Leonid N. Ten

Spirosoma luteolum sp. nov. isolated from water

A novel Gram-negative and rod-shaped bacterial strain, designated as 16F6ET, was isolated from a water sample. Cells were yellowish in color and catalase- and oxidase-positive. The strain grew at 10–37°C (optimum at 25°C) but not at 4 and 42°C, and pH 5–7 (optimum at pH 7). It showed moderate resistance to gamma-ray irradiation. Comparative phylogenetic analysis showed that strain 16F6ET belonged to the family Cytophagaceae of the class Cytophagia. Furthermore, this isolate showed relatively low 16S rRNA gene sequence similarities (90.7–93.1%) to the members of the genus Spirosoma. The major fatty acids were summed feature 3 (C16:1ω7c/C16:1ω6c), C16:1ω5c, C16:0 N alcohol, and C16:0. The polar lipid profile indicated presence of phosphatidylethanolamine, unknown aminophospholipids, an unknown amino lipid, unknown phospholipids, and unknown polar lipids. The predominant isoprenoid quinone was MK-7. The genomic DNA G+C content of strain 16F6ET was 56.5 mol%. Phenotypic, phylogenetic, and chemotaxonomic properties indicated that isolate 16F6ET represents a novel species within the genus Spirosoma, for which the name Spirosoma luteolum sp. nov. is proposed. The type strain is 16F6ET (=KCTC 52199T =JCM 31411T).

Hymenobacter daeguensis sp. nov. isolated from river water

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterial strain, designated 16F3Y-2T, was isolated from the Han River, South Korea, and was characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain 16F3Y-2T belonged to the family Cytophagaceae in the phylum Bacteroidetes and was most closely related to ‘Hymenobacter terrae’ DG7A (98.01%), H. soli PB17T (97.26%), H. glaciei VUG-A130T (96.78%), H. antarcticus VUG-A42aaT (96.72%), H. ruber PB156T (96.61%), and H. saemangeumensis GSR0100T (95.77%). The G+C content of the genomic DNA of strain 16F3Y-2T was 62.9 mol%. The isolate contained MK-7 as the predominant respiratory quinone, and summed feature 3 (C16:1ω7c/C16:1ω6c; 35.5%), C15:0 iso (16.9%), C16:1ω5c (10.9%), and C15:0 anteiso (9.9%) as major fatty acids. The major polar lipid was phosphatidylethanolamine. Phenotypic and chemotaxonomic data supported the affiliation of strain 16F3Y-2T with the genus Hymenobacter. However, strain 16F3Y-2T exhibited relatively low levels of DNA-DNA relatedness with ‘H. terrae’ KCTC 32554 (44.1%) and H. soli KCTC 12607T (24.3%), clearly indicating that the isolate constitutes a new genospecies. Strain 16F3Y-2T could be differentiated from its phylogenetic neighbors on the basis of several phenotypic, genotypic, and chemotaxonomic features. Therefore, strain 16F3Y-2T represents a novel species in the genus Hymenobacter, for which the name Hymenobacter daeguensis sp. nov. is proposed. The type strain is 16F3Y-2T (=KCTC 52537T =JCM 31654T).

Hymenobacter aquaticus sp. nov., a radiation-resistant bacterium isolated from a river

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterial strain, designated 16F3PT, was isolated from the Han River, South Korea, and characterized taxonomically using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed 16F3PT to be within the genus Hymenobacter, and most closely related to Hymenobacterchitinivorans Txc1T (98.62 %) and Hymenobacterelongatus VUG-A112T (98.46 %). The phylogenetic distance from other species of the genus Hymenobacter with validly published names was greater than 4 % (i.e. sequence similarity was less than 96.0 %). Chemotaxonomic data also supported the classification of strain 16F3PT within the genus Hymenobacter. C16 : 0 (19.8 %), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 15.4 %) and iso-C15 : 0 (13.0 %) were the major fatty acids, MK-7 was the predominant respiratory quinone, and phosphatidylethanolamine was the major polar lipid. The G+C content of the genomic DNA of strain 16F3PT was 61.9 mol%. DNA-DNA hybridization experiments showed that the values for DNA-DNA relatedness between strain 16F3PT and the phylogenetically closest neighbours were below 19 %. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain 16F3PT represents a novel species of the genus Hymenobacter, for which the name Hymenobacter aquaticus sp. nov. is proposed. The type strain is 16F3PT (=KCTC 52194T=JCM 31653T).

