During our investigation on the endophytic fungi of Azadirachta indica, the strain YM 311593 was obtained from the fruit of the plant. The culture extract of the strain showed antifungal activities against four phytopathogenic fungi. Based on the morphological features and phylogenetic definition, the strain YM 311593 was identified as Paraconiothyrium sp. Four xanthones and one anthraquinone were obtained from the extract of the fermentation broth of the strain. They were characterized to be globosuxanthone A (1), vertixanthone (2), hydroxyvertixanthone (3), 3,8-dihydroxy-1-methy1-9H- xanthen-9-one (4), and danthron (5), respectively, by spectroscopic elucidation. Furthermore, the absolute configuration of 1 was deduced by X-ray diffraction analysis. Besides, compound 4 was firstly found from natural sources. The antifungal activities of compounds 1-5 towards four phytopathogens were assayed using broth microdilution method. Among them, globosuxanthone A (1) showed obvious antifungal activity towards Fusarium graminearum, Fusarium solani, and Botrytis cinerea with MIC values of 4, 8, and 16 μg/mL, respectively.
- MeSH
- Ascomycota chemie izolace a purifikace MeSH
- Azadirachta mikrobiologie MeSH
- endofyty chemie izolace a purifikace MeSH
- fungicidy průmyslové izolace a purifikace farmakologie MeSH
- fylogeneze MeSH
- houby účinky léků MeSH
- kultivační média chemie MeSH
- ovoce mikrobiologie MeSH
- xantony izolace a purifikace farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
The citrus black spot (CBS), caused by Phyllosticta citricarpa, is one of the most important citrus diseases in subtropical regions of Africa, Asia, Oceania, and the Americas, and fruits with CBS lesions are still subject to quarantine regulations in the European Union. Despite the high application of fungicides, the disease remains present in the citrus crops of Central and South America. In order to find alternatives to help control CBS and reduce the use of fungicides, we explored the antifungal potential of endophytic actinomycetes isolated from the Brazilian medicinal plant Vochysia divergens found in the Pantanal biome. Two different culture media and temperatures were selected to identify the most efficient conditions for the production of active secondary metabolites. The metabolites produced by strain Microbacterium sp. LGMB471 cultured in SG medium at 36 °C considerably inhibited the development of P. citricarpa. Three isoflavones and five diketopiperazines were identified, and the compounds 7-O-β-D-glucosyl-genistein and 7-O-β-D-glucosyl-daidzein showed high activity against P. citricarpa, with the MIC of 33 μg/mL and inhibited the production of asexual spores of P. citricarpa on leaves and citrus fruits. Compounds that inhibit conidia formation may be a promising alternative to reduce the use of fungicides in the control of CBS lesions, especially in regions where sexual reproduction does not occur, as in the USA. Our data suggest the use of Microbacterium sp. LGMB471 or its metabolites as an ecological alternative to be used in association with the fungicides for the control of CBS disease.
- MeSH
- Actinomycetales chemie MeSH
- Ascomycota účinky léků MeSH
- Citrus mikrobiologie MeSH
- diketopiperaziny izolace a purifikace farmakologie MeSH
- fungicidy průmyslové izolace a purifikace farmakologie MeSH
- isoflavony izolace a purifikace farmakologie MeSH
- kultivační média MeSH
- listy rostlin mikrobiologie MeSH
- mikrobiální testy citlivosti MeSH
- nemoci rostlin mikrobiologie MeSH
- sekundární metabolismus MeSH
- spory hub účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Asie MeSH
- Brazílie MeSH
- Spojené státy americké MeSH
Preparations with elicitation activity were obtained from the mycelium of Leptosphaeria maculans , a fungal pathogen of oilseed rape (Brassica napus). Crude delipidated and deproteinized extract from fungal cell walls induced expression of pathogenesis related gene 1 (PR1), hydrogen peroxide accumulation, and enhanced resistance of B. napus plants toward infection by L. maculans. Elicitation activity significantly decreased after treatment of a crude extract with α- or β-glucanase. Monosaccharide composition analysis of a crude extract purified by ion-exchange chromatography revealed glucose (∼58 mol %), mannose (∼22 mol %), and galactose (∼18 mol %) as the major sugars. FT-IR and NMR spectra confirmed the presence of both carbohydrate and polypeptide components in the purified product. Correlation NMR experiments defined trisaccharide bound to O-3 of serine residue α-D-Glcp-(1→2)-β-D-Galf-(1→6)-α-D-Manp-(1→3)-L-Ser. Terminal α-D-Glcp and (1→6)-β-D-glucan were also detected. The obtained results strongly support the conclusion that these carbohydrates induce defense response in B. napus plants.
- MeSH
- Ascomycota chemie růst a vývoj imunologie MeSH
- Aspergillus niger enzymologie MeSH
- Brassica napus účinky léků imunologie metabolismus mikrobiologie MeSH
- buněčná stěna chemie MeSH
- buněčné extrakty chemie izolace a purifikace farmakologie MeSH
- chemie zemědělská metody MeSH
- down regulace MeSH
- fungální proteiny analýza chemie metabolismus MeSH
- fungicidy průmyslové chemie izolace a purifikace farmakologie MeSH
- glykosidhydrolasy biosyntéza genetika metabolismus MeSH
- glykosidy analýza chemie metabolismus MeSH
- hydrolýza MeSH
- mycelium chemie růst a vývoj imunologie MeSH
- odolnost vůči nemocem účinky léků MeSH
- oligosacharidy analýza chemie metabolismus MeSH
- peptidové fragmenty analýza chemie metabolismus MeSH
- peroxid vodíku metabolismus MeSH
- rostlinné proteiny biosyntéza genetika metabolismus MeSH
- semenáček účinky léků imunologie metabolismus mikrobiologie MeSH
- upregulace účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
