Description of a phototrophic bacterium, Thiorhodococcus alkaliphilus sp. nov.

Strain JA878T was purified from a photoheterotrophic enrichment obtained from a sediment sample of a brown pond near Nari Salt Pan, Bhavnagar, Gujarat, India. Cells of the isolate were coccoid, motile by means of single polar flagellum and Gram-stain-negative. The internal photosynthetic membrane architecture was vesicular. Strain JA878T contained bacteriochlorophyll a and spirilloxanthin series of carotenoids with rhodopin (>85 %) as the major component. Strain JA878T grew optimally at pH 10-11, and had no requirement for NaCl (tolerated up to 6 %, w/v) or vitamins for growth. C16 : 1ω7c/C16 : 1ω6c, C18 : 1ω7c/C18 : 1ω6c and C16 : 0 were identified as the major fatty acids (>10 %). Phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and an unknown polar lipid were identified. Q8 was the predominant quinone system in strain JA878T. The DNA G+C content was 62.4 mol%. Highest 16S rRNA gene sequence similarity through EzTaxon-based blast analysis of strain JA878T was found with the type strains of Thiorhodococcus fuscus (99 %), Thiorhodococcus kakinadensis (98.6 %), Thiohalobacter thiocyanaticus (98.4 %), Thiophaeococcus fuscus (97.3 %) and other members of the class Gammaproteobacteria (<97.3 %), revealing a close affiliation to the genera Thiorhodococcus, Thiohalobacter and Thiophaeococcus. However, the phylogenetic treeing firmly placed the strain in the genus Thiorhodococcus. Phenotypic and chemotaxonomic evidence supported the affiliation of strain JA878T to the genus Thiorhodococcus and not to Thiohalobacter, Thiophaeococcus or other known genera of Chromatiaceae. Distinct physiological, genotypic and chemotaxonomic differences indicate that strain JA878T represents a novel species of the genus Thiorhodococcus, for which the name Thiorhodococcus alkaliphilus sp. nov. is proposed. The type strain is JA878T (=KCTC 15531T=JCM 31245T).

Rhodovulum aestuarii sp. nov., isolated from a brackish water body.

A yellowish brown, phototrophic, purple non-sulfur bacterium, strain JA924T, was isolated in pure culture from a brackish water sample collected from an estuary. Single cells were oval to rod-shaped, non-motile and Gram-stain-negative and had a vesicular architecture of intracellular photosynthetic membranes. Bacteriochlorophyll-a and carotenoids of the spheroidene series were present as photosynthetic pigments. Photolithoautotrophy, chemo-organoheterotrophy and photo-organoheterotrophy were the growth modes observed. Strain JA924T had complex growth requirements. Strain JA924T was mesophilic and moderately halophilic. The DNA G+C content was 64 mol% (HPLC). The major cellular fatty acids were C18 : 1ω7c/C18 : 1ω6c, C16 : 0 and C18 : 0. The major quinone was ubiquinone-10 (Q-10). Phosphatidylglycerol, phosphatidylethanolamine, sulfolipid and an aminolipid were the main polar lipids of strain JA924T. EzTaxon-e blast searches based on the 16S rRNA gene sequence of JA924T revealed highest similarity with Rhodovulum mangrovi AK41T (98.19 %) and other members of the genus Rhodovulum ( < 95.71 %). Strain JA924T was further identified to be distantly related to Rhodovulum mangrovi AK41T ( < 29 % based on DNA-DNA hybridization and ΔTm (>5 °C). Phenotypic, chemotaxonomic and molecular differences indicate that strain JA924T represents a novel species of the genus Rhodovulum, for which the name Rhodovulum aestuarii sp. nov. is proposed. The type strain is JA924T ( = LMG 29031T = KCTC 15485T).

Thiorhodococcus fuscus sp. nov., isolated from a lagoon.

