Heterotrophic denitrification at extremely high salt and pH by haloalkaliphilic Gammaproteobacteria from hypersaline soda lakes

In this paper we describe denitrification at extremely high salt and pH in sediments from hypersaline alkaline soda lakes and soda soils. Experiments with sediment slurries demonstrated the presence of acetate-utilizing denitrifying populations active at in situ conditions. Anaerobic enrichment cultures at pH 10 and 4 M total Na(+) with acetate as electron donor and nitrate, nitrite and N(2)O as electron acceptors resulted in the dominance of Gammaproteobacteria belonging to the genus Halomonas. Both mixed and pure culture studies identified nitrite and N(2)O reduction as rate-limiting steps in the denitrification process at extremely haloalkaline conditions.     

Natronolimnobius baerhuensis gen. nov., sp. nov. and Natronolimnobius innermongolicus sp. nov., novel haloalkaliphilic archaea isolated from soda lakes in Inner Mongolia, China

Three novel isolates of haloalkaliphilic archaea, strains IHC-005^T, IHC-010, and N-1311^T, from soda lakes in Inner Mongolia, China, were characterized to elucidate their taxonomic positions. The three strains were aerobic, Gram-negative chemoorganotrophs growing optimally at 37–45°C, pH 9.0–9.5, and 15–20% NaCl. Cells of strains IHC-005^T/IHC-010 were motile rods, while those of strain N-1311^T were non-motile pleomorphic flats or cocci. The three strains contained diphytanyl and phytanyl-sesterterpanyl diether derivatives of phosphatidylglycerol and phosphatidylglycerophosphate methyl ester. No glycolipids were detected. On phylogenetic analysis of 16S rRNA gene sequences, they formed an independent cluster in the Natro group of the family Halobacteriaceae. Comparison of their morphological, physiological, and biochemical properties, DNA G+C content and 16S rRNA gene sequences, and DNA-DNA hybridization study support the view that strains IHC-005^T/IHC-010 and strain N-1311^T represent separate species. Therefore, we propose Natronolimnobius baerhuensis gen. nov., sp. nov. for strains IHC-005^T (=CGMCC 1.3597^T =JCM 12253^T)/IHC-010 (=CGMCC 1.3598=JCM 12254) and Natronolimnobius innermongolicus sp. nov. for N-1311^T (=CGMCC 1.2124^T =JCM 12255^T).     

<Emphasis Type="Italic">Halomonas mongoliensis</Emphasis> sp. nov. and <Emphasis Type="Italic">Halomonas kenyensis</Emphasis> sp. nov., new haloalkaliphilic denitrifiers capable of N<Subscript>2</Subscript>O reduction,isolated from soda lakes

In the course of the search for N₂O-utilizing microorganisms, two novel strains of haloalkaliphilic denitrifying bacteria, Z-7009 and AIR-2, were isolated from soda lakes of Mongolia and Kenya. These microorganisms are true alkaliphiles and grow in the pH ranges of 8.0–10.5 and 7.5–10.6, respectively. They are facultative anaerobes with an oxidative type of metabolism, able to utilize a wide range of organic substrates and reduce nitrate, nitrous oxide, and, to a lesser extent, nitrite to gaseous nitrogen. They can oxidize sulfide in the presence of acetate as the carbon source and nitrous oxide (strain Z-7009) or nitrate (strain AIR-2) as the electron acceptor. The strains require Na⁺ ions. They grow at 0.16–2.2 M Na⁺ (Z-7009) and 0.04–2.2 M Na⁺ (AIR-2) in the medium. The G+C contents of the DNA of strains Z-7009 and AIR-2 are 67.9 and 65.5 mol %, respectively. According to the results of 16S rRNA gene sequencing and DNA-DNA hybridization, as well as on the basis of physiological properties, the strains were classified as new species of the genus Halomonas: Halomonas mongoliensis, with the type strain Z-7009^T (=DSM 17332, =VKM B2353), and Halomonas kenyensis, with the type strain AIR-2^T (=DSM 17331, =VKM B2354).     

