Endophytic fungi harbored in Panax notoginseng: diversity and potential as biological control agents against host plant pathogens of root-rot disease.

BACKGROUND: Endophytic fungi play an important role in balancing the ecosystem and boosting host growth. In the present study, we investigated the endophytic fungal diversity of healthy Panax notoginseng and evaluated its potential antimicrobial activity against five major phytopathogens causing root-rot of P. notoginseng. METHODS: A culture-dependent technique, combining morphological and molecular methods, was used to analyze endophytic fungal diversity. A double-layer agar technique was used to challenge the phytopathogens of P. notoginseng. RESULTS: A total of 89 fungi were obtained from the roots, stems, leaves, and seeds of P. notoginseng, and 41 isolates representing different morphotypes were selected for taxonomic characterization. The fungal isolates belonged to Ascomycota (96.6%) and Zygomycota (3.4%). All isolates were classified to 23 genera and an unknown taxon belonging to Sordariomycetes. The number of isolates obtained from different tissues ranged from 12 to 42 for leaves and roots, respectively. The selected endophytic fungal isolates were challenged by the root-rot pathogens Alternaria panax, Fusarium oxysporum, Fusarium solani, Phoma herbarum, and Mycocentrospora acerina. Twenty-six of the 41 isolates (63.4%) exhibited activity against at least one of the pathogens tested. CONCLUSION: Our results suggested that P. notoginseng harbors diversified endophytic fungi that would provide a basis for the identification of new bioactive compounds, and for effective biocontrol of notoginseng root rot.

Naumannella huperziae sp. nov., an endophytic actinobacterium isolated from Huperzia serrata (Thunb.).

An endophytic, short rod-shaped, non-motile and non-spore-forming actinobacterium, designated strain CPCC 204135T, was isolated from a surface-sterilized medicinal plant, Huperzia serrata (Thunb.), collected from Sichuan Province, south-west China. Strain CPCC 204135T was observed to grow at temperatures between 20 and 37 °C (optimum, 28-32 °C), at pH 6.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 0-9.0 % (w/v) NaCl (optimum, 0-3 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CPCC 204135T belonged to the genus Naumannella, showing the highest level of 16S rRNA gene sequence similarity with Naumannella halotolerans DSM 24323T (97.2 %), the only species of the genus Naumannella in the family Propionibacteriaceaewith avalidly published name. The DNA-DNA hybridization value between strain CPCC 204135T and N. halotolerans DSM 24323T was 20.1±1.8 %, which is far below the accepted 70 % threshold for species delineation. The cell-wall hydrolysates contained ll-diaminopimelic acid, alanine, glycine and glutamic acid, with the peptidoglycan type of A3γ. Diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid, one unidentified aminolipid, one unidentified polar lipid and several kinds of glycolipids were detected in the polar lipids profile. MK-9(H4) was identified as the predominant menaquinone. The major cellular fatty acids (>10 %) were anteiso-C15 : 0 and iso-C16 : 0. The G+C content of the genomic DNA of strain CPCC 204135T was determined to be 71.8 mol%. On the basis of phylogenetic analysis, and phenotypic and chemotaxonomic characteristics, we concluded that strain CPCC 204135T represents a novel species of the genus Naumannella, for which the name Naumannella huperziae sp. nov. is proposed, with strain CPCC 204135T (=DSM 101717T=NBRC 111773T) as the type strain.

Diversity, distribution, and antagonistic activities of rhizobacteria of Panax notoginseng.

BACKGROUND: Rhizobacteria play an important role in plant defense and could be promising sources of biocontrol agents. This study aimed to screen antagonistic bacteria and develop a biocontrol system for root rot complex of Panax notoginseng. METHODS: Pure-culture methods were used to isolate bacteria from the rhizosphere soil of notoginseng plants. The identification of isolates was based on the analysis of 16S ribosomal RNA (rRNA) sequences. RESULTS: A total of 279 bacteria were obtained from rhizosphere soils of healthy and root-rot notoginseng plants, and uncultivated soil. Among all the isolates, 88 showed antagonistic activity to at least one of three phytopathogenic fungi, Fusarium oxysporum, Fusarium solani, and Phoma herbarum mainly causing root rot disease of P. notoginseng. Based on the 16S rRNA sequencing, the antagonistic bacteria were characterized into four clusters, Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetesi. The genus Bacillus was the most frequently isolated, and Bacillus siamensis (Hs02), Bacillus atrophaeus (Hs09) showed strong antagonistic activity to the three pathogens. The distribution pattern differed in soil types, genera Achromobacter, Acidovorax, Brevibacterium, Brevundimonas, Flavimonas, and Streptomyces were only found in rhizosphere of healthy plants, while Delftia, Leclercia, Brevibacillus, Microbacterium, Pantoea, Rhizobium, and Stenotrophomonas only exist in soil of diseased plant, and Acinetobacter only exist in uncultivated soil. CONCLUSION: The results suggest that diverse bacteria exist in the P. notoginseng rhizosphere soil, with differences in community in the same field, and antagonistic isolates may be good potential biological control agent for the notoginseng root-rot diseases caused by F. oxysporum, Fusarium solani, and Panax herbarum.