A brown, moderately halophilic, photoautotrophic bacterium designated strain JA363T was purified from a photoheterotrophic enrichment obtained from sediment from Chilika lagoon, Odisha, India. Cells of the isolate were coccoid, motile by means of single polar flagellum and Gram-stain-negative. Strain JA363T had an obligate requirement for NaCl and could tolerate up to 7 % (w/v) NaCl. Strain JA363T had complex growth factor requirements. Internal photosynthetic membranes were present as vesicles. Strain JA363T contained bacteriochlorophyll a and spirilloxanthin series carotenoids with rhodopin as a major (>85 %) component. C16 : 1ω7c/C16 : 1ω6c, C18 : 1ω7c and C16 : 0 were the major fatty acids and phosphatidylglycerol and phosphatidylethanolamine were the major polar lipids. Q8 was the predominant quinone system of strain JA363T. The DNA G+C content was 64 mol%. The highest 16S rRNA gene sequence similarity of strain JA363T was found with the type strains of Thiorhodococcus kakinadensis (98.7 %), Thiohalobacter thiocyanaticus (98.2 %), Thiophaeococcus fuscus (97.4 %) and Thiorhodococcus bheemlicus (96.3 %). However, the phylogenetic trees generated firmly placed strain JA363T in the genus Thiorhodococcus, which was further supported by phenotypic and chemotaxonomic evidence. Consequently, strain JA363T is described as representing a novel species of the genus Thiorhodococcus as Thiorhodococcus fuscus sp. nov. The type strain is JA363T ( = KCTC 5701T = NBRC 104959T).

Caenispirillum deserti sp. nov., a spheroplast-forming bacterium isolated from a salt desert.

A Gram-stain-negative, vibrio-shaped, spheroplast-forming, motile, aerobic bacterium was isolated from the soil of a salt desert in Kutch, Gujarat, India. The strain, designated JC232(T), was oxidase- and catalase-positive. 16S rRNA gene sequence analysis indicated that strain JC232(T) was a member of the genus Caenispirillum and was related most closely to Caenispirillum salinarum AK4(T) (98.9% similarity) and Caenispirillum bisanense K92(T) (96.8%). Genome relatedness based on DNA-DNA hybridization of strain JC232(T) with the type strains of closely related species was less than 40%. The DNA G+C content of strain JC232(T) was 70 mol%. Phosphatidylglycerol, phosphatidylethanolamine, phosphotidylcholine, diphosphatidylglycerol, two unidentified amino lipids (AL1 and 2) and four unidentified lipids (UL1-4) were the polar lipids of strain JC232(T). C18 : 1ω7c/C18 : 1ω6c, C16 : 0 and C16 : 1ω7c/C16 : 1ω6c were the major (>15%) fatty acids of strain JC232(T), with minor amounts of C12 : 0, C14 : 0 3-OH/iso-C16 : 0 I, C18 : 1 2-OH, C18 : 0, C16 : 0 3-OH and C19 : 0cycloω8c. Although strain JC232(T) shared the predominant ubiquinone system (Q10) with the type strains of C. salinarum and C. bisanense, it differed from the latter in polar lipid profile, NaCl growth range and other phenotypic/physiological properties. On the basis of morphological, physiological, genotypic, phylogenetic and chemotaxonomic analyses, strain JC232(T) is considered to represent a novel species of the genus Caenispirillum, for which the name Caenispirillum deserti sp. nov. is proposed. The type strain is JC232(T) ( = KCTC 42064(T) = NBRC 110150(T)).

Lysinibacillus acetophenoni sp. nov., a solvent-tolerant bacterium isolated from acetophenone.

