Ruijun Wang

Isolation and Complete Genome Sequence of Algibacter alginolytica sp. nov., a Novel Seaweed-Degrading Bacteroidetes Bacterium with Diverse Putative Polysaccharide Utilization Loci

ABSTRACT The members of the phylum Bacteroidetes are recognized as some of the most important specialists for the degradation of polysaccharides. However, in contrast to research on Bacteroidetes in the human gut, research on polysaccharide degradation by marine Bacteroidetes is still rare. The genus Algibacter belongs to the Flavobacteriaceae family of the Bacteroidetes, and most species in this genus are isolated from or near the habitat of algae, indicating a preference for the complex polysaccharides of algae. In this work, a novel brown-seaweed-degrading strain designated HZ22 was isolated from the surface of a brown seaweed (Laminaria japonica). On the basis of its physiological, chemotaxonomic, and genotypic characteristics, it is proposed that strain HZ22 represents a novel species in the genus Algibacter with the proposed name Algibacter alginolytica sp. nov. The genome of strain HZ22, the type strain of this species, harbors 3,371 coding sequences (CDSs) and 255 carbohydrate-active enzymes (CAZymes), including 104 glycoside hydrolases (GHs) and 18 polysaccharide lyases (PLs); this appears to be the highest proportion of CAZymes (∼7.5%) among the reported strains in the class Flavobacteria. Seventeen polysaccharide utilization loci (PUL) are predicted to be specific for marine polysaccharides, especially algal polysaccharides from red, green, and brown seaweeds. In particular, PUL N is predicted to be specific for alginate. Taking these findings together with the results of assays of crude alginate lyases, we prove that strain HZ22T can completely degrade alginate. This work reveals that strain HZ22T has good potential for the degradation of algal polysaccharides and that the structure and related mechanism of PUL in strain HZ22T are worth further research.

Hyphobacterium vulgare gen. nov., sp. nov., a novel alpha-proteobacterium isolated from seawater in the South China Sea.

A Gram-stain-negative, aerobic, non-spore-forming, non-motile, oval to rod-shaped, prosthecate bacterium, designated strain WM6T, was isolated from a seawater sample collected from the South China Sea at a depth of 150 m and subjected to a polyphasic taxonomic investigation. Cells of strain WM6T were approximately 0.5-0.6 µm in width and 0.8-1.2 µm in length, and colonies were smooth, circular, convex and whitish yellow. Strain WM6T was found to grow at 10-45 °C (optimum, 30 °C), at pH 6.5-9.0 (optimum, pH 7.5-8.5) and with 1-6 % (w/v) NaCl (optimum, 1-2 %). Chemotaxonomic analysis showed the predominant respiratory quinone and the major fatty acid of strains WM6T were ubiquinone-10 and C18 : 1ω7c, respectively. The polar lipids of strain WM6T were phosphatidylglycerol, glucuronopyranosyldiglyceride, monoglycosyldiglyceride, sulfo-quinovosyl diacylglycerol, seven unknown glycolipids and two unknown lipids. The DNA G+C content of strain WM6T was determined to be 59.8 mol% by HPLC. 16S rRNA gene sequence similarities showed that strain WM6T was related most closely to the genus Maricaulis with a similarity range from 92.3 to 93.8 %. Phylogenetic trees reconstructed with the neighbour-joining and maximum-likelihood methods using mega and maximum-likelihood methods using arb showed that strain WM6T constituted a separated branch in the family Hyphomonadaceae. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain WM6T is clearly distinct from any validly published genus. On the basis of these features, strain WM6T represents a novel species of a new genus with the name Hyphobacterium vulgare gen. nov., sp. nov. The type strain of Hyphobacterium vulgare is WM6T (=MCCC 1K03222T=KCTC 52487T).

Terasakiella brassicae sp. nov., isolated from the wastewater of a pickle-processing factory, and emended descriptions of Terasakiella pusilla and the genus Terasakiella.

A Gram-stain-negative, motile, polyhydroxybutyrate-accumulating, aerobic, S-shaped bacterium, designated B3T, was isolated from the wastewater of a pickle-processing factory. 16S rRNA gene sequence similarity analysis showed that it was most closely related to the type strain, Terasakiella pusilla (96.6% similarity). Strain B3T was able to grow at 4-40 °C (optimum 32-37 °C), pH 5.5-9.0 (optimum 6.5-7.5) and with 0.5-8% (w/v) NaCl present (optimum 1-2%, w/v). Chemotaxonomic analysis showed that the respiratory quinone was ubiquinone Q-10, the major fatty acids included C16:0, C18:1ω7c and C16:1ω7c and/or iso-C15:2-OH. The major polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, aminophospholipid and three uncharacterized phospholipids. The genomic DNA G+C content of strain B3T was 42.3 mol%. The DNA-DNA relatedness value between B3T and T. pusilla DSM 9263T was 23.9%. On the basis of the phenotypic, chemotaxonomic and genotypic characteristics of strain B3T, it represents a novel species of the genus Terasakiella, for which the name Terasakiella brassicae sp. nov. is proposed. The type strain is B3T (=KCTC 42652T=CGMCC 1.15254T). Emended descriptions of T. pusilla and the genus Terasakiella are also presented.