Abundant and diverse endophytic actinobacteria associated with medicinal plant Maytenus austroyunnanensis in Xishuangbanna tropical rainforest revealed by culture-dependent and culture-independent methods.

Endophytes are now considered as an important component of biodiversity. However, the diversity of endophytic actinobacteria associated with tropical rainforest native medicinal plants is essentially unknown. In this study, the diversity of endophytic actinobacteria residing in root, stem and leaf tissues of medicinal plant Maytenus austroyunnanensis collected from tropical rainforest in Xishuangbanna, China was investigated with a combination of cultivation and culture-independent analysis on the basis of 16S rRNA gene sequencing. By using different selective isolation media and methods, a total of 312 actinobacteria were obtained, and they were affiliated with the order Actinomycetales (distributed into 21 genera). Based on a protocol for endophytes enrichment, three 16S rRNA gene clone libraries were constructed and 84 distinct operational taxonomic units were identified and they distributed among the orders Actinomycetales and Acidimicrobiales, including eight suborders and at least 38 genera with a number of rare actinobacteria genera. Phylogenetic analysis showed that 32% of the clones in the libraries had lower than 97% similarities with related type strains. Interestingly, six genera from the order Actinomycetales and uncultured clones from Acidimicrobiales have not, to our knowledge, been previously reported as endophytes. Our study confirms abundant endophytic actinobacterial consortium in tropical rainforest native plant and suggests that this special habitat represents an underexplored reservoir of diverse and novel actinobacteria of potential interest for bioactive compounds discovery.

Saccharopolyspora gloriosae sp. nov., an endophytic actinomycete isolated from the stem of Gloriosa superba L.

A Gram-stain-positive, aerobic actinomycete, strain YIM 60513(T), was isolated from the stem of Gloriosa superba L. collected from tropical rainforest at Xishuangbanna, Yunnan Province, south-west China. 16S rRNA gene sequence analysis indicated that strain YIM 60513(T) belonged to the genus Saccharopolyspora and was closely related to Saccharopolyspora gregorii NCIB 12823(T) (99.1 % similarity) and Saccharopolyspora cebuensis SPE 10-1(T) (97.3 % similarity). Data for the predominant quinone [MK-9(H(4))], major fatty acids (iso-C(16 : 0), anteiso-C(17 : 0) and C(17 : 1) cis9) and G+C content of the genomic DNA (71.6 mol%) were similar to those for members of the genus Saccharopolyspora. The level of DNA-DNA relatedness between strain YIM 60513(T) and S. gregorii NCIB 12823(T) was 43 %. The combination of phylogenetic analysis, phenotypic differences, chemotaxonomic characteristics and DNA-DNA hybridization data supported the view that strain YIM 60513(T) should be distinguished from S. gregorii NCIB 12823(T) and S. cebuensis SPE 10-1(T). Strain YIM 60513(T) therefore represents a novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora gloriosae sp. nov. is proposed. The type strain is YIM 60513(T) (=KCTC 19243(T) =CCTCC AA 207006(T)).

Isolation, diversity, and antimicrobial activity of rare actinobacteria from medicinal plants of tropical rain forests in Xishuangbanna, China.