Halomonas sinaiensis sp. nov., a novel halophilic bacterium isolated from a salt lake inside Ras Muhammad Park, Egypt

An alkalitolerant and halotolerant bacterium, designated strain Sharm was isolated from a salt lake inside Ras Muhammad. The morphological, physiological and genetic characteristics were compared with those of related species of the genus Halomonas. The isolate grew optimally at pH 7.0, 5–15% NaCl at 35°C. The cells were Gram-negative rods, facultative anaerobes. They accumulated glycine-betaine, as a major osmolyte, and ectoine and glutamate as minor components. The strain Sharm^T biosynthetised α-glucosidase. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and a novel phosphoglycolipid as major components. Ubiquinone with nine repetitive unities (Q9) was the only quinone found and, nC16:0 and C19:0 with cyclopropane were the main cellular fatty acids, accounting for 87.3% of total fatty acids. The G + C content of the genomic DNA was 64.7 mol %. The 16S rRNA sequence analysis indicated that strain Sharm was a member of the genus Halomonas. The closest relatives of the strain Sharm were Halomonas elongata and Halomonas eurihalina. However, DNA–DNA hybridisation results clearly indicated that strain Sham was a distinct species of Halomonas. On the basis of the evidence, we propose to assign strain Sharm as a new species of the genus Halomonas, H. sinaiensis sp. nov, with strain Sharm^T as the type strain (DSM 18067^T; ATCC BAA-1308^T). The EMBL accession number for the 16S rRNA sequence of Halomonas sinaiensis strain Sharm^T is AM238662.     

Halomonas mongoliensis sp. nov. and Halomonas kenyensis sp. nov., new haloalkaliphilic denitrifiers capable of reducing N2O, isolated from soda lakes

In the course of the search for N2O-utilizing microorganisms, two novel strains of haloalkaliphilic denitrifying bacteria, Z-7009 and AIR-2, were isolated from soda lakes of Mongolia and Kenya. These microorganisms are true alkaliphiles and grow in the pH ranges of 8.0-10.5 and 7.5-10.6, respectively. They are facultative anaerobes with an oxidative type of metabolism, able to utilize a wide range of organic substrates and reduce nitrate, nitrous oxide, and, to a lesser extent, nitrite to gaseous nitrogen. They can oxidize sulfide in the presence of acetate as the carbon source and nitrous oxide (strain Z-7009) or nitrate (strain AIR-2) as the electron acceptor. The strains require Na+ ions. They grow at medium mineralization levels of 0.16-2.2 M Na+ (Z-7009) and 0.04-2.2 M Na+ (AIR-2). The G+C contents of the DNA of strains Z-7009 and AIR-2 are 67.9 and 65.5 mol %, respectively. According to the results of 16S rRNA gene sequencing and DNA-DNA hybridization, as well as on the basis of physiological properties, the strains were classified as new species of the genus Halomonas: Halomonas mongoliensis, with the type strain Z-7009T (=DSM 17332, =VKM B2353), and Halomonas kenyensis, with the type strain AIR-2T (=DSM 17331, =VKM B2354).     

Natronosporangium hydrolyticum gen. nov., sp. nov., a haloalkaliphilic polyhydrolytic actinobacterium from a soda solonchak soil in Central Asia

