Dataset Information

New nematicidal and antimicrobial secondary metabolites from a new species in the new genus, Pseudobambusicola thailandica.

ABSTRACT: During the course of a study on the functional biodiversity of the mycobiota inhabiting rainforests in Thailand, a fungal strain was isolated from a plant sample and shown to represent an undescribed species, as inferred from a combination of morphological and molecular phylogenetic methods. Molecular phylogenetic analyses, based on four DNA loci, revealed a phylogenetic tree with the newly generated sequences clustering in a separate branch, together with members of the Sulcatisporaceae (Pleosporales, Ascomycota). The Thai specimen morphologically resembled Neobambusicola strelitziae in having pycnidial conidiomata with phialidic conidiogenous cells that produce both fusoid-ellipsoid macroconidia and subcylindrical microconidia. However, the new fungus, for which the name Pseudobambusicola thailandica is proposed, differs from N. strelitziae in having conidiomata with well-defined necks, the presence of globose to subglobose thick-walled cells adjacent to conidiomata and the production of chlamydospores in culture. When cultures of P. thailandica, growing on water agar, were confronted with Caenorhabditis elegans nematodes, worms approaching the fungal mycelia were killed. This observation gave rise to a study of its secondary metabolites and six novel and two known compounds were isolated from submerged cultures of P. thailandica. The structures of metabolites 1-6, for which the trivial names thailanones A-F are proposed, were elucidated using a combination of spectral methods, including extensive 1 and 2D NMR analysis and high resolution mass spectrometry. Compounds 4 and 8 showed strong nematicidal and weak antifungal activity, whereas all other tested compounds showed moderate to weak nematicidal activity but no significant effects in the serial dilution assay against various fungi and bacteria. Compounds 1 and 8 also inhibited growth of the pathogenic basidiomycete Phellinus tremulae in a plate diffusion assay.

SUBMITTER: Rupcic Z

PROVIDER: S-EPMC5904430 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Publications

New nematicidal and antimicrobial secondary metabolites from a new species in the new genus, <i>Pseudobambusicola thailandica</i>.

Rupcic Zeljka Z Chepkirui Clara C Hernández-Restrepo Margarita M Crous Pedro W PW Luangsa-Ard Janet Jennifer JJ Stadler Marc M

MycoKeys 20180322 33

During the course of a study on the functional biodiversity of the mycobiota inhabiting rainforests in Thailand, a fungal strain was isolated from a plant sample and shown to represent an undescribed species, as inferred from a combination of morphological and molecular phylogenetic methods. Molecular phylogenetic analyses, based on four DNA loci, revealed a phylogenetic tree with the newly generated sequences clustering in a separate branch, together with members of the Sulcatisporaceae (Pleosp ...[more]

PMID: 29681740

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Project description:Endophytic fungi have been recognized as a potential source of bioactive secondary metabolites. The endophytic Trichoderma species were isolated from Vinca plants (Vinca major, Vinca herbacea, and Vinca minor), found in Iran and screened for antimicrobial and anti-proliferative activity. Based on morphological and phylogenetic analyses, four fungal species were identified: T. asperellum, T. brevicompactum, T. koningiopsis, and T. longibrachiatum. In addition, endophytic fungi bioactivity of methanol and ethyl acetate extracts (7.8-250 ?gml-1) were assessed against a panel of pathogenic fungi and bacteria and IC80 was calculated. Data showed that both methanol and ethyl acetate extracts from all endophytic isolates had significant cytotoxic effects against the model target fungus Pyricularia oryzae. Further research indicated that they had significant antimicrobial bioactivity against the human pathogenic bacteria Staphylococcus aureus and Escherichia coli, and plant pathogenic bacteria Ralstonia solanacearum and Clavibacter michiganensis as well. According to the bioactivity results, crude ethyl acetate extract of T. koningiopsis VM115 isolate was determined for TLC and GC-MS analysis. An antifungal compound was isolated from ethyl acetate extract of T. koningiopsis VM115 based on bioassay guided fractionation. The 1H-NMR and 13C-NMR spectroscopic data showed that the compound was trichodermin, which exhibited strong fungicidal effects against P. oryzae, Aspergillus fumigatus, and Botrytis cinera with MICs of 31.25 ?g ml-1 through in vitro antifungal tests. GC-MS analysis identified six classes of volatile compound produced by T. koningiopsis VM115 (alcohols, esters, pyrones (lactones), acids, furanes and lipids). 6-n-pentyl-6H-pyran-2-one (6PP) was identified as one of the most abundant metabolites in this research. These results indicate that the fungal endophytes from Vinca plants had antibacterial and cytotoxic activities; evidence that endophytes are a good source of biological activity and compounds. This work is the first report of Trichodermin production by T. koningiopsis species.

Dataset Information

New nematicidal and antimicrobial secondary metabolites from a new species in the new genus, Pseudobambusicola thailandica.

Publications

New nematicidal and antimicrobial secondary metabolites from a new species in the new genus, <i>Pseudobambusicola thailandica</i>.

Similar Datasets

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