Endophytic actinobacteria are relatively unexplored as potential sources of novel species and novel natural products for medical and commercial exploitation. Xishuangbanna is recognized throughout the world for its diverse flora, especially the rain forest plants, many of which have indigenous pharmaceutical histories. However, little is known about the endophytic actinobacteria of this tropical area. In this work, we studied the diversity of actinobacteria isolated from medicinal plants collected from tropical rain forests in Xishuangbanna. By the use of different selective isolation media and methods, a total of 2,174 actinobacteria were isolated. Forty-six isolates were selected on the basis of their morphologies on different media and were further characterized by 16S rRNA gene sequencing. The results showed an unexpected level of diversity, with 32 different genera. To our knowledge, this is the first report describing the isolation of Saccharopolyspora, Dietzia, Blastococcus, Dactylosporangium, Promicromonospora, Oerskovia, Actinocorallia, and Jiangella species from endophytic environments. At least 19 isolates are considered novel taxa by our current research. In addition, all 46 isolates were tested for antimicrobial activity and were screened for the presence of genes encoding polyketide synthetases and nonribosomal peptide synthetases. The results confirm that the medicinal plants of Xishuangbanna represent an extremely rich reservoir for the isolation of a significant diversity of actinobacteria, including novel species, that are potential sources for the discovery of biologically active compounds.

Glycomyces scopariae sp. nov. and Glycomyces mayteni sp. nov., isolated from medicinal plants in China.

Two actinomycete strains, designated YIM 56256(T) and YIM 61331(T), were isolated from the roots of Scoparia dulcis and Maytenus austroyunnanensis, two Chinese medicinal plants, and their taxonomic status was established based on a polyphasic investigation. The organisms were found to have chemical and morphological markers typical of members of the genus Glycomyces. 16S rRNA gene sequence analysis showed that they were closely related to each other and to Glycomyces sambucus E71(T). A battery of physiological characteristics and levels of DNA-DNA relatedness indicated that strains YIM 56256(T) and YIM 61331(T) represent two novel species, clearly different from the related known Glycomyces species. On the basis of the data presented, it is evident that each of these strains represents a novel species of the genus Glycomyces, for which the names Glycomyces scopariae sp. nov. (type strain YIM 56256(T) =KCTC 19158(T) =DSM 44968(T)) and Glycomyces mayteni sp. nov. (type strain YIM 61331(T) =KCTC 19527(T) =CCTCC AA 208004(T)) are proposed.

Micrococcus endophyticus sp. nov., isolated from surface-sterilized Aquilaria sinensis roots.

A Gram-positive bacterial strain, designated YIM 56238(T), was isolated from plant roots (Aquilaria sinensis), and characterized by using a polyphasic approach. Strain YIM 56238(T) grew optimally at pH 7.0-8.0 and at 28 degrees C. Analysis of the 16S rRNA gene sequence of strain YIM 56238(T) indicated that it belongs to the genus Micrococcus. Chemotaxonomic data strongly supported the classification of this strain within the genus Micrococcus: the cell-wall peptidoglycan contained lysine, glutamic acid, alanine and glycine; the predominant menaquinones were MK-8(H(2)) (63.6 %) and MK-7(H(2)) (21.1 %); the phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown ninhydrin-negative phospholipid; and the major cellular fatty acids were iso-C(15 : 0) (30.95 %) and anteiso-C(15 : 0) (53.75 %). The G+C content of the genomic DNA was 72.9 mol%. A number of physiological features were found that clearly distinguished strain YIM 56238(T) from recognized species of the genus Micrococcus. DNA-DNA hybridization studies suggested that the novel strain represents a separate genomic species. On the basis of the data, therefore, strain YIM 56238(T) represents a novel species of the genus Micrococcus, for which the name Micrococcus endophyticus sp. nov. is proposed. The type strain is YIM 56238(T) (=DSM 17945(T)=KCTC 19156(T)).

Pseudonocardia endophytica sp. nov., isolated from the pharmaceutical plant Lobelia clavata.

An endophytic actinomycete strain, designated YIM 56035(T), was isolated from the inner tissue of the traditional Chinese medicinal plant Lobelia clavata. The strain stained Gram-positive, was aerobic and exhibited branching, white aerial mycelium and yellowish-brown substrate mycelium. The strain formed spore chains on aerial hyphae. The G+C content of the genomic DNA was 70.3 mol%. On the basis of morphological, physiological, chemotaxonomic and phylogenetic characteristics, strain YIM 56035(T) was assigned to the genus Pseudonocardia. Analysis of 16S rRNA gene sequences showed 98.5, 97.3, 97.3 and 97.1 % similarity to the closely related type strains Pseudonocardia kongjuensis LM 157(T), Pseudonocardia autotrophica IMSNU 20050(T), Pseudonocardia ammonioxydans H9(T) and Pseudonocardia compacta IMSNU 20111(T), respectively. The results of DNA-DNA hybridizations and comparison of some phenotypic characteristics revealed that the strain represents a novel species of the genus Pseudonocardia. The name Pseudonocardia endophytica sp. nov. is proposed, with the type strain YIM 56035(T) (=DSM 44969(T) =CCTCC AA 206026(T) =KCTC 19150(T)).