During a cultural diversity survey on hydrolytic bacteria in saline alkaline soils, a hydrolytic actinobacterium strain ACPA39^T was enriched and isolated in pure culture from a soda solonchak soil in southwestern Siberia. It forms a substrate mycelium with rod-shaped sporangia containing 1–3 exospores. The isolate is obligately alkaliphilic, growing at pH 7.5–10.3 (optimum at 8.5–9.0) and moderately halophilic, tolerating up to 3 M total Na⁺ in the form of sodium carbonates. It is an obligately aerobic, organoheteroterophic, saccharolytic bacterium, utilizing various sugars and alpha/beta-glucans as growth substrates. According to the 16S rRNA gene-based phylogenetic analysis, strain ACPA39^T forms a distinct branch within the family Micromonosporaceae, with the sequence identities below 94.5% with type strains of other genera. This is confirmed by phylogenomic analysis based on the 120 conserved single copy protein-based markers and genomic indexes (ANI, AAI). The cell-wall of ACPA39^T contained meso-DAP, glycine, glutamic acid and alanine in a equimolar ratio, characteristic of the peptidoglycan type A1γ'. The whole-cell sugars include galactose and xylose. The major menaquinone is MK-10(H₄). The identified polar lipids consist of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The polar lipid fatty acids were dominated by anteiso-C_17:0, iso-C_16:0, iso-C_17:0, 10 Me-C_18:0 and C_18:1ω9. Based on the distinct phylogeny, the chemotaxonomy features and unique phenotypic properties, strain ACPA39^T (DSM 106523^T = VKM 2772^T) is classified into a new genus and species in the family Micromonosporaceae for which the name Natronosporangium hydrolitycum gen. nov., sp. nov. is proposed.     

<Emphasis Type="Italic">Halomonas chromatireducens</Emphasis> sp. nov., a new denitrifying facultatively haloalkaliphilic bacterium from solonchak soil capable of aerobic chromate reduction

A heterotrophic bacterial strain AGD 8-3 capable of denitrification under extreme haloalkaline conditions was isolated from soda solonchak soils of the Kulunda steppe (Russia). The strain was classified within the genus Halomonas. According to the results of 16S rRNA gene sequencing, Halomonas axialensis, H. meridiana, and H. aquamarina are most closely related to strain AGD 8-3 (96.6% similarity). Similar to other members of the genus, the strain can grow within a wide range of salinity and pH. The strain was found to be capable of aerobic reduction of chromate and selenite on mineral media at 160 g/l salinity and pH 9.5–10. The relatively low level of phylogenetic similarity and the phenotypic characteristics supported classification of strain AGD 8-3 as a new species Halomonas chromatireducens.     

<Emphasis Type="Italic">Tindallia texcoconensis</Emphasis> sp. nov., a new haloalkaliphilic bacterium isolated from lake Texcoco,Mexico

A new alkaliphilic and moderately halophilic, strictly anaerobic, fermentative bacterium (strain IMP-300^T) was isolated from a groundwater sample in the zone of the former soda lake Texcoco in Mexico. Strain IMP-300^T was Gram-positive, non-sporulated, motile and rod-shaped. It grew within a pH range from 7.5 to 10.5, and an optimum at 9.5. The organism was obligately dependent on the presence of sodium salts. Growth showed an optimum at 35°C with absence of growth above 45°C. It fermented peptone and a few amino acids, preferentially arginine and ornithine, with production of acetate, propionate, and ammonium. Its fatty acid pattern was mainly composed of straight chain saturated, unsaturated, and cyclopropane fatty acids. The G + C content of genomic DNA was 40.0 mol%. Analysis of the 16S rRNA gene sequence indicated that the new isolate belongs to the genus Tindallia, in the low G + C Gram-positive phylum. Phylogenetically, strain IMP-300^T has Tindallia californiensis, as closest relative with a 97.5% similarity level between their 16S rDNA gene sequences, but the DNA–DNA re-association value between the two DNAs was only 42.2%. On the basis of differences in genotypic, phenotypic, and phylogenetic characteristics, strain IMP-300^T is proposed as a new species of the genus Tindallia, T. texcoconensis sp. nov. (type strain IMP-300^T = DSM 18041^T = JCM 13990^T).     

