endophytic Coniochaeta velutina producing broad spectrum antimycotics

• Published in: The journal of microbiology 2015, 53(6), , pp.390-397
• Main Authors: Xie, Jie, Strobel, Gary A, Feng, Tao, Ren, Huishuang, Mends, Morgan T, Zhou, Zeyang, Geary, Brad
• Format: Article
• Language: English
• Subjects: Antifungal Agents - chemistry; Antifungal Agents - isolation & purification; Antifungal Agents - metabolism; Antifungal Agents - pharmacology; Ascomycota - classification; Ascomycota - genetics; Ascomycota - isolation & purification; Ascomycota - metabolism; bioactive properties; Biomedical and Life Sciences; Chromatography, Liquid; Cluster Analysis; Coniochaeta; Cytosol - chemistry; DNA, Fungal - chemistry; DNA, Fungal - genetics; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; DNA, Ribosomal Spacer - chemistry; DNA, Ribosomal Spacer - genetics; emodin; endophytes; Endophytes - classification; Endophytes - genetics; Endophytes - isolation & purification; Endophytes - metabolism; Fungi; glycosides; high performance liquid chromatography; Life Sciences; Liquid chromatography; Mass Spectrometry; Microbial Sensitivity Tests; Microbiological Techniques; Microbiology; Microorganisms; minimum inhibitory concentration; Molecular Sequence Data; Morphology; nucleotide sequences; Pathogens; Phylogenetics; Phylogeny; Phytophthora palmivora; plant pathogens; Plant Stems - microbiology; Pythium - drug effects; Pythium ultimum; Quinones - analysis; rain forests; Rainforests; ribosomal DNA; RNA, Ribosomal, 18S - genetics; RNA, Ribosomal, 5.8S - genetics; Scanning electron microscopy; Sclerotinia sclerotiorum; Seeds; Sequence Analysis, DNA; Silica; Solvent extraction; solvents; Tsuga - microbiology; Tsuga heterophylla; Verticillium dahliae; 생물학
• ISSN: 1225-8873; 1976-3794
• DOI: 10.1007/s12275-015-5105-5

An endophyte (PC27-5) was isolated from stem tissue of Western hemlock (Tsuga heterophylla) in a Pacific Northwest temperate rainforest. Phylogenetic analyses, based on ITS-5.8S rDNA and 18S rDNA sequence data, combined with cultural and morphological analysis showed that endophyte PC27-5 exhibited all characteristics of a fungus identical to Coniochaeta velutina. Furthermore, wide spectrum antimycotics were produced by this endophyte that were active against such plant pathogens as Sclerotinia sclerotiorum, Pythium ultimum, and Verticillium dahliae and lethal to Phythophthora cinnamomi, Pythium ultimum, and Phytophthora palmivora in plate tests. The bioactive components were purified through organic solvent extraction, followed by silica column chromatography, and finally preparative HPLC. The minimum inhibitory concentration of the active fraction to Pythium ultimum, which was gained from preparative HPLC, was 11 μg/ml. UPLC-HRMS analysis showed there were two similar components in the antimycotic fraction. Their molecular formulae were established as C₃₀H₂₂O₁₁(compound I) and C₃₀H₂₂O₁₀(compound II) respectively, and preliminary spectral results indicate that they are anthroquinone glycosides. Other non–biologically active compounds were identified in culture fluids of this fungus by spectral means as emodin and chrysophanol - anthroquinone derivatives. This is the first report that Coniochaeta velutina as an endophyte produces bioactive antifungal components.