding membrane components of transport systems from different families, as well as regulatory proteins such as histidine-kinases and transcription factors, indicating a broad range of functions around the sensing, response and transport of organic compounds. A smaller expansion of TTT SBPs is known in some species of the ß-proteobacteria Bordetella and we observed similar expansions in other ß-proteobacterial lineages, including members of the genus Comamonas and the industrial biotechnology organism Cupriavidus necator, indicating that strong environmental selection can drive SBP duplication and specialisation from multiple evolutionary starting points.

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.

Limoniibacter endophyticus gen. nov., sp. nov., an alphaproteobacterium isolated from the roots of Limonium otolepis.

A Gram-negative bacterium, designated as strain YIM 690229T, was isolated from the roots of Limonium otolepis. The strain was able to grow at 10-40 °C (optimum, 28-37 °C), pH 6.0-8.0 (optimum, 7.0) and in the presence of up to 7% NaCl (w/v) (optimum, up to 2.5%). Comparative 16S rRNA gene sequence analysis revealed that strain YIM 690229T shared less than 93.9% sequence similarities with members within the order Rhizobiales, and was remotely related to members of the family Hyphomicrobiaceae. Strain YIM 690229T was characterized by the presence of Q-10 as the predominant respiratory lipoquinone. The major fatty acids (> 10%) detected were C18:1 ω7c, C16:0, anteiso-C15:0 and summed feature 4 (iso-C17:1 I and/or anteiso-C17:1 B). The polar lipids consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmethylethanoamine and two unidentified lipids. The genomic DNA G + C content was 57.2 mol%. Data from this polyphasic taxonomy study suggested that strain YIM 690229T should be classified as a new species of a new genus within the family Hyphomicrobiaceae for which the name Limoniibacter endophyticus gen. nov., sp. nov., is proposed. The type species of the genus Limoniibacter gen. nov. is Limoniibacter endophyticus. The type strain of the species Limoniibacter endophyticus sp. nov. is YIM 690229T (= KCTC 42097T = JCM 30141T = CCTCC AB 2014130T = CGMCC 1.12906T).

The enzymatic detoxification of the mycotoxin deoxynivalenol: identification of DepA from the DON epimerization pathway.

The biological detoxification of mycotoxins, including deoxynivalenol (DON), represents a very promising approach to address the challenging problem of cereal grain contamination. The recent discovery of Devosia mutans 17-2-E-8 (Devosia spp. 17-2-E-8), a bacterial isolate capable of transforming DON to the non-toxic stereoisomer 3-epi-deoxynivalenol, along with earlier reports of bacterial species capable of oxidizing DON to 3-keto-DON, has generated interest in the possible mechanism and enzyme(s) involved. An understanding of these details could pave the way for novel strategies to manage this widely present toxin. It was previously shown that DON epimerization proceeds through a two-step biocatalysis. Significantly, this report describes the identification of the first enzymatic step in this pathway. The enzyme, a dehydrogenase responsible for the selective oxidation of DON at the C3 position, was shown to readily convert DON to 3-keto-DON, a less toxic intermediate in the DON epimerization pathway. Furthermore, this study provides insights into the PQQ dependence of the enzyme. This enzyme may be part of a feasible strategy for DON mitigation within the near future.

Characterization of thermotolerant phototrophic bacteria, Rhodoplanes tepidicaeni sp. nov. and Rhodoplanes azumiensis sp. nov., isolated from a geothermal spring.

Two strains of thermotolerant phototrophic alphaproteobacteria, designated strains TUT3542T and TUT3581T, were isolated from sediment mud and cyanobacterial mats in a geothermal spring in Japan, respectively, and taxonomically characterized. Both the strains were budding motile rods and were able to grow at 45 °C. Phototrophically grown cells of strains TUT3542T and TUT3581T produced pink and brownish red cultures, respectively, and showed in vivo absorption maxima at 800, 858-859 and 892-895 nm in the near infrared region, indicating the presence of a core reaction centre and peripheral pigment complexes with bacteriochlorophyll a. The intracytoplasmic membrane system was of the lamellar type parallel to the cytoplasmic membrane. 16S rRNA gene sequence comparisons showed that strains TUT3542T and TUT3581T had the highest similarity level to Rhodoplanes oryazae NBRC 109406T (99.6 %) and Rhodoplaneselegans AS130T (99.3 %), respectively. Genomic DNA-DNA reassociation studies revealed that strains TUT3542T and TUT3581T had hybridization levels of less than 62 and 56 % to the type strains of all established species of the genus Rhodoplanes, respectively. The G+C contents of genomic DNA were 67.7 mol% for strain TUT3542T and 70.4 mol% for strain TUT3581T. Results of phenotypic studies showed that the two novel strains could be differentiated from any of the previously described Rhodoplanes species. Thus, the author proposes the names Rhodoplanes tepidicaeni sp. nov. for strain TUT3542T and Rhodoplanes azumiensis sp. nov. for strain TUT3581T. The type strain of Rhodoplanes tepidicaeni is TUT3542T (=KCTC 15602T=NBRC 112815T) and the type strain of Rhodoplanes azumiensis is TUT3581T (=KCTC 15603T=NBRC 112816T).

