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Variation in type A trichothecene production and trichothecene biosynthetic genes in Fusarium goolgardi from natural ecosystems of Australia.

Rocha LO, Laurence MH, Proctor RH, McCormick SP, Summerell BA, Liew EC - Toxins (Basel) (2015)

Bottom Line: Other isolates (50%) produced only DAS (DAS chemotype).However, the relationships of F. goolgardi to the other species varied depending on whether phylogenies were inferred from RPB1 and RPB2, the 12-gene TRI cluster, the two-gene TRI1-TRI16 locus, or the single-gene TRI101 locus.Sequence analysis indicated that TRI1 and TRI16 are functional in F. goolgardi isolates with the DAS-NEO-T2 chemotype, but non-functional in isolates with DAS chemotype due to the presence of premature stop codons caused by a point mutation.

View Article: PubMed Central - PubMed

Affiliation: The Royal Botanic Gardens and Domain Trust, Mrs Macquaries Rd, Sydney, NSW 2000, Australia. lilianarocha@usp.br.

ABSTRACT
Fusarium goolgardi, isolated from the grass tree Xanthorrhoea glauca in natural ecosystems of Australia, is closely related to fusaria that produce a subgroup of trichothecene (type A) mycotoxins that lack a carbonyl group at carbon atom 8 (C-8). Mass spectrometric analysis revealed that F. goolgardi isolates produce type A trichothecenes, but exhibited one of two chemotypes. Some isolates (50%) produced multiple type A trichothecenes, including 4,15-diacetoxyscirpenol (DAS), neosolaniol (NEO), 8-acetylneosolaniol (Ac-NEO) and T-2 toxin (DAS-NEO-T2 chemotype). Other isolates (50%) produced only DAS (DAS chemotype). In the phylogenies inferred from DNA sequences of genes encoding the RNA polymerase II largest (RPB1) and second largest (RPB2) subunits as well as the trichothecene biosynthetic genes (TRI), F. goolgardi isolates were resolved as a monophyletic clade, distinct from other type A trichothecene-producing species. However, the relationships of F. goolgardi to the other species varied depending on whether phylogenies were inferred from RPB1 and RPB2, the 12-gene TRI cluster, the two-gene TRI1-TRI16 locus, or the single-gene TRI101 locus. Phylogenies based on different TRI loci resolved isolates with different chemotypes into distinct clades, even though only the TRI1-TRI16 locus is responsible for structural variation at C-8. Sequence analysis indicated that TRI1 and TRI16 are functional in F. goolgardi isolates with the DAS-NEO-T2 chemotype, but non-functional in isolates with DAS chemotype due to the presence of premature stop codons caused by a point mutation.

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Representative Gas chromatography-mass spectrometry (GC/MS) data generated of F. goolgardi culture extracts. (a) GC/MS of the F. goolgardi RBG5420, representing 4,15-diacetoxyscirpenol-neosolaniol-T-2 toxin (DAS-NEO-T2) chemotype; (b) GC/MS of the F. goolgardi RBG5421, representing DAS chemotype. * indicates putative 8-acylneosolaniol with MS spectrum similar to those of 8-acetylneosolaniol, 8-propionylneosolaniol, 8-butyrylneosolaniol and T-2 toxin (= 8-isovalerylneosolaniol), i.e., m/z 121 base peak, and m/z 364 and 382 ions).
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toxins-07-04577-f001: Representative Gas chromatography-mass spectrometry (GC/MS) data generated of F. goolgardi culture extracts. (a) GC/MS of the F. goolgardi RBG5420, representing 4,15-diacetoxyscirpenol-neosolaniol-T-2 toxin (DAS-NEO-T2) chemotype; (b) GC/MS of the F. goolgardi RBG5421, representing DAS chemotype. * indicates putative 8-acylneosolaniol with MS spectrum similar to those of 8-acetylneosolaniol, 8-propionylneosolaniol, 8-butyrylneosolaniol and T-2 toxin (= 8-isovalerylneosolaniol), i.e., m/z 121 base peak, and m/z 364 and 382 ions).

Mentions: GC-MS analysis revealed the presence of trichothecenes in GYEP culture extracts of all F. goolgardi strains examined. The analysis indicated that strains RBG5411, RBG5417, RBG5419, and RBG5420 produced the type A trichothecenes DAS, NEO, 8-acetylneosolaniol and T-2 toxin (=8-isovaleryl neosolaniol) (DAS-NEO-T2 chemotype), whereas isolates RBG5421, RBG5422, RBG6914, and RBG6915 produced only DAS (DAS chemotype) (Figure 1). Neither trichothecenes with a carbonyl group at C-8 (i.e., type B trichothecenes such as deoxynivalenol or nivalenol) nor HT-2 toxin were detected in cultures of any of the F. goolgardi isolates. The four isolates with the DAS-NEO-T2 chemotype were from the Bungonia, Khancoban or Tumut region, whereas the four isolates with the DAS chemotype were all from the Yass region (Table S1). Isolates with the DAS-NEO-T2 chemotype also produced 8-propionylneosolaniol, 8-butyrylneosolaniol, and an additional metabolite, which was another type A 8-acylneosolaniol derivative. The other Fusarium species used in this study, including F. palustre, produced DAS, NEO, Ac-NEO, and T-2 toxin (data not shown).


