Juan Cheng

Nocardioides ginkgobilobae sp. nov., an endophytic actinobacterium isolated from the root of the living fossil Ginkgo biloba L.

A Gram-stain-positive, aerobic and yellow actinobacterial strain, designated SYP-A7303T, was isolated from the root of Ginkgo biloba L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-A7303T belongs to the genus Nocardioides. The 16S rRNA gene sequence of strain SYP-A7303T showed highest similarity to Nocardioides marinus CL-DD14T ( = JCM 15615T) (98.3 %) and Nocardioides aquiterrae GW-9T ( = JCM 11813T) (97.1 %), and less than 96.9 % to the type strains of other species of the genus Nocardioides. Strain SYP-A7303T grew optimally at 28 °C, pH 7.0 and in the absence of NaCl. It contained ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, with mannose, ribose, rhamnose, glucose and galactose as whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown lipid. The menaquinone was MK-8(H4) and the predominant cellular fatty acids were iso-C16 : 0, C18 : 1ω9c and C17 : 1ω8c. The DNA G+C content was 72 mol%. Mean DNA-DNA relatedness values between strain SYP-A7303T and the closely related strains N. marinus JCM 15615T and N. aquiterrae JCM 11813T were 62.5 ± 2.4 and 56.5 ± 3.5 %, respectively. Based on the morphological, physiological, biochemical and chemotaxonomic characteristics presented in this study, strain SYP-A7303T represents a novel species of the genus Nocardioides, for which the name Nocardioides ginkgobilobae sp. nov. is proposed. The type strain is SYP-A7303T ( = DSM 100492T = KCTC 39594T).

Luteimonas notoginsengisoli sp. nov., isolated from rhizosphere soil.

A Gram-staining-negative, yellow-pigmented strain, designated SYP-B804T, was isolated from the rhizosphere of Panax notoginseng. The strain was rod-shaped with a single polar flagellum. The optimum temperature and pH required for growth of the strain were 28-32 °C and pH 7-8, respectively. 16S rRNA gene sequence analysis indicated that strain SYP-B804T showed highest 16S rRNA gene sequence similarity with Luteimonas mephitis DSM 12574T (98.0 %). However, the DNA-DNA relatedness value between them (38.1 ± 0.6 %) was less than the threshold value for the delineation of genomic species. Ubiquinone-8 (Q-8) was the predominant quinone. The major fatty acids were iso-C15 : 0 and iso-C17 : 1ω9c. The major polar lipids of the strain were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The G+C content of the genomic DNA was 71 %. On the basis of phenotypic, chemotaxonomic and molecular characteristics, strain SYP-B804T merits recognition as a representative of a novel species of the genus Luteimonas, for which the name Luteimonas notoginsengisoli sp. nov. is proposed, with SYP-B804T ( = KCTC 42211T = JCM 30329T) as the type strain.

Arthrobacter ginkgonis sp. nov., an actinomycete isolated from rhizosphere of Ginkgo biloba L.

A Gram-stain-positive, aerobic actinobacterial strain (designated SYP-A7299T), which displayed a rod-coccus growth lifecycle, was isolated from the rhizosphere of Ginkgo biloba L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-A7299T belongs to the genus Arthrobacter and is most closely related to Arthrobacter halodurans JSM 078085T (97.4 % 16S rRNA gene sequence similarity). The DNA-DNA relatedness value between strain SYP-A7299T and A. halodurans JSM 078085T was 37 % ±2.9. The cell-wall peptidoglycan was A4α, and glucose and galactose were whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two glycolipids and an unknown polar lipid. The major menaquinone were MK-8(H2) (72 %) and MK-9(H2) (28 %), and the predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 0. The DNA G+C content was 68.9 mol%. Based on the morphological, physiological, biochemical and chemotaxonomic characters presented in this study, strain SYP-A7299T represents a novel species of the genus Arthrobacter, for which the name Arthrobacter ginkgonis sp. nov. is proposed. The type strain is SYP-A7299T (=DSM 100491T=KCTC 39 592T).

Leifsonia flava sp. nov., a novel actinobacterium isolated from the rhizosphere of Aquilegia viridiflora

SYP-B2174T is a yellow-pigmented, Gram-positive, non-motile, and rod-shaped actinobacterium isolated from the rhizospheric soil of Aquilegia viridiflora Pall. collected from the Xinjiang uygur autonomous region of China. The strain’s growth temperature ranges from 1 to 35°C, with an optimal growth being observed at 28°C. Growth occurs from 0 to 5% NaCl and at pH 6–8, with optimal growth being observed in 1% NaCl at pH 7. Comparative 16S rRNA gene sequence-based phylogenetic analysis placed the strain in a clade with the species Leifsonia kafniensis JCM 17021T and Leifsonia psychrotolerans DSM 22824T with similarities of 97.8 and 97.6%, respectively. The DNA-DNA hybridization values of the strain SYP-B2174T to its closest phylogenetic neighbors were significantly lower than 35.7%. The strain was identified as a novel species of the genus Leifsonia judging by the coryneform morphology, peptidoglycans based upon 2,4-diaminobutyric acid, principal phospholipids phosphatidylglycerol and diphosphatidylglycerol, major menaquinone MK-11, predominant fatty acids of anteiso-C15:0, anteiso-C17:0, and iso-C16:0, and a DNA G + C base composition of 68.7 mol%, for which the name Leifsonia flava sp. nov. is proposed. The type strain is SYP-B2174T (= CGMCC 1.15856T = DSM 105144T = KCTC 39963T).