Roseivirga marina sp. nov., isolated from seawater.

Strain PSRT was isolated from seawater of the Pacific Ocean. Cells of the strain were Gram-stain-negative, strictly aerobic, rod-shaped and motile by gliding. Growth was observed at 4-40 °C (optimum 25-30 °C), at pH 6.0-9.5 (optimum pH 7.0-7.5) and with 0.5-8 % (w/v) NaCl (optimum 2-3 %). The major fatty acids were iso-C15 : 1 G (18.9 %), iso-C15 : 0 (26.3 %) and iso-C17 : 0 3-OH (17.9 %). The predominant isoprenoid quinone was MK-7, and the DNA G+C content was 49.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain PSRT was most closely related to Roseivirga spongicola UST030701-084T (96.9 % 16S rRNA gene sequence similarity), and they formed a distinct clade in neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees with significant bootstrap supports. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, strain PSRT represents a novel species of the genus Roseivirga, for which the name Roseivirga marina sp. nov. is proposed. The type strain is PSRT ( = MCCC 1K00459T = KCTC 42444T).

Growth responses to varying zinc activities in rice genotypes differing in Zn efficiency and Zn density.

ABSTRACT The relationship between tolerance to Zn-deficiency and Zn-dense in grain was examined. The results showed that the plant height and leaf growth rate (number) decreased more in the Zn-dense genotype (Biyuzaonuo) than in the Zn-efficient genotype (IR8192) when grown at pZn2+ ≥ 11.0. Shoot dry matter yield decreased about 6 times for the dense CV whereas only around 3 times for the efficient CV at Zn activities pZn2+ 9.7–11.4. Zinc uptake by the whole plant was greater in the Zn-dense genotype than in the Zn-efficient genotype, and the lowest in the Zn-inefficient genotype grown at pZn2+ ≥ 11.0. However, both the efficient and the dense cultivars showed higher Zn translocation efficiency at low Zn activity. These results indicate that Zn uptake by rice seedling and translocation might be more suitable than growth parameters for identifying Zn-efficient and Zn-dense genotype at seedling stage.

Mesorhizobium oceanicum sp. nov., isolated from deep seawater

A novel Gram-staining-negative, oval-shaped (0.4-0.6×0.8-1.0 µm), non-motile strain without flagella, designated B7T, was isolated from deep seawater in the South China Sea. Strain B7T was able to grow at 25-40 °C (optimum 35 °C), at pH 5.5-9.0 (optimum pH 7.0) and with 0-8 % (w/v) NaCl (optimum 3 %). Chemotaxonomic analysis showed that the predominant isoprenoid quinone was Q-10 and the dominant fatty acids were C19 : 0 cyclo 8c and summed feature 8 (C18 : 1ω7c/C18 : 1ω6c). The polar lipids of strain B7T were diphosphatidyglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unknown aminophospholipid, one unknown glycolipid and three unknown lipids. The DNA G+C content of the genomic DNA was 65.1 mol%. Phylogenetic analysis of 16S rRNA gene sequences showed that strain B7T belongs to the genus Mesorhizobium with similarities ranging from 96.2 to 97.5 %. Phylogenetic analyses of housekeeping genes recA, atpD and glnII indicated that strain B7T represented a distinct evolutionary lineage with the genus Mesorhizobium. OrthoANI values between strain B7T and related strains of the genus Mesorhizobium (<80 %) were lower than the threshold value of 95 % ANI relatedness for species demarcation. Therefore, strain B7T is concluded to represent a novel species of the genus Mesorhizobium, for which the name Mesorhizobium oceanicumsp. nov. is proposed. The type strain is B7T (=KCTC 42783T=MCCC 1K02305T).

Marinibaculum pumilum gen. nov., sp. nov., isolated from seawater

A Gram-stain-negative, facultatively anaerobic, motile and rod-shaped strain, designed H2T, was isolated from the Western Pacific Ocean, and subjected to a taxonomic investigation using a polyphasic approach. Strain H2T grew at 15-40 °C and pH 6.0-9.0 (optimum 37 °C and pH 6.5), and with 1-10 % (w/v) NaCl (optimum 2 %). The predominant respiratory quinone was ubiquinone-10 (Q-10) and the major fatty acids identified were C19 : 0 cyclo ω8c, C18 : 1ω7c, C18 : 0 and 11-methyl-C18 : 1ω7c. The polar lipids of strain H2T consisted of phosphatidylglycerol, one unknown phospholipid, one unknown glycolipid and three unidentified aminolipids. The DNA G+C content was 75.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain H2T formed a distinct clade belong to the family Rhodospirillaceae within the Alphaproteobacteria. On the basis of morphological, physiological and chemotaxonomic characteristics, together with the results of phylogenetic analysis, strain H2T represents a novel species in a new genus in the family Rhodospirillaceae, for which the name Marinibaculumpumilum gen. nov., sp. nov. is proposed. The type strain of the type species is H2T(=MCCC 1K02279T=KCTC 42964T).