Variation in type A trichothecene production and trichothecene biosynthetic genes in Fusarium goolgardi from natural ecosystems of Australia.

Rocha LO, Laurence MH, Proctor RH, McCormick SP, Summerell BA, Liew EC - Toxins (Basel) (2015)

Representative Gas chromatography-mass spectrometry (GC/MS) data generated of F. goolgardi culture extracts. (a) GC/MS of the F. goolgardi RBG5420, representing 4,15-diacetoxyscirpenol-neosolaniol-T-2 toxin (DAS-NEO-T2) chemotype; (b) GC/MS of the F. goolgardi RBG5421, representing DAS chemotype. * indicates putative 8-acylneosolaniol with MS spectrum similar to those of 8-acetylneosolaniol, 8-propionylneosolaniol, 8-butyrylneosolaniol and T-2 toxin (= 8-isovalerylneosolaniol), i.e., m/z 121 base peak, and m/z 364 and 382 ions).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4663521&req=5

toxins-07-04577-f001: Representative Gas chromatography-mass spectrometry (GC/MS) data generated of F. goolgardi culture extracts. (a) GC/MS of the F. goolgardi RBG5420, representing 4,15-diacetoxyscirpenol-neosolaniol-T-2 toxin (DAS-NEO-T2) chemotype; (b) GC/MS of the F. goolgardi RBG5421, representing DAS chemotype. * indicates putative 8-acylneosolaniol with MS spectrum similar to those of 8-acetylneosolaniol, 8-propionylneosolaniol, 8-butyrylneosolaniol and T-2 toxin (= 8-isovalerylneosolaniol), i.e., m/z 121 base peak, and m/z 364 and 382 ions).
Mentions: GC-MS analysis revealed the presence of trichothecenes in GYEP culture extracts of all F. goolgardi strains examined. The analysis indicated that strains RBG5411, RBG5417, RBG5419, and RBG5420 produced the type A trichothecenes DAS, NEO, 8-acetylneosolaniol and T-2 toxin (=8-isovaleryl neosolaniol) (DAS-NEO-T2 chemotype), whereas isolates RBG5421, RBG5422, RBG6914, and RBG6915 produced only DAS (DAS chemotype) (Figure 1). Neither trichothecenes with a carbonyl group at C-8 (i.e., type B trichothecenes such as deoxynivalenol or nivalenol) nor HT-2 toxin were detected in cultures of any of the F. goolgardi isolates. The four isolates with the DAS-NEO-T2 chemotype were from the Bungonia, Khancoban or Tumut region, whereas the four isolates with the DAS chemotype were all from the Yass region (Table S1). Isolates with the DAS-NEO-T2 chemotype also produced 8-propionylneosolaniol, 8-butyrylneosolaniol, and an additional metabolite, which was another type A 8-acylneosolaniol derivative. The other Fusarium species used in this study, including F. palustre, produced DAS, NEO, Ac-NEO, and T-2 toxin (data not shown).

Bottom Line: Other isolates (50%) produced only DAS (DAS chemotype).However, the relationships of F. goolgardi to the other species varied depending on whether phylogenies were inferred from RPB1 and RPB2, the 12-gene TRI cluster, the two-gene TRI1-TRI16 locus, or the single-gene TRI101 locus.Sequence analysis indicated that TRI1 and TRI16 are functional in F. goolgardi isolates with the DAS-NEO-T2 chemotype, but non-functional in isolates with DAS chemotype due to the presence of premature stop codons caused by a point mutation.

View Article: PubMed Central - PubMed

Affiliation: The Royal Botanic Gardens and Domain Trust, Mrs Macquaries Rd, Sydney, NSW 2000, Australia. lilianarocha@usp.br.

ABSTRACT
Fusarium goolgardi, isolated from the grass tree Xanthorrhoea glauca in natural ecosystems of Australia, is closely related to fusaria that produce a subgroup of trichothecene (type A) mycotoxins that lack a carbonyl group at carbon atom 8 (C-8). Mass spectrometric analysis revealed that F. goolgardi isolates produce type A trichothecenes, but exhibited one of two chemotypes. Some isolates (50%) produced multiple type A trichothecenes, including 4,15-diacetoxyscirpenol (DAS), neosolaniol (NEO), 8-acetylneosolaniol (Ac-NEO) and T-2 toxin (DAS-NEO-T2 chemotype). Other isolates (50%) produced only DAS (DAS chemotype). In the phylogenies inferred from DNA sequences of genes encoding the RNA polymerase II largest (RPB1) and second largest (RPB2) subunits as well as the trichothecene biosynthetic genes (TRI), F. goolgardi isolates were resolved as a monophyletic clade, distinct from other type A trichothecene-producing species. However, the relationships of F. goolgardi to the other species varied depending on whether phylogenies were inferred from RPB1 and RPB2, the 12-gene TRI cluster, the two-gene TRI1-TRI16 locus, or the single-gene TRI101 locus. Phylogenies based on different TRI loci resolved isolates with different chemotypes into distinct clades, even though only the TRI1-TRI16 locus is responsible for structural variation at C-8. Sequence analysis indicated that TRI1 and TRI16 are functional in F. goolgardi isolates with the DAS-NEO-T2 chemotype, but non-functional in isolates with DAS chemotype due to the presence of premature stop codons caused by a point mutation.

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Related in: MedlinePlus