The complete genome sequence of Bacillus velezensis 9912D reveals its biocontrol mechanism as a novel commercial biological fungicide agent.

A Bacillus sp. 9912 mutant, 9912D, was approved as a new biological fungicide agent by the Ministry of Agriculture of the People's Republic of China in 2016 owing to its excellent inhibitory effect on various plant pathogens and being environment-friendly. Here, we present the genome of 9912D with a circular chromosome having 4436 coding DNA sequences (CDSs), and a circular plasmid encoding 59 CDSs. This strain was finally designated as Bacillus velezensis based on phylogenomic analyses. Genome analysis revealed a total of 19 candidate gene clusters involved in secondary metabolite biosynthesis, including potential new type II lantibiotics. The absence of fengycin biosynthetic gene cluster is noteworthy. Our data offer insights into the genetic, biological and physiological characteristics of this strain and aid in deeper understanding of its biocontrol mechanism.

Nocardiopsis oceani sp. nov. and Nocardiopsis nanhaiensis sp. nov., actinomycetes isolated from marine sediment of the South China Sea.

Two actinomycete strains, designated 10A08AT and 10A08BT, were isolated from marine sediment samples of the South China Sea and their taxonomic positions were determined by a polyphasic approach. The two Gram-stain-positive, aerobic strains produced branched substrate mycelium and aerial hyphae, and no diffusible pigment was produced in the media tested. At maturity, spore chains were formed on aerial hyphae and all mycelium fragmented with age. Whole-cell hydrolysates of both strains contained meso-diaminopimelic acid and no diagnostic sugars. Their predominant menaquinones (>10 %) were MK-9(H4), MK-9(H6) and MK-10(H6) for strain 10A08AT and MK-9(H4), MK-9(H6), MK-10(H4) and MK-10(H6) for strain 10A08BT. The polar lipids detected from the two strains were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and unknown phosphoglycolipids and phospholipids. The major fatty acids (>10 %) of both strains were iso-C16 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B). The genomic DNA G+C contents of strains 10A08AT and 10A08BT were 70.9 and 71.6 mol%, respectively. On the basis of 16S rRNA gene sequence similarities, the two strains were shown to be most closely related to species of the genus Nocardiopsis. DNA­DNA hybridization relatedness values of < 70 % between these two isolates and their closest neighbour, Nocardiopsis terrae YIM 90022T, and between the two strains supported the conclusion that they represent two novel species. Based on phylogenetic analysis and phenotypic and genotypic data, it is concluded that the two isolates belong to the genus Nocardiopsis, and the names Nocardiopsis oceani sp. nov. (type strain 10A08AT = DSM 45931T = BCRC 16951T) and Nocardiopsis nanhaiensis sp. nov. (type strain 10A08BT = CGMCC 47227T = BCRC 16952T) are proposed.

Draft genome sequence of the novel strain Pseudomonas sp. 10B238 with potential ability to produce antibiotics from deep-sea sediment.

Pseudomonas sp. 10B238 was a putatively novel species of Pseudomonas, isolated from a deep-sea sediment of the South China Sea, which had the genetic potential to produce secondary metabolites related to nonribosomal peptides (NRPs), as well as showed moderate antimicrobial activities. Here we report a high quality draft genome of Pseudomonas sp. 10B238, which comprises 4,933,052bp with the G+C content of 60.23%. A total of 11 potential secondary metabolite biosynthetic gene clusters were predicted, including a NRP for new peptide siderophore. And many anaerobic respiratory terminal enzymes were found for life in deep-sea environments. Our results may provide insights into biosynthetic pathway for antimicrobial bioactive compounds and be helpful to understand the physiological characteristic of this species.

Streptomyces bohaiensis sp. nov., a novel actinomycete isolated from Scomberomorus niphonius in the Bohai Sea.