Luteolibacter flavescens sp. nov., isolated from deep seawater

A novel Gram-stain-negative, rod-shaped, non-motile strain, designated GKXT, was isolated from deep seawater. Strain GKXT was able to grow at 20-35 °C (optimum, 25 °C), pH 5.5-9.5 (optimum, 7.5) and 0-4.0 % (w/v) NaCl (optimum, 1.0 %). The major fatty acids were C16 : 1ω9c (15.4 %), C16 : 0 (18.4 %), C14 : 0 (12.0 %), iso-C14 : 0 (30.1 %) and anteiso-C15 : 0 (5.7 %). Strain GKXT contained phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid as the main polar lipids. The only isoprenoid quinone was menaquinone-9. The diagnostic amino acids of the cell-wall peptidoglycan contained meso-diaminopimelic acid. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GKXT belonged to the genus Luteolibacter in the family Verrucomicrobiaceae. The 16S rRNA gene sequence of this strain showed 98.0, 93.5 and 93.3 % sequence similarity, respectively, with those of Luteolibacter arcticus MC 3726T, L.uteolibacter pohnpeiensisA4T-83T and L.uteolibacter cuticulihirudinis E100T. DNA-DNA hybridization value of strain GKXT with L. arcticus MC 3726T was 33.1 %. The G+C content of the genomic DNA was 59.5 mol%. On the basis of the genotypic, phenotypic, phylogenetic and chemotaxonomic characteristics, strain GKXT was proposed to represent a novel species of the genus Luteolibacter, named Luteolibacter flavescens sp. nov. (type strain GKXT=MCCC 1K03193T=KCTC 52361T).

Thalassobaculum fulvum sp. nov., isolated from deep seawater.

A novel Gram-stain-negative, rod-shaped (1.0-1.2×2.0-8.0 µm), non-motile without flagella strain, designated HSF7T, was isolated from deep seawater. Strain HSF7T was able to grow at 20-40 °C (optimum 35 °C), pH 5.5-9.0 (optimum pH 6.5) and 0-10 % (w/v) NaCl (optimum 2 %). The G+C content of the genomic DNA was 69 mol%. Bacteriochlorophyll a and poly-β-hydroxybutyrate (PHB) granules were not found. The major fatty acids were C18 : 1ω7c (69.3 %), C16 : 0 (9.1 %) and C19 : 0 cyclo ω8c (6.6 %). The polar lipids were phosphatidylglycerol, three unknown aminophospholipids, an unknown phospholipid, an unknown aminolipid and two unknown lipids. The only isoprenoid quinone was Q-10. 16S rRNA gene sequence analysis revealed that strain HSF7T was most closely related toThalassobaculum salexigens DSM 19539T, Thalassobaculum litoreum DSM 18839T, Nisaeadenitrificans DSM 18348T and Oceanibaculum indicum MCCC 1A02083Twith pairwise sequence similarities of 95.56 %, 95.21 %, 93.64 % and 92.65 %, respectively. On the basis of genotypic, phenotypic, phylogenetic and chemotaxonomic characteristics, strain HSF7T represents a novel species of the genus Thalassobaculum, or which the name Thalassobaculum fulvum sp. nov. is proposed. The type strain is HSF7T(=KCTC 42651T=MCCC 1K01158T).

Marinobacterium zhoushanense sp. nov., isolated from surface seawater.

A Gram-stain-negative, facultatively anaerobic bacterium, designated WM3T, was isolated from surface seawater collected from the East China Sea. Cells were catalase- and oxidase-positive, short rods and motile by means of a single polar flagellum. Growth occurred at 15-43 °C (optimum 37-40 C), pH 5.5-9.5 (optimum pH 6.5-7.5) and with 0.25-9.0 % (w/v) NaCl (optimum 1.0-1.5 %). Chemotaxonomic analysis showed that the respiratory quinone was ubiquinone-8, the major fatty acids included C16 : 0 (23.6 %), C18 : 1ω7c (26.2 %) and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH, 22.1 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain WM3T was most closely related to the genus Marinobacterium, sharing the highest 16S rRNA gene sequence similarity of 95.5 % with both Marinobacterium litorale KCTC 12756T and Marinobacterium mangrovicola DSM 27697T. The genomic DNA G+C content of the strain WM3T was 55.8 mol%. On the basis of phenotypic, chemotaxonomic and genotypic characteristics presented in this study, strain WM3T is suggested to represent a novel species of the genus Marinobacterium, for which the name Marinobacterium zhoushanense sp. nov. is proposed. The type strain is WM3T (=KCTC 42782T=CGMCC 1.15341T).