Mei-Hua Hung

Azospirillum rugosum sp nov., isolated from oil-contaminated soil

The taxonomic status of a light-orange-coloured bacterial isolate from an oil-contaminated soil sample was characterized by using a polyphasic taxonomic approach. Comparative analysis of 16S rRNA gene sequences demonstrated that the isolate belonged phylogenetically to the genus Azospirillum, with Azospirillum canadense, Azospirillum brasilense and Azospirillum doebereinerae as its closest phylogenetic relatives (97.3, 97.0 and 97.0 % similarity, respectively). DNA-DNA pairing studies showed that the unidentified organism displayed 25.0, 17.0 and 19.0 % relatedness to the type strains of A. brasilense, A. canadense and A. doebereinerae, respectively. The generic assignment was confirmed by chemotaxonomic data, which revealed a fatty acid profile that was characteristic of the genus Azospirillum, consisting of straight-chain saturated and unsaturated fatty acids with C18 : 1 omega 7c as the major fatty acid, and ubiquinone with ten isoprene units (Q-10) as the predominant respiratory quinone. On the basis of both the phenotypic and molecular genetic evidence, it is proposed that the unknown isolate be classified as a representative of a novel species of the genus Azospirillum, for which the name Azospirillum rugosum sp. nov. is proposed. The type strain is IMMIB AFH-6T (=CCUG 53966T=DSM 19657T).

Phosphate-solubilizing soil yeast Meyerozyma guilliermondii CC1 improves maize (Zea mays L.) productivity and minimizes requisite chemical fertilization

AimPhosphate-solubilizing yeasts have been under-exploited in eco-friendly maize cultivation. In this regard, soil yeasts Meyerozyma guilliermondii CC1, Rhodotorula mucilaginosa CC2 and M. caribbica CC3 were investigated for their plant growth-promoting (PGP) activities.MethodsSoil yeasts were isolated and characterized. Maize (Zea mays L. cv. Tainong No.1) and Chinese cabbage (Brassica rapa L. cv. Pekinensis) were used for seed bioassay. Growth-promoting effects of yeasts under greenhouse conditions were evaluated using maize and lettuce (Lactuca sativa L. cvs. Capitata and Taiwan sword leaf). Ultimately, M. guilliermondii CC1 was tested on field-grown maize; treatments included full-dose chemical fertilizers (CF), yeast (CC1), half-dose chemical fertilizers (½CF), CC1 + ½CF and control. Nutrient uptake, growth, and yield of maize and rhizospheric soil microbes were estimated.ResultsStrain M. guilliermondii CC1 exhibited better seed vigor index in maize and Chinese cabbage. CC1 + ½CF significantly improved the dry-weights, and nutrient uptakes of maize and sword leaf lettuce under greenhouse conditions. In field, CC1 + ½CF application exerted a pronounced effect on growth of maize, cob yield, nutrient-uptake and rhizospheric soil microbial counts.ConclusionOur results validated superior biochemical potency and PGP traits of M. guilliermondii CC1 that reduced requisite chemical fertilizer application without affecting the optimal productivity in maize.

Belliella pelovolcani sp. nov., isolated from a mud-volcano in Taiwan.

Strain CC-SAL-25(T), a non-motile, Gram-negative, red-pigmented bacterium, was isolated from a rare mud-volcano, located in Wandan, Pingtung County, Taiwan. Studies based on 16S rRNA gene sequences showed that the strain clustered closely with Belliella baltica BA143(T) (95.4 % sequence similarity). A menaquinone with seven isoprene units (MK-7) was the major respiratory quinone. The fatty acid profile was slightly different from that of B. baltica BA143(T). The results of the physiological and biochemical tests showed that strain CC-SAL-25(T) could be clearly differentiated from recognized Belliella species based on phenotypic properties. It was evident from the genotypic and phenotypic data that strain CC-SAL-25(T) should be classified as representing a second novel species in the genus Belliella. The name proposed for this taxon is Belliella pelovolcani sp. nov., and the type strain is CC-SAL-25(T) (=BCRC 17883(T)=KCTC 13248(T)).

Cohnella formosensis sp. nov., a xylanolytic bacterium isolated from the rhizosphere of Medicago sativa L.