Hymenobacter seoulensis sp. nov., isolated from river water

A Gram-stain-negative, aerobic, rod-shaped, non-motile and pink-pigmented bacterial strain, designated 16F7GT, was isolated from river water. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 16F7GT belongs to the genus Hymenobacter. The 16S rRNA gene sequence similarity to members of the genus Hymenobacter ranged from 90.5 to 97.4 %, and the most closely related strains were Hymenobacter rigui WPCB131T (97.4 %) and Hymenobacter xinjiangensis X2-1gT (97.3 %). Strain 16F7GT had <70 % DNA-DNA relatedness with H. rigui (32.8±7.8 %) and H. xinjiangensis (30.2±6.2 %), indicating that it represents a novel genospecies. Cells were catalase- and oxidase-positive. The genomic DNA G+C content was 56.6 mol%. The major fatty acids were summed feature 4 (C17 : 1iso I/C17 : 1 anteiso B; 19.8 %), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 18.4 %), C15 : 0 iso (17.0 %), C16 : 1ω5c (11.8 %) and C15 : 0 anteiso (9.8 %). The major polar lipid was phosphatidylethanolamine and the predominant respiratory quinone was menaquinone 7 (MK-7). Based on the phylogenetic, phenotypic, genotypic and chemotaxonomic analyses, it is concluded that strain 16F7GT represents a novel species within the genus Hymenobacter, for which the name Hymenobacter seoulensis sp. nov. is proposed. The type strain is 16F7GT (=KCTC 52197T=JCM 31655T).

New Recorded Species in Three Genera of the Sordariomycetes in Korea

Abstract In an ongoing survey of Korean indigenous fungi, three fungal strains belonging to the Sordariomycetes were isolated from soil samples. These strains were designated KNU16-001, KNU16-002, and KNU16-009, and identified as Ambrosiella grosmanniae, Acremonium sclerotigenum, and Trichocladium asperum, respectively, based on morphological characterization and phylogenetic analysis using internal transcribed spacer region sequences of ribosomal DNA. This is the first report of these species in Korea.

Larkinella roseus sp. nov., a species of the family Cytophagaceae isolated from beach soil

The taxonomic position of bacterial strain, designated 15J16-1T3AT, recovered from a soil sample was established using a polyphasic approach. Phylogenic analysis based on the 16S rRNA gene sequence showed that strain 15J16-1T3AT belonged to the family Cytophagaceae, phylum Bacteroidetes, and was most closely related to ‘Larkinella harenae’ 15J9-9 (95.9% similarity), Larkinella ripae 15J11-11T (95.6%), Larkinella bovis M2TB15T (94.7%), Larkinella arboricola Z0532T (93.9%), and Larkinella insperata LMG 22510T (93.5%). Cells were rod-shaped, Gram-stain-negative, aerobic, and nonmotile. The isolate grew on NA, R2A, TSA, but not on LB agar. The strain was able to grow at temperature range from 10°C to 30°C with an optimum at 25°C and pH 6–8. Menaquinone MK-7 was the predominant respiratory quinone. The major cellular fatty acids comprised C16:1ω5c (48.6%) and C15:0 iso (24.1%). Phosphatidylethanolamine, phosphatidylserine, and an unidentified lipid were the major polar lipids. The G + C content of the genomic DNA was 49.5 mol%. Strain 15J16-1T3AT could be distinguished from its closest phylogenetic neighbors based on its phenotypic, genotypic, and chemotaxonomic features. Therefore, the isolate is considered to represent a novel species in the genus Larkinella, for which the name Larkinella roseus sp. nov. is proposed. The type strain is 15J16-1T3AT (= KCTC 52004T = JCM 31991T).

Spirosoma daeguensis sp. nov., isolated from beach soil

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterium, designated 15J9-6T, was isolated from beach soil on Jeju Island, South Korea. Strain 15J9-6T, grew at 10–30°C (optimum growth at 25°C) and pH 7–8 (optimum growth at pH 7) on R2A, NA, and TSA agar. Phylogenetically, the strain was closely related to members of the genus Spirosoma (92.3–90.1% 16S rRNA gene sequence similarities) and showed highest sequence similarity to Spirosoma panaciterrae DSM 21099T (92.3%). The G+C content of the genomic DNA of strain 15J9-6T was 45.7 mol%. The strain contained phosphatidylethanolamine, two unidentified aminophospholipids, an unidentified phospholipid, and an unidentified lipid as the major polar lipids; menaquinone MK-7 as the predominant respiratory quinone and summed feature 3 (C16:1ω6c/C16:1ω7c; 30.1%), C16:1ω5c (23.1%), iso C15:0 (13.3%), and C16:0 (8.4%) as the major fatty acids which supported the affiliation of strain 15J9-6T to the genus Spirosoma. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 15J9-6T from recognized Spirosoma species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain 15J9-6T represents a novel species of the genus Spirosoma, for which the name Spirosoma daeguensis sp. nov. is proposed. The type strain is 15J9-6T (=KCTC 52036T =JCM 31995T)