Pelagibacterium lentulum sp. nov., a marine bacterium from the culture broth of Picochlorum sp. 122.

A Gram-stain-negative, motile, non-spore-forming, rod-shaped bacterium, designated strain B2T, was isolated from the culture broth of a marine microalga, Picochlorum sp. 122. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain B2T forms a robust cluster with members of the genus Pelagibacterium, and shares the highest sequence similarity of 96.80 % with Pelagibacterium halotolerans CGMCC 1.7692T. Optimal growth of strain B2T was observed at 33 °C, at pH 8 and in the presence of 1 % (w/v) NaCl. The predominant ubiquinone of strain B2T was Q-10, and the G+C content of the genomic DNA was 58.6 mol%. The major fatty acid profile comprised C18 : 1ω7c/ω6c, C19 : 0 cyclo ω8c and C16 : 0. The major polar lipids of strain B2T were diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and seven unidentified lipids. Comprehensive analyses based on a polyphasic characterization of strain B2T indicated that it represents a novel species of the genus Pelagibacterium, for which the name Pelagibacterium lentulum sp. nov. is proposed. The type strain is B2T (=MCCC 1K03218T=CGMCC 1.15896T=KCTC 52551T).

Devosia nitraria sp. nov., a novel species isolated from the roots of Nitraria sibirica in China.

An aerobic, Gram-stain negative, short rod-shaped and motile strain, 36-5-1T, was isolated from the roots of Nitraria sibirica in Zhangye city, Gansu province, north-west of China. Phylogenetic analysis based on the 16S rRNA gene sequence and two housekeeping genes (glnA and atpD) indicated that the strain represents a novel species closely related to the Devosia, Rhizobium and Devosia genera with 98.3, 96.2 and 91.1% similarities, respectively. The strain 36-5-1T contained Q-10 as the predominant ubiquinone and 16:0 (36.8%) as the major fatty acid; a large amount of unidentified glycolipid, diphosphatidylglycerol, phosphatidylglycerol and a small amount of unidentified polar lipids were present as polar lipids. In addition, the G+C content of the genomic DNA was 61.7 mol% and the DNA-DNA hybridization with type strains Devosia geojensis BD-c194T and Devosia pacifica NH131T 44.1 ± 1.1 and 40.2 ± 1.7, respectively. Based on chemotaxonomic data and molecular properties, strain 36-5-1T represents a novel species within the genus Devosia, for which the name Devosia nitraria sp. nov. is proposed. The type strain is 36-5-1T (=CGMCC1.15704T=NBRC112416T).

Proposal of Rhodoplanes tepidamans sp. nov. to accommodate the thermotolerant phototrophic bacterium previously referred to as 'Rhodoplanes (Rhodopseudomonas) cryptolactis'.

Previously we proposed the reclassification of a thermotolerant phototrophic bacterium, 'Rhodopseudomonas cryptolactis' Stadtwald-Demchick et al. 1990, as 'Rhodoplanes cryptolactis' nom. rev., comb. nov. with strain DSM 9987T (ATCC 49414T) as the type strain. However, while both the names 'Rhodopseudomonas cryptolactis' and 'Rhodoplanes cryptolactis' have not been validated, strain ATCC 49414T is no longer available from the culture collection. This situation indicates that the taxonomic status of the bacterium with both the names to be validated has been lost. In this study, we re-examined the taxonomic characteristics of strain DSM 9987T (TUT3520T as our own collection number) compared with those of six species of the genus Rhodoplanes with validly published names. The results of 16S rRNA gene sequence comparisons indicated that TUT3520T had a 99.0 % level of similarity to the type strains of Rhodoplanes oryzae and Rhodoplanes elegans as its closest relatives and 98.9-96.2 % similarities to other species of the genus Rhodoplanes. Genomic DNA-DNA similarities between TUT3520T and the type strains of the species of the genus Rhodoplanes were less than 50 %. Results of phenotypic testing indicated that TUT3520T could be differentiated from any species of the genus Rhodoplanes by a combination of in vivo absorption spectra, growth temperature, vitamin requirements, carbon nutrition and some other characteristics. Thus, we propose Rhodoplanes tepidamans sp. nov. to accommodate the bacterium previously referred to as 'Rhodoplanes (Rhodopseudomonas) cryptolactis'. The type strain is strain TUT3520T (=DSM 9987T=NBRC 104267T).