A Gram-stain-positive, solvent-tolerating, aerobic, rod-shaped bacterium that formed terminal endospores was isolated from the organic solvent acetophenone. The strain, designated JC23T, was oxidase- and catalase-positive. The strain grew in the presence of a wide range of organic solvents with partition coefficients (log p values) between 1 and 4, which are exceptionally toxic to micro-organisms. Based on 16S rRNA gene sequence analysis, strain JC23T was identified as belonging to the genus Lysinibacillus and was most closely related to Lysinibacillus manganicus Mn1-7T (98.5 % similarity), L. massiliensis 440831T (97.2 %) and L. chungkukjangi 2RL3-2T (96.8 %). DNA-DNA relatedness of strain JC23T with the type strains of the closest species was <39 %. Strain JC23T grew chemo-organoheterotrophically with optimal growth at pH 7 (range pH 6-9) and at 35 °C (range 25-40 °C). The DNA G+C content was 41 mol%. Major cellular fatty acids of strain JC23T were iso-C15 : 0, iso-C16 : 0, anteiso-C15 : 0 and anteiso-C17 : 0. The cell-wall peptidoglycan type was determined to be A4α (l-Lys-d-Asp), which is in agreement with the cell-wall characteristics of the genus Lysinibacillus. The predominant quinone system was MK-7. Polar lipids of strain JC23T included diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids, ß-gentiobiosyldiacylglycerol, two unidentified phospholipids and two unidentified lipids. On the basis of our morphological, physiological, genetic, phylogenetic and chemotaxonomic analyses, we conclude that strain JC23T should be assigned to a novel species of the genus Lysinibacillus, for which the name Lysinibacillus acetophenoni sp. nov. is proposed. The type strain is strain JC23T ( = CCUG 57911T = KCTC 13605T = NBRC 105754T = DSM 23394T).

Thiophaeococcus fuscus sp. nov., isolated from a lagoon.

A brown-coloured bacterium, designated strain JA633(T), was purified from a photoheterotrophic enrichment culture obtained from black sand of a lagoon. Cells of strain JA633(T) were coccoid-spherical, Gram-stain-negative and motile by means of polar flagella. Strain JA633(T) had an obligate requirement for NaCl and could tolerate up to 4% (w/v) NaCl. Internal photosynthetic membranes were present as vesicles. Photo-organoheterotrophy was the only growth mode observed. Strain JA633(T) contained bacteriochlorophyll a and a major (>85%) unidentified carotenoid of the spirilloxanthin series. Thiamine and p-aminobenzoic acid were required for growth. Major fatty acids were C(18 : 1)ω7c/C(18 : 1)ω6c, C(16 : 0) and C(16 : 1)ω7c/C(16 : 1)ω6c. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphotidylcholine and an unknown aminophospholipid were the major polar lipids in strain JA633(T). The DNA G+C content of strain JA633(T) was 64.5 mol%. Strain JA633(T) shared highest 16S rRNA gene sequence similarity with the type strains of Thiorhodococcus kakinadensis (96.9%), Thiophaeococcus mangrovi (96.3%) and Thiorhodococcus bheemlicus (96.2%), which belonged to the class Gammaproteobacteria. However, phylogenetic analysis based on 16S rRNA gene sequences showed that strain JA633(T) formed a separate clade along with Thiophaeococcus mangrovi JA304(T) whereas the members of the genus Thiorhodococcus remained as two distinct phylogenetic lineages. Based on morphological, physiological, chemotaxonomic and molecular evidence, strain JA633(T) was significantly different from the type strain of Thiophaeococcus mangrovi of the family Chromatiaceae. It is thus proposed that the strain be classified as a representative of a novel species, for which the name Thiophaeococcus fuscus sp. nov. is proposed. The type strain is JA633(T) ( = KCTC 15337(T) = NBRC 109958(T)).

Reclassification of Rhodospirillum photometricum Molisch 1907, Rhodospirillum sulfurexigens Anil Kumar et al. 2008 and Rhodospirillum oryzae Lakshmi et al. 2013 in a new genus, Pararhodospirillum gen. nov., as Pararhodospirillum photometricum comb. nov., Pararhodospirillum sulfurexigens comb. nov. and Pararhodospirillum oryzae comb. nov., respectively, and emended description of the genus Rhodospirillum.