Adhaeribacter terrae sp. nov., a novel bacterium isolated from soil

Strain HY02T was isolated from a soil sample collected at Namyangju-si, Gyeonggi-do, Republic of Korea. Cells of this strain were observed to be Gram-stain-negative, short and rod-shaped. Colonies were red in colour. A 16S rRNA gene sequence analysis identified this strain as a member of the genus Adhaeribacter in the family Cytophagaceae, with the highest level of 16S rRNA gene sequence similarity to Adhaeribacter terreus DNG6T (98.08 %). This strain was positive for oxidase but negative for catalase activity and acid production from glucose. Growth of strain HY02T was observed at 15-30 °C, pH 7-8 and in the presence of 0-1 % NaCl. The isolate contained MK-7 as the predominant respiratory quinone, and C18 : 0, iso-C15 : 0, summed feature 4 (anteiso-C17 : 1 B/iso-C17 : 1 I) and C16 : 0 were the major fatty acids. The major polar lipid was phosphatidylethanolamine. The genomic DNA G+C content of strain HY02T was 44.0 mol%. Phenotypic and chemotaxonomic data supported the affiliation of strain HY02T with the genus Adhaeribacter. However, strain HY02T exhibited a relatively low level of DNA-DNA relatedness with A. terreus(16.3±3.5 %). Based on its phenotypic and genotypic properties, together with its phylogenetic distinctiveness, strain HY02T should be considered a representative of a novel species in the genus Adhaeribacter, for which the name Adhaeribacter terrae sp. nov. is proposed. The type strain is HY02T (=KCTC 52512T=JCM 31652T).

Larkinella ripae sp. nov., isolated from seashore soil

Strain 15J11-11T was isolated from soil collected at the seashore and was Gram-staining-negative, short-rod-shaped, gliding and pale-pink pigmented. Flexirubin-type pigments were absent. The isolate grew at a temperature range of 15 to 30 °C and a pH range of 7 to 8. Comparative 16S rRNA gene sequence studies showed that strain 15J11-11T belonged to the genus Larkinella within the phylum Bacteroidetes and was most closely related to Larkinella arboricola Z0532T (95.6 %), Larkinella bovis M2TB15T (95.4 %), and Larkinella insperata LMG 22510T (95.2 %). The genomic DNA G+C content of strain 15J11-11T was 53.2 mol%. The strain contained phosphatidylethanolamine, phosphatidylserine, an unidentified aminophospholipid and two unidentified polar lipids as the major polar lipids; menaquinone-7 as the predominant quinone and C16 : 1ω5c, iso-C15 : 0 and iso-C17 : 0 3-OH as the major fatty acids which supported the affiliation of strain 15J11-11T to the genus Larkinella. Based on its phenotypic properties and phylogenetic distinctiveness, strain 15J11-11T represents a novel species of the genus Larkinella, for which the name Larkinella ripae sp. nov. is proposed. The type strain is 15J11-11T (=KCTC 42996T=JCM 31657T).

Occurrence of Bacterial Stem Rot of Ranunculus asiaticus Caused by Pseudomonas marginalis in Korea

In December 2016, stem rot symptoms were observed on Persian buttercup (Ranunculus asiaticus) plants in Chilgok, Gyeongbuk, Korea. In the early stage of the disease, several black spots appeared on the stem of infected plants. As the disease progressed, the infected stem cleaved and wilted. The causal agent was isolated from a lesion and incubated on Reasoner’s 2A (R2A) agar at 25°C. Total genomic DNA was extracted for phylogenetic analysis. Based on the 16S rRNA gene analysis, the isolated strain was found to belong to the genus Pseudomonas. To identify the isolated bacterial strain at the species level, the nucleotide sequences of the gyrase B (gyrB) and RNA polymerase D (rpoD) genes were obtained and compared with the sequences in the GenBank database. As the result, the causal agent of the stem rot disease was identified as Pseudomonas marginalis. To determine the pathogenicity of the isolated bacterial strain, it was inoculated into the stem of healthy R. asiaticus plant, the inoculated plant showed a lesion with the same characteristics as the naturally infected plant. Based on these results, this is the first report of bacterial stem rot on R. asiaticus caused by P. marginalis in Korea.