Halomonas alkaliantarctica sp. nov., isolated from saline lake Cape Russell in Antarctica, an alkalophilic moderately halophilic, exopolysaccharide-producing bacterium

The taxomony of strain CRSS (DSM 15686(T)=ATCC BAA-848(T)) isolated from Cape Russell in Antarctica (Ross Sea, 74 52.35 S 163 53.03 E) was investigated in a polyphasic approach. The morphological, physiological and genetic characteristics were compared with that of related species of the genus Halomonas. The isolate grew optimally at pH 9.0, 10% NaCl at 30 degrees C. The cells were Gram-negative aerobic rods able to produce exopolysaccharide. They accumulated glycine-betaine, as a major osmolyte, with minor components ectoine and glutamate. The strain CRSS biosynthetised alpha-glucosidase. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol as major components. Ubiquinone with nine repetitive unities (Q9) was the only quinone found and the fatty acid composition was dominated by C18:1 (53%). The G+C content of DNA was 55.0mol% and its phylogenetic position was established by 16S rRNA gene sequencing as a member of the genus Halomonas. For physiological, chemotaxonomic and genetic features (DNA-DNA hybridisation) it is proposed to classify the isolate as a new species for which we propose the name Halomonas alkaliantarctica sp. nov.     

Utilization of aliphatic nitriles under haloalkaline conditions by Bacillus alkalinitrilicus sp. nov. isolated from soda solonchak soil

Enrichment with isobutyronitrile as the sole carbon, energy and nitrogen source at pH 10, using soda solonchak soils as an inoculum, resulted in the selection of a binary culture consisting of two different spore-forming phenotypes. One of them, strain ANL-iso4, was capable of growth with isobutyronitrile as a single substrate, while the other phenotype only utilized products of isobutyronitrile hydrolysis, such as isobutyroamide and isobutyrate. Strain ANL-iso4 is an obligate alkaliphile and a moderately salt-tolerant bacterium. Apart from isobutyronitrile, it grew on other (C3-C6) aliphatic nitriles at pH 10. Resting cells of ANL-iso4 actively hydrolyzed a number of aliphatic and arylaliphatic nitriles and their corresponding amides. The latter, together with the intermediate formation of amides during nitrile hydrolysis, indicated the presence of a nitrile hydratase/amidase system in the novel bacterium. Although present in an alkaliphilic bacterium, both nitrile- and amide-hydrolyzing activities had a pH optimum within the neutral range, probably due to their intracellular localization. On the basis of phenotypic and phylogenetic analyses, strain ANL-iso4 is proposed as a new species Bacillus alkalinitrilicus sp. nov.     

Arcobacter ellisii sp. nov., isolated from mussels

As part of a study carried out for detecting Arcobacter spp. in shellfish, three mussel isolates that were Gram-negative slightly curved rods, non-spore forming, showed a new 16S rDNA-RFLP pattern with a specific identification method for the species of this genus. Sequences of the 16S rRNA gene and those of the housekeeping genes rpoB, gyrB and hsp60 provided evidence that these mussel strains belonged to an unknown genetic lineage within the genus Arcobacter. The similarity between the 16S rRNA gene sequence of the representative strain (F79-6^T) and type strains of the other Arcobacter species ranged between 94.1% with A. halophilus and 99.1% with the recently proposed species A. defluvii (CECT 7697^T). DDH results between strain F79-6^T and the type strain of the latter species were below 70% (53 ± 3.0%). Phenotypic characteristics together with MALDITOF mass spectra differentiated the new mussel strains from all other Arcobacter species. All the results indicate that these strains represent a new species, for which the name Arcobacter ellisii sp. nov. with the type strain F79-6^T (=CECT 7837^T = LMG 26155^T) is proposed.     

Thermosediminibacter oceani gen. nov., sp. nov. and Thermosediminibacter litoriperuensis sp. nov., new anaerobic thermophilic bacteria isolated from Peru Margin

