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- Kälvö, David, et al.
(författare)
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Biosynthesis of fomannoxin in the root rotting pathogen Heterobasidion occidentale
- 2012
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Ingår i: Phytochemistry. - : Elsevier BV. - 0031-9422 .- 1873-3700. ; 84, s. 31-39
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Tidskriftsartikel (refereegranskat)abstract
- Fomannoxin is a biologically active benzohydrofuran, which has been suggested to be involved in the pathogenicity of the root rotting fungus Heterobasidion annosum sensu lato. The biosynthesis of fomannoxin was investigated through an isotopic enrichment study utilizing [1-C-13]glucose as metabolic tracer. C-13 NMR spectroscopic analysis revealed the labeling pattern and showed that the isoprene building block originates from the mevalonic acid pathway, whereas the aromatic motif is formed via the shikimic acid route by elimination of pyruvate from chorismic acid. A natural product, 4-hydroxy-3-(3-methylbut-2-enyl)benzaldehyde (1), was isolated and characterized, and was suggested to be a key intermediate in the biosynthesis of fomannoxin and related secondary metabolites previously identified from the H. annosum fungal species complex. (c) 2012 Elsevier Ltd. All rights reserved.
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| 2. |
- Kälvö, David, et al.
(författare)
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Secondary metabolite comparison of the species within the Heterobasidion annosum s.l. complex
- 2014
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Ingår i: Phytochemistry. - : Elsevier BV. - 0031-9422 .- 1873-3700. ; 108, s. 243-251
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Tidskriftsartikel (refereegranskat)abstract
- The metabolite production of the five members of the fungal species complex Heterobasidion annosum s.l., i.e. H. annosum s.s., H. abietinum, H. parviporum, H. occidentale and H. irregulare, was analyzed by LC-HAMS. The five members are described to have differences in host preferences: H. annosum s.s. and H. irregulare are pine infecting species, and H. parviporum, H. occidentale and H. abietinum are non-pine infecting. Principal component analysis (PCA) of the LC-HRMS data showed that samples from the five species could be separated into five groups and in accordance with the differences in host preferences. Twenty-three compounds, important to the observed PCA grouping, were isolated and identified. The main contributor to the separation of the pine infecting species from the non-pine infecting species in PC1 was the benzohydrofuran fomannoxin, which was only detected in the pine infecting species H. annosum s.s. and H. irregulare. These two species were further separated in PC3, and one major contributor here was the sesquiterpene deoxyfomannosin A. The three non-pine infecting species were separated in PC2, by epoxydrimenol that was detected in only two of the species and further in PC4, where a few fomannoxin related compounds were important for the grouping. During the work, three unknown compounds were isolated and described: 3-hydroxy-2-(1,3-dihydroxypropan-2-yl)-2,3-dihydrobenzofuran-5-carbaldehyde, 3-hydroxy-2-(1,2,3-trihydroxypropan-2-yl)-2,3-dihydrobenzofuran-5-carbaldehyde and 3-hydroxy-2,3-dihydrobenzofuran-5-carboxylic acid. (c) 2014 Elsevier Ltd. All rights reserved.
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| 3. |
- Kälvö, David, et al.
(författare)
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Secondary Metabolites from the Root Rot Biocontrol Fungus Phlebiopsis gigantea
- 2018
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Ingår i: Molecules. - : MDPI AG. - 1420-3049. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Three cyclopentanoids (phlebiopsin A C), one glycosylated p-terphenyl (methyl-terfestatin A), and o-orsellinaldehyde were isolated from the biocontrol fungus Phlebiopsis gigantea, and their structures were elucidated by 1D and 2D NMR spectroscopic analysis, as well as by LC-HRMS. The biological activity of the compounds against the root rot fungus Heterobasidion occidentale, as well as against Fusarium oxysporum and Penicillium canescens, was also investigated, but only o-orsellinaldehyde was found to have any antifungal activity in the concentration range tested.
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| 4. |
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| 5. |
- Kälvö, David
(författare)
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Structure and biosynthesis of fungal secondary metabolites : studies of the root rot pathogen Heterobasidion annosum s.l. and the biocontrol fungus Phlebiopsis gigantea
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The root rot pathogen Heterobasidion annosum s.l., i.e. H. abietinum, H. parviporum, H. annosum s.s., H. irregulare and H. occidentale, and the biocontrol fungus Phlebiopsis gigantea were investigated regarding their secondary metabolites. Thirty-three compounds, in total, were identified from H. annosum s.l. by HRMS and NMR, including six new fomannosin related sesquiterpenes (illudolone A and B, illudolactone A and B and deoxyfomannosin A and B), one new fomajorin-type compound and seven previously unreported natural products with fomannoxin related structures. The new fomannosin related compounds were proposed to be intermediates in the biosynthesis of the known phytoxin fomannosin. Fomannoxin is a benzohydrofuran that previously has been suggested to be involved in the pathogenicity of H. annosum s.l. The biosynthesis of fomannoxin was investigated through an isotopic enrichment study utilizing [1-13C]glucose as metabolic tracer. The results showed that fomannoxin is produced by a combination of the MVA pathway and the shikimic acid pathway. The secondary metabolite production of the species within H. annosum s.l. was analyzed by LC-HRMS. Subsequent principal component analysis showed that the samples from the five species grouped in accord with the respective species, preferred host and previously established phylogeny. The biocontrol fungus P. gigantea is used to prevent root rot caused by H. annosum s.l. Its mode of action was studied by investigating the production of secondary metabolites. Five secondary metabolites were isolated and identified by HRMS and NMR, out of which three were new compounds (phlebiopsin A-C), one was a new natural product (methyl-terfestatin A) and one was a known compound (o-orsellinaldehyde). Only o-orsellinaldehyde showed growth inhibiting activity against H. occidentale.
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