Verruconis panacis sp. nov., an endophyte isolated from Panax notoginseng

An endophytic strain (designated as strain SYPF 8337T) was isolated from the root of 3-year-old Panax notoginseng in Yunnan province of China. Strain SYPF 8337T grew slowly and formed pale brown to brown colonies. Phylogenetic analyses indicated that strain SYPF 8337T was placed in the Verruconis clade. Different from other Verruconis species, strain SYPF 8337T produced four-cell conidia. Furthermore, strain SYPF 8337T is the first fungus isolated as an endophyte of P. notoginseng in the genus Verruconis. Combined with the morphology and molecular analyses, a new species named Verruconis panacis sp. nov. is proposed.

Flavobacterium artemisiae sp. nov., isolated from the rhizosphere of Artemisia annua L. and emended descriptions of Flavobacterium compostarboris and Flavobacterium procerum

A Gram-stain-negative, strictly aerobic, yellow-coloured, motile by gliding and elongated rod-shaped bacterial strain, designated SYP-B1015T, was isolated from the rhizosphere of Artemisia annua L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-B1015T belonged to the genus Flavobacterium and had highest 16S rRNA gene sequence similarity to Flavobacterium compostarboris JCM 16527T (98.1 %) and Flavobacterium procerum JCM 30113T (97.2 %). The predominant respiratory quinone for the strain was MK-6, and the major cellular fatty acids were iso-C15 : 0, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. The polar lipid profile contained phosphatidylethanolamine as a major compound. The DNA G+C content of strain SYP-B1015T was 33.5 mol%. The DNA-DNA relatedness values between strain SYP-B1015T and F. compostarboris JCM 16527T and F. procerum JCM 30113T were 56.5±0.4 and 48.9±1.2 %, respectively. Combining the data from morphological, physiological, biochemical and chemotaxonomic characterizations presented in this study, strain SYP-B1015T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium artemisiae sp. nov. is proposed. The type strain is SYP-B1015T (=CGMCC 1.16115T=KCTC 62025T).

An endophytic Fungi of Ginkgo biloba L. produces antimicrobial metabolites as potential inhibitors of FtsZ of Staphylococcus aureus

A total of 58 fungal isolates, belonging to 24 genera, were obtained from the leaves, stems and roots of Ginkgo biloba L.. Among them, one endophytic fungal strain, Penicillium cataractum SYPF 7131, displayed the strongest antibacterial activity. Four new compounds (1-4) were isolated from the strain fermentation broth together with four known compounds (5-8). These structures were determined on the basis of 1D and 2D NMR and [Rh2(OCOCF3)4]-induced electronic circular dichroism (ECD) spectroscopic analyses. All the isolated compounds were screened for their in vitro antimicrobial activities. Compound 3 and 4 showed moderate inhibitory activity against Staphylococcus aureus. Compound 7 exhibited significant inhibitory activity against S. aureus with MIC value of 10 μg/mL. Further, the in silico molecular docking studies of the active compounds was used to explore the binding interactions with the active site of filamentous temperature-sensitive protein Z (FtsZ) from Staphylococcus aureus. The docking results revealed that compounds 3, 4 and 7 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ from S. aureus validating the observed antimicrobial activity. Based on antimicrobial activities and docking studies, compounds 3, 4 and 7 were identified as promising antimicrobial lead molecules.

Bacillus notoginsengisoli sp. nov., a novel bacterium isolated from the rhizosphere of Panax notoginseng

A Gram-stain-positive, rod-shaped, motile bacterium designated as SYP-B691T was isolated from rhizospheric soil of Panax notoginseng. Phylogenetic analysis indicated that SYP-B691T clearly represented a member of the genus Bacillus and showed 16S rRNA gene similarity lower than 97.0 % with the type strains of species of the genus Bacillus, which indicates that it should be considered as a candidate novel species within this genus. The optimum growth of the strain was found to occur at 37 °C and pH 7.0-9.0. The genomic DNA G+C content was determined to be 45.2 mol%. It contained meso-2,6-diaminopimelic acid in the cell-wall peptidoglycan. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unknown phospholipid. MK-7 was the only menaquinone identified. The major cellular fatty acids of SYP-B691T were identified as iso-C15 : 0 and anteiso-C15 : 0. On the basis of phenotypic, chemotaxonomic and phylogenetic characteristics, SYP-B691T merits recognition as a representative of a novel species of the genus Bacillus, for which the name Bacillus notoginsengisoli sp. nov. is proposed, with SYP-B691T(=DSM 29196T=JCM 30743T) as the type strain.