A novel actinomycete strain, designated 11A07(T), was isolated from young Scomberomorus niphonius in the Bohai Sea. Basic local alignment search tool analyses showed that this isolate had the highest 16S rRNA gene sequence similarity of 97.41% with Streptomyces rimosus subsp. paromomycinus DSM 41429(T). Phylogenetic tree revealed that strain 11A07(T) formed a distinct lineage clustered with Streptomyces panacagri Gsoil 519(T), Streptomyces sodiiphilus YIM 80305(T) and Streptomyces albus subsp. albus NRRL B-2365(T) having similarities of 97.30%, 97.10% and 96.83%, respectively. Multilocus sequence analysis further demonstrated that the new isolate was different from the selected representatives of Streptomyces as a separate phylogenetic line. Strain 11A07(T) produced straight or rectiflexibile spore chains with smooth surface, white aerial mycelia and brown diffusible pigments on international streptomyces project 2 medium. Maximum tolerated NaCl concentration for growth was 11.0%. Whole-cell sugars were mannose, ribose, glucose, galactose and xylose. The predominant menaquinones were MK-9(H2), MK-9(H4) and MK-9 (H6). The fatty-acid profile contained iso-C16:0, C18:0 10-methyl (tuberculostearic acid) and anteiso-C17:0 as the major compositions. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and an unknown phospholipid. The G+C content of the genomic DNA was 71.4 mol%. These morphological, phenotypic and chemotaxonomic properties showed that strain 11A07(T) could be readily distinguished from the most closely related members of the genus Streptomyces. Thus, based on the polyphasic taxonomic data, strain 11A07(T) (=JCM 19630(T)=CCTCC AA 2013020(T)=KCTC 29263(T)) represents a novel species within the genus Streptomyces, for which the name Streptomyces bohaiensis sp. nov. is proposed.

Identification and characterization of the antifungal substances of a novel Streptomyces cavourensis NA4.

A new actinomycete strain NA4 was isolated from a deep-sea sediment collected from the South China Sea and showed promising antifungal activities against soilborne fungal pathogens. It was identified as Streptomyces cavourensis by morphological, physiological, and phylogenetic analyses based on its 16S rRNA gene sequence. The main antifungal components were isolated and identified from the fermentation culture as bafilomycins B1 and C1. These compounds exhibited significant antifungal activities and a broad antifungal spectrum. The results suggest that the Streptomyces cavourensis NA4 and bafilomycins B1 and C1 could be used as potential biocontrol agents for soilborne fungal diseases of plants.

Structure determination of two new indole-diterpenoids from Penicillium sp. CM-7 by NMR spectroscopy.

Two new indole-diterpenoids 4b-deoxy-1'-O-acetylpaxilline (1) and 4b-deoxypenijanthine A (2) were isolated from the fermentation broth and the mycelia of the soil fungus Penicillium sp. CM-7, along with three known structurally related compounds, 1'-O-acetylpaxilline (3), paspaline (4) and 3-deoxo-4b-deoxypaxilline (5). The structures of compounds 1 and 2 were elucidated by extensive spectroscopic methods, especially 2D NMR, and their absolute configurations were suggested on the basis of the circular dichroism spectral analysis and the NOESY data.

Polyketides from the halotolerant fungus Myrothecium sp. GS-17.

Two new polyketides, myrothecol (1) and 5-hydroxy-3-methyl-4-(1-hydroxylethyl)-furan-2(5H)-one (2), were isolated from the fermentation broth of the halotolerant fungus Myrothecium sp. GS-17 along with three known compounds, 5-hydroxyl-3-[(1S)-1-hydroxyethyl]-4-methylfuran-2(5H)-one (3), 3,5-dimethyl-4- hydroxylmethyl-5-methoxyfuran-2(5H)-one (4), and 3,5-dimethyl-4-hydroxymethyl-5- hydroxyfuran-2(5H)-one (5). Compound 1 is the first natural occurring polyketide with a unique furylisobenzofuran skeleton. The structures of these compounds were established via extensive spectroscopic analyses including 1D-, 2D-NMR, HRESI-MS, and crystal X-ray diffraction analysis.

New spirotetronate antibiotics, lobophorins H and I, from a South China Sea-derived Streptomyces sp. 12A35.