A new group of anaerobic thermophilic bacteria was isolated from enrichment cultures obtained from deep sea sediments of Peru Margin collected during Leg 201 of the Ocean Drilling Program. A total of ten isolates were obtained from cores of 1–2 m below seafloor (mbsf) incubated at 60°C: three isolates came from the sediment 426 m below sea level with a surface temperature of 9°C (Site 1227), one from 252 m below sea level with a temperature of 12°C (Site 1228), and six isolates under sulfate-reducing condition from the lower slope of the Peru Trench (Site 1230). Strain JW/IW-1228P from the Site 1228 and strain JW/YJL-1230-7/2 from the Site 1230 were chosen as representatives of the two identified clades. Based on the 16S rDNA sequence analysis, these isolates represent a novel group with Thermovenabulum and Caldanaerobacter as their closest relatives. The temperature range for growth was 52–76°C with an optimum at around 68°C for JW/IW-1228P and 43–76°C with an optimum at around 64°C for JW/YJL-1230-7/2. The pH^25C range for growth was from 6.3 to 9.3 with an optimum at 7.5 for JW/IW-1228P and from 5 to 9.5 with an optimum at 7.9–8.4 for JW/YJL-1230-7/2. The salinity range for growth was from 0% to 6% (w/v) for JW/IW-1228P and from 0% to 4.5% (w/v) for JW/YJL-1230-7/2. The G+C content of the DNA was 50 mol% for both JW/IW-1228P and JW/YJL-1230-7/2. DNA–DNA hybridization yielded 52% similarity between the two strains. According to 16S rRNA gene sequence analysis, the isolates are located within the family, Thermoanaerobacteriaceae. Based on their morphological and physiological properties and phylogenetic analysis, it is proposed that strain JW/IW-1228P^T is placed into a novel taxa, Thermosediminibacter oceani, gen. nov., sp. nov. (DSM 16646^T=ATCC BAA-1034^T), and JW/YJL-1230-7/2^T into Thermosediminibacter litoriperuensis sp. nov. (DSM 16647^T =ATCC BAA-1035^T).An erratum to this article can be found at     

Nocardia rhamnosiphila sp. nov., isolated from soil

In this study two actinomycete strains were isolated in Cape Town (South Africa), one from a compost heap (strain 202GMO^T) and the other from within the fynbos-rich area surrounded by the horseracing track at Kenilworth Racecourse (strain C2). Based on 16S rRNA gene sequence BLAST analysis, the strains were identified as members of the genus Nocardia. Phylogenetic analysis showed that the strains clustered together and are most closely related to Nocardia flavorosea NRRL B-16176^T, Nocardia testacea JCM 12235^T, Nocardia sienata IFM 10088^T and Nocardia carnea DSM 43397^T. This association was also supported by gyrB based phylogenetic analysis. The results of DNA–DNA hybridization and physiological tests allowed genotypic and phenotypic differentiation of both strains 202GMO^T and C2 from related species. However, their high DNA relatedness showed that they belong to the same species. Strain 202GMO^T was selected as the type strain to represent this novel species, for which the name Nocardia rhamnosiphila is proposed (=DSM 45147^T = NRRL B-24637^T).     

Legionella impletisoli sp. nov. and Legionella yabuuchiae sp. nov., isolated from soils contaminated with industrial wastes in Japan

In this study, we tried to isolate legionellae from nine Legionella DNA-positive soil samples collected from four different sites contaminated with industrial wastes in Japan. Using culture methods with or without Acanthamoeba culbertsoni, a total of 22 isolates of legionellae were obtained from five of the nine samples. Identification of species and/or serogroups (SGs), performed by DNA-DNA hybridization and agglutination tests, revealed that the 22 isolates consisted of ten isolates of Legionella pneumophila including five SGs, five Legionella feeleii, and one each of Legionella dumoffii, Legionella longbeachae, and Legionella jamestownensis. The species of the remaining four isolates (strains OA1-1, -2, -3, and -4) could not be determined, suggesting that these isolates may belong to new species. The 16S rDNA sequences (1476-1488bp) of the isolates had similarities of less than 95.0% compared to other Legionella species. A phylogenetic tree created by analysis of the 16S rRNA (1270bp) genes demonstrated that the isolates formed distinct clusters within the genus Legionella. Quantitative DNA-DNA hybridization tests on the OA1 strains indicated that OA1-1 should be categorized as a new taxon, whereas OA1-2, -3, and -4 were also genetically independent in another taxon. Based on the evaluated phenotypic and phylogenetic characteristics, it is proposed that one of these isolates from the soils, OA1-1, be classified as a novel species, Legionella impletisoli sp. nov.; the type strain is strain OA1-1(T) (=JCM 13919(T)=DSMZ 18493(T)). The remaining three isolates belong to another novel Legionella species, Legionella yabuuchiae sp. nov.; the type strain is strain OA1-2(T) (=JCM 14148(T)=DSMZ 18492(T)). This is the first report on the isolation of legionellae from soils contaminated with industrial wastes.     