Streptomyces mayteni sp. nov., a novel actinomycete isolated from a Chinese medicinal plant.

An actinomycete strain, designated YIM 60475(T), was isolated from the roots of Maytenus austroyunnanensis and was characterized by using a polyphasic approach. The strain was determined to belong to the genus Streptomyces, based on its phenotypic and phylogenetic characteristics. The strain produced spiral spore chains on aerial mycelium. The cell wall contained LL-diaminopimelic acid. Whole-cell hydrolysates contained galactose, glucose, and xylose. The phospholipid was type II. The DNA G+C content of the type strain was 73.3 mol%. DNA-DNA hybridization and comparison of physiological and chemical characteristics suggested that strain YIM 60475(T) is a new Streptomyces species, for which the name Streptomyces mayteni sp. nov. is proposed. The type strain is YIM 60475(T) (=CCTCC AA 207005(T) = KCTC 19383(T)).

Glycomyces endophyticus sp. nov., an endophytic actinomycete isolated from the root of Carex baccans Nees.

An actinomycete, designated strain YIM 56134(T), was isolated from the root of a Chinese medicinal plant, Carex baccans Nees, collected from Yunnan, south-west China, and subjected to a polyphasic taxonomic study. An analysis of 16S rRNA gene sequence similarities showed that strain YIM 56134(T) was a member of the genus Glycomyces, being most closely related to Glycomyces algeriensis NRRL B-16327(T) (99.0 % similarity), Glycomyces lechevalierae DSM 44724(T) (99.0 %), Glycomyces rutgersensis IFO 14488(T) (98.9 %) and Glycomyces harbinensis IFO 14487(T) (98.7 %). Strain YIM 56134(T) could be distinguished from other established Glycomyces species on the basis of relatively low sequence similarity (<97 %). Phenotypic and chemotaxonomic data supported the affiliation of this strain to the genus Glycomyces. The results of DNA-DNA hybridization and some physiological and biochemical tests allowed differentiation of the strain from related Glycomyces species. Therefore, strain YIM 56134(T) represents a novel species of the genus Glycomyces, for which the name Glycomyces endophyticus sp. nov. is proposed. The type strain is YIM 56134(T) (=KCTC 19152(T) =DSM 45002(T)).

Saccharopolyspora endophytica sp. nov., an endophytic actinomycete isolated from the root of Maytenus austroyunnanensis.

A Gram-positive, aerobic, non-motile, non-acid-alcohol-fast strain, designated YIM 61095(T), was isolated from the root of Maytenus austroyunnanensis collected from a tropical rainforest of Xishuangbanna in Yunnan Province, south-west China. Strain YIM 61095(T) exhibited chemotaxonomic and morphological characteristics that were consistent with members of the genus Saccharopolyspora. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 61095(T) was a member of the genus Saccharopolyspora and was most closely related to Saccharopolyspora flava AS 4.1520(T) (97.7% sequence similarity). The major fatty acids were iso-C(15:0), iso-C(16:0), iso-C(17:0) and anteiso-C(17:0). The predominant quinone detected was MK-9(H(4)). The DNA G+C content was 66.2 mol%. The phenotypic characteristics and DNA-DNA hybridization relatedness data indicated that strain YIM 61095(T) should be distinguished from Saccharopolyspora flava AS 4.1520(T). On the basis of the evidence presented in this study, strain YIM 61095(T) represents a novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora endophytica sp. nov. is proposed. The type strain is YIM 61095(T) (=KCTC 19397(T)=CCTCC AA 208003(T)).

Rhodococcus cercidiphylli sp. nov., a new endophytic actinobacterium isolated from a Cercidiphyllum japonicum leaf.