Strain 12A35 was isolated from a deep-sea sediment collected from the South China Sea and showed promising antibacterial activities. It was identified as Streptomyces sp. by the 16S rDNA sequence analysis. Bioassay-guided fractionation using HP20 adsorption, flash chromatography over silica gel and octadecylsilyl (ODS) and semi-preparative HPLC, led to the isolation and purification of five metabolites from the fermentation culture of 12A35. Two new spirotetronate antibiotics, lobophorins H (1) and I (2), along with three known analogues, O-ß-kijanosyl-(1→17)-kijanolide (3), lobophorins B (4) and F (5) were characterized by 1D, 2D-NMR and MS data. These compounds exhibited significant inhibitory activities against Bacillus subtilis. Compounds 1 and 5 exhibited moderate activities against Staphylococcus aureus. In particular, the new compound lobophorin H (1) showed similar antibacterial activities against B. subtilis CMCC63501 to ampicillin.

Description of Streptomonospora sediminis sp. nov. and Streptomonospora nanhaiensis sp. nov., and reclassification of Nocardiopsis arabia Hozzein & Goodfellow 2008 as Streptomonospora arabica comb. nov. and emended description of the genus Streptomonospora.

Two actinomycete strains isolated from marine sediment samples, designated YIM M11335(T) (from the Indian Ocean) and 12A09(T) (from the South China Sea), were obtained and examined by a polyphasic approach. The two Gram-staining-positive, aerobic strains produced branched substrate mycelia and aerial hyphae that were not fragmented, and no diffusible pigment was produced on the media tested. At maturity, spore chains and single spores were formed on aerial hyphae and substrate mycelium, respectively. Whole-organism hydrolysates of both strains contained meso-diaminopimelic acid and the diagnostic sugars glucose and galactose. Their predominant menaquinones were MK-10(H4), MK-10(H6), MK-11(H4), MK-11(H6) and MK-11(H8) for strain YIM 11335(T) and MK-10(H4), MK-10(H6), MK-11(H4), MK-11(H6) and MK-11(H8) for strain 12A09(T). The polar lipids detected in the two strains were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol, phosphatidylcholine, an unknown phosphoglycolipid and several unknown glycolipids, phospholipids and polar lipids. The major fatty acids (>10%) were iso-C16 : 0 and C16:0 for strain YIM 11335(T) and iso-C16:0 for strain 12A09(T). The G+C contents of the genomic DNA of strains YIM 11335(T) and 12A09(T) were 70.7% and 74.4%, respectively. DNA-DNA hybridization relatedness values of these two isolates with the type strains Nocardiopsis arabia DSM 45083(T) and Streptomonospora halophila YIM 91355(T) supported the hypothesis they are representatives of two different species. Based on phylogenetic analysis, phenotypic and genotypic data, it is concluded that the two isolates belong to the genus Streptomonospora of the family Nocardiopsaceae and that the type strain of N. arabia should be reclassified as a representative of Streptomonospora arabica comb. nov. The names proposed for the two novel species are Streptomonospora sediminis sp. nov. (type strain YIM M11335(T) = DSM 45723(T) = CCTCC AB 2012051(T)) and Streptomonospora nanhaiensis sp. nov. (type strain 12A09(T) = KCTC 29145(T) = CCTCC AB 2013140(T)), respectively. An emended description of the genus Streptomonospora is also proposed in the light of the new data.

Structure determination of two new trichothecenes from a halotolerant fungus Myrothecium sp. GS-17 by NMR spectroscopy.

Two new trichothecenes, named 8α-hydroxyroridin H and myrothecin A, along with six known compounds, 8α-acetoxy roridin H, isororidin K, verrucarin A, verrucarin J, verrucarin L and 8α-acetoxy verrucarin L, were isolated from the fermentation broth of a halotolerant fungus Myrothecium sp. GS-17, which was separated from the soil sample of a salina. Structure elucidation and NMR signal assignments were achieved on the basis of spectroscopy. In addition, compounds 1 and 2 were active against plant pathogenic fungi Rhizoctonia solani and Fusarium oxysporum.