The genus Rhodospirillum is represented by four species, with three of them showing phylogenetic divergence compared to the type species, Rhodospirillum rubrum. Differences in the major diagnostic properties such as internal photosynthetic membranes, quinones, fatty acids, carotenoid composition and a few other phenotypic properties warrant the reclassification of members of this genus. Resultantly, a new genus, Pararhodospirillum gen. nov., is proposed based on the analysis of nine strains to accommodate Rhodospirillum photometricum, Rhodospirillum sulfurexigens and Rhodospirillum oryzae as Pararhodospirillum photometricum comb. nov., Pararhodospirillum sulfurexigens comb. nov. and Pararhodospirillum oryzae comb. nov., respectively. The type species of the genus is Pararhodospirillum photometricum comb. nov. An emended description of the genus Rhodospirillum is also proposed.

Rhodospirillum oryzae sp. nov., a phototrophic bacterium isolated from rhizosphere soil of paddy.

A reddish-brown bacterium, designated strain JA318(T), was purified from a photoheterotrophic enrichment culture obtained from the rhizosphere soil of paddy. Cells of strain JA318(T) are spiral shaped, Gram-stain-negative and motile by means of amphitrichous flagella. Strain JA318(T) has no NaCl requirement for growth but can tolerate up to 1.5 % (w/v) NaCl. Internal photosynthetic membranes are present as lamellar stacks. Photoorganoheterotrophy is the only growth mode observed. Strain JA318(T) contains bacteriochlorophyll a, lycopene and rhodopin as major carotenoids. Thiamine, niacin and para-aminobenzoic acid (PABA) are required as growth factors. Major fatty acids are C18 : 1ω7c and C16 : 0. Ubiquinone-8 and rhodoquinone-8 are the observed quinones. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminolipid are the major polar lipids in strain JA318(T). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain JA318(T) clustered with species of the genus Rhodospirillum which belongs to the class Alphaproteobacteria. The highest sequence similarity of strain JA318(T) was found with Rhodospirillum sulfurexigens JA143(T) (99.9 %). The DNA-DNA reassociation values of strain JA318(T) with Rsp. sulfurexigens JA143(T) and Rhodospirillum photometricum DSM 122(T) were 52 ± 2 % and 45 ± 1 %, respectively. The genomic DNA G+C content of strain JA318(T) was 60.2 mol%. Based on the morphological, physiological, chemotaxonomical and molecular evidence, strain JA318(T) is significantly different from the type strains of species of the genus Rhodospirillum, of the family Rhodospirillaceae, and it is proposed that the strain be classified as a representative of a novel species for which the name Rhodospirillum oryzae sp. nov. is proposed. The type strain is JA318(T) (= KCTC 5960(T) = NBRC 107573(T)).

Phaeospirillum oryzae sp. nov., a spheroplast-forming, phototrophic alphaproteobacterium from a paddy soil.

Two strains (JA317(T) and JA559) of spiral shaped, spheroplast-forming, anaerobic, gram-negative, motile purple non-sulfur bacteria were isolated from rhizosphere soils of paddy and were characterized by a polyphasic taxonomic approach. Bacteriochlorophyll a and carotenoids, rhodopin, lycopene and rhodopin glucoside, were present as photosynthetic pigments. Intracellular photosynthetic membranes were of stacked type. The major fatty acids were C(18 : 1)ω7c, C(16 : 0) and C(16 : 1)ω6c/C(16 : 1)ω7c in both strains. The genomic DNA G+C content was 63.3±0.8 mol%. The two strains were closely related (mean DNA-DNA hybridization >85 %). Phylogenetic analysis showed that the strains clustered with the species of the genus Phaeospirillum, which belongs to the family Rhodospirillaceae within the class Alphaproteobacteria. Based on 16S rRNA gene sequence analysis, strains JA317(T) and JA559 showed highest sequence similarity with the type strains of Phaeospirillum chandramohanii (98.2 %), Phaeospirillum molischianum (97.4 %) and Phaeospirillum fulvum (97.1 %) of the family Rhodospirillaceae. Strain JA317(T) can be clearly distinguished from P. chandramohanii with respect to spheroplast formation and several other morphological and physiological properties. DNA-DNA relatedness of strain JA317(T) with its closest relatives of the genus Phaeospirillum was less than 55 %. It is evident from the phenotypic, chemotaxonomic and molecular genetic evidence that strain JA317(T) represents a novel species of the genus Phaeospirillum, for which the name Phaeospirillum oryzae sp. nov., is proposed. The type strain of the species is JA317(T) ( = NBRC 104938(T)  = KCTC 5704(T)).