An endophytic actinobacterium, designated YIM 65003(T), was isolated from a surface sterilized leaf sample of Cercidiphyllum japonicum collected from Yunnan province, south-west China. The morphological and chemotaxonomic properties of the isolate were typical of members of the genus Rhodococcus. Analysis of the 16S rRNA gene sequence revealed that the isolate was most closely related to Rhodococcus fascians DSM 20669(T) (99.6%) and Rhodococcus yunnanensis YIM 70056(T) (99.0%). DNA-DNA hybridization with the above microorganisms (46.3% and 48.8%, respectively), in combination with differences in the biochemical and physiological properties, suggested that strain YIM 65003(T) should be classified within a novel species of the genus Rhodococcus, for which the name Rhodococcus cercidiphylli sp. nov. is proposed, with YIM 65003(T) (=CCTCC AB 207160(T)=DSM 45141(T)) as the type strain. The 16S rRNA gene sequence of strain YIM 65003(T) has been deposited in GenBank under the accession number EU325542.

Actinomadura alba sp. nov., isolated from soil in Yunnan, China.

A novel actinomycete, strain YIM 45681(T), which was isolated from soil in a suburb of Kunming, Yunnan Province, China, was subjected to phenotypic and genotypic characterization. The micro-organism, which produces short spore chains arranged in spirals on the aerial mycelium, was shown to have meso-diaminopimelic acid in the cell wall. The sugars present in whole-cell hydrolysates were ribose, xylose, galactose, madurose and glucose. The predominant menaquinones were MK-9(H(4)), MK-9(H(6)) and MK-9(H(2)). The phospholipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were iso-C(16 : 1) H, C(17 : 1) omega 8c, 10-methyl C(17 : 0) and C(16 : 0). A comparative analysis of 16S rRNA gene sequences indicated that the organism formed a distinct clade within the evolutionary radiation of the family Thermomonosporaceae, and that it was closely associated with members of the genus Actinomadura. A broad range of phenotypic and genetic data supported the suggestion that this organism represents a novel species of the genus Actinomadura, for which the name Actinomadura alba sp. nov. is proposed, with YIM 45681(T) (=DSM 45045(T) =CCTCC AA206005(T)) as the type strain.

Streptomyces serianimatus sp. nov., isolated from a rhizophere soil.

A novel actinomycete strain, designated YIM 45720(T), was isolated from a Cephalotaxus fortunei rhizophere soil sample collected from Yunnan Province, southwest China. The strain formed well-differentiated aerial and substrate mycelia. Chemotaxonomically, it contained LL-diaminopimelic acid in the cell wall. The cell-wall sugars contained ribose, mannose, and galactose with traces of glucose and xylose. Phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositol. MK-9 (H(8)) was the predominant menaquinone. The major fatty acids (>10%) were iso-C(16:0), iso-C(15:1) and anteiso-C(15:0). The G + C content of the DNA was 70 mol%. Phylogenetic analysis data based on 16S rRNA gene sequence showed that strain YIM 45720(T) formed a distinct branch with the type strain of Streptomyces scabrisporus JCM 11712(T) within the genus Streptomyces. On the basis of the phenotypic and genotypic characteristics, strain YIM 45720(T) (=DSM 41883(T) = CCTCC AA 206006(T)) is proposed as the type strain of a novel species, Streptomyces serianimatus sp. nov.

Kocuria aegyptia sp. nov., a novel actinobacterium isolated from a saline, alkaline desert soil in Egypt.

A coccoid, non-motile actinobacterium, designated strain YIM 70003T, was isolated from a saline, alkaline, desert-soil sample from Egypt. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the organism formed a distinct phyletic line within the genus Kocuria and was most closely related to Kocuria polaris DSM 14382T (98.6 % sequence similarity) and Kocuria rosea DSM 20447T (98.2 %). Chemotaxonomic data, including the Lys-Ala3 peptidoglycan type, the presence of phosphatidylglycerol and diphosphatidylglycerol as the predominant phospholipids, the presence of MK-8(H2) and MK-9(H2) as the major menaquinones, the predominance of fatty acids ai-C(15 : 0) and i-C(15 : 0) and the DNA G+C content, also supported the affiliation of the isolate to the genus Kocuria. The low DNA-DNA relatedness with K. polaris DSM 14382T (56.6 %) and K. rosea DSM 20447T (15.5 %) in combination with phenotypic data show that strain YIM 70003T should be classified as a novel species of the genus Kocuria. The name Kocuria aegyptia sp. nov. is proposed, with strain YIM 70003T (=CCTCC AA203006T = CIP 107966T = KCTC 19010T = DSM 17006T) as the type strain.

Nocardia polyresistens sp. nov.