Flavobacterium frigidimaris sp. nov., isolated from Antarctic seawater

We described the polyphasic characterization of the psychrotolerant isolated from Antarctic seawater. The strain was closely related to Flavobacterium hydatis, F. pectinovorum, and F. saccharophilum on the basis of the 16S rDNA sequence analysis. However, DNA–DNA hybridization experiments showed that the DNA-similarities between strain KUC-1^T and the reference strains of Flavobacterium were less than 30%. Therefore, we can definite a new species of Flavobacterium phylogenetically, and strain KUC-1^T can be considered to be a new species of Flavobacterium. i.e. F. frigidimaris (KUC-1^T: JCM 12218^T and DSM 15937^T; mol% G+C of DNA of the type strain is 34.5 mol%). Useful phenotypical features for discrimination of F. frigidimaris from other Flavobacterium species, such as a resistance to NaCl, optimum growth temperature, and cellular fatty acid composition, were also determined.     

Characterization of Molybdenum-Free Nitrate Reductase from Haloalkalophilic Bacterium Halomonas sp. Strain AGJ 1-3

Nitrate reductase from the haloalkalophilic denitrifying bacterium Halomonas sp. strain AGJ 1-3 was isolated and purified to homogeneity. The isolated enzyme belongs to a novel family of molybdenum-free nitrate reductases. It presents as a 130-140 kD monomeric protein with specific activity of 250 micromol/min per mg protein. The enzyme reduces not only nitrate, but also other anions, thus showing polyoxoanion reductase activity. Enzyme activity was maximal at pH 7.0 and 70-80 degrees C.     

Novel facultative anaerobic acidotolerant Telmatospirillum siberiense gen. nov. sp. nov. isolated from mesotrophic fen

Three facultative anaerobic acidotolerant Gram-negative motile spirilla strains designated 26-4b1, 26-2 and K-1 were isolated from mesotrophic Siberian fen as a component of methanogenic consortia. The isolates were found to grow chemoorganotrophically on several organic acids and glucose under anoxic and low oxygen pressure in the dark, tolerant up to 5kPa of oxygen. At low oxygen supply, faint autotrophic growth on the H(2):CO(2) mixture was also observed. All three isolates were able to fix N(2). Major cellular fatty acids were 18:1 omega7c, 17:0 cyclopropane and 16:0. Phylogenetic analyses of the 16S rRNA gene sequences revealed that they formed a deep branch within the family Rhodospirillaceae of the Alphaproteobacteria with the highest similarity of 90.9-92.5% with members of genera Phaeospirillum and Magnetospirillum. Phylogenetic study of nifH (nitrogenase) and cbbL (RuBisCO) amino acid sequence identities confirmed that the new isolates represent a novel group. Based on the phylogenetic analyses and distinct phenotypic characteristics, we are of the opinion that strains 26-4b1, 26-2 and K-1 represent a new species of a novel genus for which the name Telmatospirillum siberiense gen. nov. sp. nov. is proposed.     