Phaeovibrio sulfidiphilus gen. nov., sp. nov., phototrophic alphaproteobacteria isolated from brackish water.

Two strains (JA480(T) and JA481) of phototrophic alphaproteobacteria were isolated from sediment samples collected from brackish water near Nagapattinam, India. They were Gram-negative, vibrioid cells containing bacteriochlorophyll a and rhodopin as major photosynthetic pigments. Most cells of both strains were non-flagellated; 1 % of cells showed two monopolar flagella. Cells showed positive phototaxis. Both strains showed chimeric intracellular photosynthetic membranes, where both lamellar stacks and vesicles were present together in a single cell. The major fatty acids were C(18 : 1)ω7c and C(16 : 0) in both strains. The genomic G+C content was 67.2-68.8 mol% and the two strains were closely related (mean DNA-DNA hybridization >85 %). 16S rRNA gene sequence comparisons indicated that the isolates represent members of the Rhodospirillaceae within the class Alphaproteobacteria. According to the sequence comparison data, strain JA480(T) is positioned distinctly outside the group formed by the phototrophic genera Rhodospirillum, Rhodocista, Phaeospirillum, Rhodovibrio, Rhodospira and Roseospira, with only 80-92 % 16S rRNA gene sequence similarity. Distinct morphological, physiological and genotypic differences from previously described taxa support the classification of this isolate as a representative of a novel species in a new genus, for which the name Phaeovibrio sulfidiphilus gen. nov., sp. nov. is proposed. The type strain of Phaeovibrio sulfidiphilus is JA480(T) ( = KCTC 5825(T)  = NBRC 106163(T)  = DSM 23193(T)).

Rhodoplanes pokkaliisoli sp. nov., a phototrophic alphaproteobacterium isolated from a waterlogged brackish paddy soil.

A Gram-negative, rod-shaped, purple non-sulfur bacterial strain, designated JA415T, was isolated from the mud of a pokkali rice field located on Vypeen Island, Ernakulam, Kerala, India. Strain JA415T was motile by means of a single polar flagellum. Photo- and chemo-organoheterotrophic growth was observed using organic compounds as carbon sources and electron donors. Photo- and chemolithoautotrophic growth using thiosulfate as electron donor did not occur. Fermentative growth could not be demonstrated. Intracellular photosynthetic membranes were lamellar stacks parallel to the cytoplasmic membrane. Bacteriochlorophyll a and carotenoids of the spirilloxanthin series were present as photosynthetic pigments. Niacin, pantothenate and p-aminobenzoate were required as growth factors. C18:1omega7c was the predominant cellular fatty acid component. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JA415T clustered with members of the genus Rhodoplanes in the class Alphaproteobacteria. On the basis of phenotypic and molecular genetic evidence, it is proposed that strain JA415T be classified as a representative of a novel species of the genus Rhodoplanes, family Hyphomicrobiaceae, with the name Rhodoplanes pokkaliisoli sp. nov. The type strain is JA415T (=KCTC 5711T=NBRC 104972T).