A novel actinomycete strain YIM 33361(T) was isolated from a soil sample collected from Yunnan, China. Comparative 16S rRNA gene sequencing showed that the strain constituted a distinct subclade within the genus Nocardia, displaying more than 3% sequence divergence from established species. Based on its morphological, chemotaxonomic, phenotypic and genotypic characteristics, strain YIM 33361(T) (=CCTCC AA 204004(T)=KCTC 19027(T)) is proposed as the type strain of a novel species, Nocardia polyresistens sp. nov.

Naxibacter alkalitolerans gen. nov., sp. nov., a novel member of the family 'Oxalobacteraceae' isolated from China.

A taxonomic study was performed on strain YIM 31775(T), which was isolated from a soil sample collected from Yunnan Province, China. The isolate was chemo-organotrophic, aerobic and Gram-negative. Cells were short rods and motile, with one or more polar flagella. Growth temperature and pH ranged from 4 to 55 degrees C and 6.5 to 12.0, respectively; the optimum growth temperature and pH were 28-37 degrees C and 7.0-9.0, respectively. Q-8 was the predominant respiratory lipoquinone. The major fatty acids were C(16 : 1)omega7c (42.4 %) and C(16 : 0) (28.1 %). The DNA G + C content was 62.4 +/ -0.3 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain YIM 31775(T) should be placed within the family 'Oxalobacteraceae', in which it formed a distinct lineage. Based on the high 16S rRNA gene sequence divergence and phenotypic characteristics, it is proposed that strain YIM 31775(T) should be classified as representing a novel member of the family 'Oxalobacteraceae', for which the name Naxibacter alkalitolerans gen. nov., sp. nov. is proposed. The type strain is YIM 31775(T) (= CCTCC AA 204003(T) = KCTC 12194(T)).

Microbacterium halotolerans sp. nov., isolated from a saline soil in the west of China.

A Gram-positive short rod isolated from a saline soil in China was characterized using a polyphasic approach. This actinobacterium grew over a wide salinity range [0-15 % NaCl, 0-20 % KCl and 0-30 % (MgCl2).6H2O (w/v); optimum concentrations for growth were 5 % NaCl, 5-10 % KCl, 10 % (MgCl2).6H2O]. The optimum growth temperature and pH were 28-30 degrees C and 7.0-8.0, respectively. Chemotaxonomic features (peptidoglycan-type B2beta with glycolyl residues; major menaquinones MK-10 and MK-11; predominating iso- and anteiso-branched cellular fatty acids; DNA G+C content 66.5 mol%) placed this organism within the genus Microbacterium. 16S rRNA gene sequence analysis confirmed this classification of the strain, but showed that it was distinct from its nearest neighbours. It formed a separate branch with type strains of the genus Microbacterium, and also shared low sequence similarity with them (<96 %). Based on phenotypic and molecular taxonomic results, it is proposed that the unknown isolate should be classified as a novel species in the genus Microbacterium, for which the name Microbacterium halotolerans sp. nov. is proposed. The type strain is YIM 70130T (=KCTC 19017T=CIP 108071T).

Citricoccus alkalitolerans sp. nov., a novel actinobacterium isolated from a desert soil in Egypt.

An actinobacterium, strain YIM 70010T, which was isolated from a desert soil sample collected in Egypt, was subjected to a polyphasic taxonomy study. The organism was alkalitolerant and its optimum growth occurred at pH 8.0-9.0. The isolate contained chemotaxonomic markers that were characteristic of the genus Citricoccus, i.e. the peptidoglycan type Lys-Gly-Glu (variation A4alpha), the predominant menaquinone MK-9(H2) and a polar lipid profile consisting of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two unknown glycolipids. The major fatty acids were anteiso-C(15 : 0) and iso-C(15 : 0). The G+C content of the genomic DNA was 63.8 mol%. Strain YIM 70010T exhibited a 16S rRNA gene sequence similarity of 99.6 % and DNA-DNA relatedness value of 56 % with Citricoccus muralis DSM 14442T. The phenotypic characteristics and DNA-DNA relatedness data indicate that strain YIM 70010T can be distinguished from C. muralis (DSM 14442T). Therefore, on the basis of the polyphasic taxonomic data presented, a novel species of the genus Citricoccus, Citricoccus alkalitolerans sp. nov. (type strain, YIM 70010)=CCTCC AA 203008T=DSM 15665T=KCTC 19012T) is proposed.