A Gram-positive, spore-forming, aerobic, rod-shaped, xylanolytic bacterium designated strain CC-Alfalfa-35(T) was isolated from the rhizosphere of Medicago sativa L. in Taiwan. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain CC-Alfalfa-35(T) was affiliated to the genus Cohnella. Strain CC-Alfalfa-35(T) shared 95.3 % pairwise 16S rRNA gene sequence similarity to the type strain of the type species of the genus Cohnella (Cohnella thermotolerans DSM 17683(T)) besides showing a similarity of 97.4-93.6 % with other recognized species of the genus Cohnella. The DNA-DNA hybridization value between CC-Alfalfa-35(T) and Cohnella thailandensis KCTC 22296(T) was 37.7 % ± 1.7 % (reciprocal value, 55.7 % ± 3.0 %). Predominant cellular fatty acids were iso-C16 : 0 and anteiso-C15 : 0. The polar lipid profile constituted diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, lysyl-phosphatidylglycerol, three unidentified phospholipids and three unidentified aminophospholipids. The major respiratory quinone was MK-7 and the DNA G+C content was 58.3 mol%. Strain CC-Alfalfa-35(T) contained meso-diaminopimelic acid as the major diamino acid in the cell-wall peptidoglycan. Based on the polar lipid and fatty acid profiles, which were in line with those of C. thermotolerans DSM 17683(T), coupled with additional distinguishing genotypic, phenotypic and chemotaxonomic features, strain CC-Alfalfa-35(T) is proposed to represent a novel species within the genus Cohnella, for which the name Cohnella formosensis sp. nov. is proposed. The type strain is CC-Alfalfa-35(T) ( = JCM 18405(T) = BCRC 80428(T)).

Paenibacillus medicaginis sp. nov. a chitinolytic endophyte isolated from the root nodule of alfalfa (Medicago sativa L.).

A Gram-stain-variable, short-rod-shaped, endospore-forming, strictly aerobic, non-motile, chitinolytic and endophytic bacterium, designated strain CC-Alfalfa-19T, exhibiting unusual bipolar appendages was isolated from a root nodule of alfalfa (Medicago sativa L.) in Taiwan and subjected to a polyphasic taxonomic study. Based on 16S rRNA gene sequence analysis, strain CC-Alfalfa-19T was found to be most closely related to Paenibacillus puldeungensis CAU 9324T (95.2 %), whereas other species of the genus Paenibacillus shared ≤ 95.0 % sequence similarity. The phylogenetic analysis revealed a distinct phyletic lineage established by strain CC-Alfalfa-19T with respect to other species of the genus Paenibacillus. Fatty acids comprised predominantly anteiso-C15 : 0, C16 : 0, anteiso-C17 : 0 and iso-C16 : 0. Menaquinone 7 (MK-7) was identified as the sole respiratory quinone and the genomic DNA G+C content was 42.7 mol%. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, an unidentified glycolipid and an unidentified lipid. The diagnostic diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. Based on the polyphasic taxonomic evidence that was in line with the genus Paenibacillus and additional distinguishing characteristics, strain CC-Alfalfa-19T is considered to represent a novel species, for which the name Paenibacillus medicaginis sp. nov. (type strain CC-Alfalfa-19T = BCRC 80441T = JCM 18446T) is proposed.A Gram-stain-variable, short-rod-shaped, endospore-forming, strictly aerobic, non-motile, chitinolytic and endophytic bacterium, designated strain CC-Alfalfa-19T, exhibiting unusual bipolar appendages was isolated from the root nodule of alfalfa (Medicago sativa L.) in Taiwan and subjected to a polyphasic taxonomy. Based on 16S rRNA gene sequence analysis, strain CC-Alfalfa-19T was found to be most closely related to Paenibacillus puldeungensis CAU 9324T (95.2 %), whereas other Paenibacillus species shared ≤95.0 % sequence similarity. The phylogenetic analysis revealed a distinct phyletic lineage established by strain CC-Alfalfa-19T with respect to other Paenibacillus species. Fatty acids comprised predominantly anteiso-C15:0, C16:0, anteiso-C17:0 and iso-C16. Menaquinone 7 (MK-7) was identified as the sole respiratory quinone and the genomic DNA G+C content was 42.7 mol%. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, an unidentified glycolipid and an unidentified lipid. The diagnostic diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. Based on the polyphasic taxonomic evidences that were in line with the genus Paenibacillus and additional distinguishing characteristics, strain CC-Alfalfa-19T is considered to represent a novel species, for which the name Paenibacillus medicaginis sp. nov. (type strain CC-Alfalfa-19T = BCRC 80441T = JCM 18446T) is proposed.

Rhizobium straminoryzae sp. nov., isolated from the surface of rice straw.