Natronobacillus azotifigens gen. nov., sp. nov., an anaerobic diazotrophic haloalkaliphile from soda-rich habitats

Gram-positive bacteria capable of nitrogen fixation were obtained in microoxic enrichments from soda soils in south-western Siberia, north-eastern Mongolia, and the Lybian desert (Egypt). The same organisms were obtained in anoxic enrichments with glucose from soda lake sediments in the Kulunda Steppe (Altai, Russia) using nitrogen-free alkaline medium of pH 10. The isolates were represented by thin motile rods forming terminal round endospores. They are strictly fermentative saccharolytic anaerobes but tolerate high oxygen concentrations, probably due to a high catalase activity. All of the strains are obligately alkaliphilic and highly salt-tolerant natronophiles (chloride-independent sodaphiles). Growth was possible within a pH range from 7.5 to 10.6, with an optimum at 9.5–10, and within a salt range from 0.2 to 4 M Na⁺, with an optimum at 0.5–1.5 M for the different strains. The nitrogenase activity in the whole cells also had an alkaline pH optimum but was much more sensitive to high salt concentrations compared to the growing cells. The isolates formed a compact genetic group with a high level of DNA similarity. Phylogenetic analysis based on 16S-rRNA gene sequences placed the isolates into Bacillus rRNA group 1 as a separate lineage with Amphibacillus tropicus as the nearest relative. In all isolates the key functional nitrogenase gene nifH was detected. A new genus and species, Natronobacillus azotifigens gen. nov., sp. nov., is proposed to accommodate the novel diazotrophic haloalkaliphiles. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. The GenBank accession numbers for the 16S rRNA gene of the novel strains are EU143681-EU143690 and EU850814-EU850816; for the nifH gene the accession numbers are EU542601, EU563380-EU563386 and EU850817-EU850819.     

Candida alocasiicola sp. nov., Candida hainanensis sp. nov., Candida heveicola sp. nov. and Candida musiphila sp. nov., novel anamorphic, ascomycetous yeast species isolated from plants

In a taxonomic study on the ascomycetous yeasts isolated from plant materials collected in tropical forests in Yunnan and Hainan Provinces, southern China, four strains isolated from tree sap (YJ2E(T)) and flowers (YF9E(T), YWZH3C(T) and YYF2A(T)) were revealed to represent four undescribed yeast species. Molecular phylogenetic analysis based on the large subunit (26S) rRNA gene D1/D2 domain sequences showed that strain YJ2E(T) was located in a clade together with Candida haemulonii and C. pseudohaemulonii. Strain YF9E(T) was most closely related to C. azyma and strain YWZH3C(T) to C. sorbophila and C. spandovensis. Strain YYF2A(T) was clustered in a clade containing small-spored Metschnikowia species and related anamorphic Candida species. The new strains differed from their closely related described species by more than 10% mismatches in the D1/D2 domain. No sexual states were observed for the four strains on various sporulation media. The new species are therefore assigned to the genus Candida and described as Candida alocasiicola sp. nov. (type strain, YF9E(T) = AS 2.3484(T) = CBS 10702(T)), Candida hainanensis sp. nov. (type strain, YYF2A(T) = AS 2.3478(T) = CBS 10696(T)), Candida heveicola sp. nov. (type strain, YJ2E(T) = AS 2.3483(T) = CBS 10701(T)) and Candida musiphila sp. nov. (type strain, YWZH3C(T) = AS 2.3479(T) = CBS 10697(T)).     

Phytophthora quercetorum sp. nov., a novel species isolated from eastern and north-central USA oak forest soils

Isolates belonging to an undescribed Phytophthora species were frequently recovered during an oak forest soil survey of Phytophthora species in eastern and north-central USA in 2004. The species was isolated using an oak leaf baiting method from rhizosphere soil samples collected from Quercus rubra, Q. macrocarpa, and Q. phellos. This species is formally described as P. quercetorum. It is homothallic and has aplerotic oogonia and paragynous antheridia. It produces papillate sporangia (occasionally bipapillate) of ovoid-elongated shapes. Its temperature optimum for growth is ca 22.5 °C with the upper limit of ca 32.5 °C. P. quercetorum differs from the morphologically related P. quercina in producing distinct submerged colony-patterns, different growth-temperature requirements, and oogonial shapes and sizes. Phylogenetic analyses using seven nuclear loci supported P. quercetorum as a novel species within clade 4, closely related to P. arecae, P. palmivora, P. megakarya, and P. quercina.