An aerobic, Gram-stain-negative, rod-shaped bacterium, designated strain CC-LY845(T), was isolated from the surface of rice straw in Taiwan. Cells were non-motile, and no flagellum was detected. Comparison of 16S rRNA gene sequences indicated that the strain was phylogenetically related to species of the genus Rhizobium, with closest similarity to Rhizobium pseudoryzae KCTC 23294(T) (97.6 %), R. rhizoryzae KCTC 23652(T) (97.0 %) and R. oryzae LMG 24253(T) (96.7 %); other species showed lower levels of similarity (<96.6 %). The DNA-DNA relatedness of strain CC-LY845(T) and R. pseudoryzae KCTC 23294(T) was 34.8±3.1 % (reciprocal value 39.2±2.2 %). Phylogenetic analysis based on the housekeeping atpD and recA genes showed that the novel strain could be distinguished from R. pseudoryzae KCTC 23294(T) (92.7 and 91.5 %, respectively) and other species of the genus Rhizobium. The temperature range for growth was 25-42 °C, the pH range was 5.0-9.0 and NaCl concentrations up to 4.0 % (w/v) were tolerated. Strain CC-LY845(T) did not form nodules on four different legumes, and the nodD and nifH genes were not detected by PCR. The major fatty acids were C16 : 0 and summed feature 8 (C18 : 1ω7c/C18 : 1ω6c). The polyamine pattern of strain CC-LY845(T) showed spermidine and putrescine as major polyamines. The predominant quinone system was ubiquinone 10 (Q-10). The DNA G+C content was 68.3±2.4 mol%. Base on its phylogenetic, phenotypic and chemotaxonomic features, strain CC-LY845(T) is proposed to represent a novel species within the genus Rhizobium, for which the name Rhizobium straminoryzae sp. nov. is proposed. The type strain is strain CC-LY845(T) ( = BCRC 80698(T) = JCM 19536(T)).

Pseudoxanthobacter soli gen. nov., sp. nov., a nitrogen-fixing alphaproteobacterium isolated from soil.

A Gram-type negative or variable, aerobic, rod-shaped, nitrogen-fixing bacterium, designated strain CC4(T), was isolated on nutrient agar from a soil sample collected at a regional agricultural research field station located in Kaohsiung County, Taiwan. 16S rRNA gene sequence analysis demonstrated that this isolate is unique, showing <92.5 % similarity with respect to species of the genera Xanthobacter (maximum of 92.2 % similarity), Prosthecomicrobium (92.0 %), Devosia (91.9 %), Kaistia (91.9 %) and Methylocystis (91.9 %). The organism utilized acetic acid, formic acid, beta-hydroxybutyric acid, dl-lactic acid, succinic acid, bromosuccinic acid, l-alaninamide, l-alanine, l-alanyl glycine, l-glutamic acid and l-proline as substrates, but not methanol or methylamine. Chemotaxonomic data revealed that strain CC4(T) contains ubiquinone Q-10 as the major respiratory quinone. The characteristic diamino acid of the peptidoglycan was meso-diaminopimelic acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, an unknown lipid and an unknown aminolipid. The fatty acid profile differed from those of members of the genera Xanthobacter, Prosthecomicrobium, Devosia and Kaistia. The predominant fatty acids were C(18 : 1)omega7c, C(19 : 0) cyclo and C(16 : 0). On the basis of 16S rRNA gene sequence analysis in combination with chemotaxonomic and physiological data, strain CC4(T) represents a novel genus and species, for which we propose the name Pseudoxanthobacter soli gen. nov., sp. nov. The type strain of Pseudoxanthobacter soli is CC4(T) (=DSM 19599(T) =CIP 109513(T)).

Pseudomonas matsuisoli sp. nov., isolated from a soil sample.

An aerobic, Gram-stain-negative, rod-shaped and polar-flagellated bacterium, designated strain CC-MHH0089(T), was isolated from a soil sample taken on Matsu Island (Taiwan). Strain CC-MHH0089(T) grew at 15-30 °C and pH 5.0-10.0 and tolerated ≤8 % (w/v) NaCl. 16S rRNA gene sequence analysis showed high pairwise sequence similarity to Pseudomonas azotifigens 6H33b(T) (97.3 %) and Pseudomonas balearica SP1402(T) (96.7 %) and lower sequence similarity to other strains (<96.0 %). In DNA-DNA reassociation experiments, the relatedness of strain CC-MHH0089(T) to P. azotifigens JCM 12708(T) was 38.3 % (reciprocal value 19.5 %). Evolutionary trees reconstructed on the basis of 16S rRNA, gyrB and rpoB gene sequences revealed a varying phylogenetic neighbourhood of strain CC-MHH0089(T) with regard to the most closely related type strains. The predominant quinone system was ubiquinone 9 (Q-9) and the DNA G+C content was 63.6 mol%. The major fatty acids were C12 : 0, C16 : 0, C17 : 0, C19 : 0 cyclo ω8c and summed features 2 (C14 : 0 3-OH/iso-C16 : 1 I), 3 (C16 : 1ω7c/C16 : 1ω6c) and 8 (C18 : 1ω7c/C18 : 1ω6c). The major polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. According to its distinct phylogenetic, phenotypic and chemotaxonomic features, strain CC-MHH0089(T) is proposed to represent a novel species within the genus Pseudomonas, for which the name Pseudomonas matsuisoli sp. nov. is proposed. The type strain is CC-MHH0089(T) ( = BCRC 80771(T) = JCM 30078(T)).

Ruficoccus amylovorans gen. nov., sp. nov., an amylolytic and nitrate-reducing diazotroph of the family Puniceicoccaceae

A novel amylolytic, nitrate-reducing and diazotrophic bacterium, designated strain CC-MHH0563T, isolated from a fermenter was assessed for its taxonomic status using a polyphasic approach. Cells of strain CC-MHH0563T were Gram-staining-negative, catalase- and oxidase-positive, mesophilic and aerobic cocci, which produced reddish nondiffusible pigments. Growth was observed at 15-37 °C (optimal 25 °C), pH 6.0-8.0 (optimal pH 7.0) and salinity of 0-3 % (w/v). Strain CC-MHH0563T showed highest pairwise 16S rRNA gene sequence similarity to members of the genera Cerasicoccus(89.3-89.5 %), Coraliomargarita (87.8 %), Pelagicoccus(85.8-86.4 %) and Puniceicoccus (87.9 %), and established a discrete taxonomic lineage during phylogenetic analysis. The major fatty acids found in strain CC-MHH0563T were C14 : 0, anteiso-C15 : 0, C16 : 0, C17 : 0, C18 : 0 and C18 : 1ω9c. The polar lipid profile consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, two unknown aminolipids and two unknown aminophospholipids. The polyamine pattern showed a predominance of spermidine and a minor amount of cadaverine. The DNA G+C content was 57.4 mol% and the predominant quinone system was menaquinone-7. The low 16S rRNA gene sequence similarity values (<90.0 %) and a distinct phylogenetic clustering clearly distinguished strain CC-MHH0563T from other representatives of the family Puniceicoccaceae. Based on the discrete phylogenetic, phenotypic and chemotaxonomic traits together with the results of comparative 16S rRNA gene sequence analysis, strain CC-MHH0563T is considered to represent a novel genus and species of the family Puniceicoccaceae, for which the name Ruficoccus amylovorans gen. nov., sp. nov. is proposed. The type strain of the type species is CC-MHH0563T (=BCRC 80918T=JCM 31066T).

Sphingomonas colocasiae sp. nov., isolated from taro (Colocasia esculanta)

A polyphasic approach was used to characterize an aerobic, Gram-stain-negative, rod-shaped bacterium (designed as strain CC-MHH0539T) isolated from the chopped tuber of taro (Colocasia esculanta) in Taiwan. Strain CC-MHH0539T was able to grow at 15-30 °C (optimum, 25 °C), at pH 6.0-9.0 (optimum, 7.0) and with 0-1 % (w/v) NaCl. Strain CC-MHH0539T showed highest 16S rRNA gene sequence similarity to Sphingomonas laterariae LNB2T (96.8 %), Sphingobium boeckii 469T (96.5 %), Sphingomonas faucium E62-3T (96.4 %) and Sphingosinicella vermicomposti YC7378T (96.2 %) and <96.1 % similarity to other sphingomonads. Strain CC-MHH0539T was found to cluster mainly with the clade that accommodated members of the genus Sphingomonas. The dominant cellular fatty acids were C16 : 0, C16 : 1ω5c, C14 : 0 2-OH, C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, two sphingoglycolipids and two unidentified phospholipids were detected in strain CC-MHH0539T. The DNA G+C content was 69.5 mol%. The respiratory quinone system and predominant polyamine was ubiquinone 10 (Q-10) and sym-homospermidine, respectively, which is in line with Sphingomonas representatives. Based on the distinct phylogenetic, phenotypic and chemotaxonomic traits, strain CC-MHH0539T is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas colocasiae sp. nov. is proposed. The type strain is CC-MHH0539T (=BCRC 80933T=JCM 31229T).