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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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Related in: MedlinePlus

Maximum parsimony trees inferred in this study. (a) One of two most-parsimonious trees for the combined RPB1 and RPB2 data sets, including 22 isolates with F. sambucinum as the outgroup; (b) The most parsimonious tree for the combined TRI core gene cluster (TRI3, TRI4, TRI5, TRI7, TRI8, TRI11, and TRI13), including 22 isolates with F. sambucinum as the outgroup; (c) The most parsimonious tree for the combined TRI1 and TRI16 data set, including 22 isolates with F. sambucinum as the outgroup; (d) One of ten most-parsimonious trees for TRI101. Bootstrap intervals (10,000 replications) greater than 70% and Bayesian posterior probabilities greater than 0.90 are indicated as branches in bold in the phylogenetic trees. The type A trichothecene chemotypes (DAS and DAS-NEO-T2) are indicated by light grey (DAS lineage) and dark grey (DAS-NEO-T2 lineages).
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toxins-07-04577-f003: Maximum parsimony trees inferred in this study. (a) One of two most-parsimonious trees for the combined RPB1 and RPB2 data sets, including 22 isolates with F. sambucinum as the outgroup; (b) The most parsimonious tree for the combined TRI core gene cluster (TRI3, TRI4, TRI5, TRI7, TRI8, TRI11, and TRI13), including 22 isolates with F. sambucinum as the outgroup; (c) The most parsimonious tree for the combined TRI1 and TRI16 data set, including 22 isolates with F. sambucinum as the outgroup; (d) One of ten most-parsimonious trees for TRI101. Bootstrap intervals (10,000 replications) greater than 70% and Bayesian posterior probabilities greater than 0.90 are indicated as branches in bold in the phylogenetic trees. The type A trichothecene chemotypes (DAS and DAS-NEO-T2) are indicated by light grey (DAS lineage) and dark grey (DAS-NEO-T2 lineages).

Mentions: We used sequences of the RNA polymerase genes RPB1 and RPB2 to infer a species phylogeny of Type A trichothecene-producing fusaria. The RPB1 and RPB2 data set consisted of 22 taxa and 3260 nucleotides with 243 parsimony informative characters (PICs). The analysis resulted in two most parsimonious trees (CI = 0.90, RI = 0.94) (Figure 3a). No major topological variations were detected between trees derived from Neighbour-Joining, Parsimony and Bayesian phylogenetic inference. The species phylogeny was composed of four main lineages: (i) F. armeniacum, (ii) F. goolgardi, (iii) F. langsethiae-F. sibiricum-F. sporotrichioides and (iv) F. palustre. The closest relative of F. goolgardi was the F. langsethiae-F. sibiricum-F. sporotrichioides lineage. Within the F. goolgardi clade, a lineage was resolved that consisted of the four isolates with the DAS chemotype and a single isolate with a DAS-NEO-T2 chemotype (Figure 3a). The monophyly of this lineage was not rejected by the SH test (p > 0.05) and each lineage was supported by both BPP and MPBS.


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)

Maximum parsimony trees inferred in this study. (a) One of two most-parsimonious trees for the combined RPB1 and RPB2 data sets, including 22 isolates with F. sambucinum as the outgroup; (b) The most parsimonious tree for the combined TRI core gene cluster (TRI3, TRI4, TRI5, TRI7, TRI8, TRI11, and TRI13), including 22 isolates with F. sambucinum as the outgroup; (c) The most parsimonious tree for the combined TRI1 and TRI16 data set, including 22 isolates with F. sambucinum as the outgroup; (d) One of ten most-parsimonious trees for TRI101. Bootstrap intervals (10,000 replications) greater than 70% and Bayesian posterior probabilities greater than 0.90 are indicated as branches in bold in the phylogenetic trees. The type A trichothecene chemotypes (DAS and DAS-NEO-T2) are indicated by light grey (DAS lineage) and dark grey (DAS-NEO-T2 lineages).
© Copyright Policy
Related In: Results  -  Collection

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

toxins-07-04577-f003: Maximum parsimony trees inferred in this study. (a) One of two most-parsimonious trees for the combined RPB1 and RPB2 data sets, including 22 isolates with F. sambucinum as the outgroup; (b) The most parsimonious tree for the combined TRI core gene cluster (TRI3, TRI4, TRI5, TRI7, TRI8, TRI11, and TRI13), including 22 isolates with F. sambucinum as the outgroup; (c) The most parsimonious tree for the combined TRI1 and TRI16 data set, including 22 isolates with F. sambucinum as the outgroup; (d) One of ten most-parsimonious trees for TRI101. Bootstrap intervals (10,000 replications) greater than 70% and Bayesian posterior probabilities greater than 0.90 are indicated as branches in bold in the phylogenetic trees. The type A trichothecene chemotypes (DAS and DAS-NEO-T2) are indicated by light grey (DAS lineage) and dark grey (DAS-NEO-T2 lineages).
Mentions: We used sequences of the RNA polymerase genes RPB1 and RPB2 to infer a species phylogeny of Type A trichothecene-producing fusaria. The RPB1 and RPB2 data set consisted of 22 taxa and 3260 nucleotides with 243 parsimony informative characters (PICs). The analysis resulted in two most parsimonious trees (CI = 0.90, RI = 0.94) (Figure 3a). No major topological variations were detected between trees derived from Neighbour-Joining, Parsimony and Bayesian phylogenetic inference. The species phylogeny was composed of four main lineages: (i) F. armeniacum, (ii) F. goolgardi, (iii) F. langsethiae-F. sibiricum-F. sporotrichioides and (iv) F. palustre. The closest relative of F. goolgardi was the F. langsethiae-F. sibiricum-F. sporotrichioides lineage. Within the F. goolgardi clade, a lineage was resolved that consisted of the four isolates with the DAS chemotype and a single isolate with a DAS-NEO-T2 chemotype (Figure 3a). The monophyly of this lineage was not rejected by the SH test (p > 0.05) and each lineage was supported by both BPP and MPBS.

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.

Show MeSH
Related in: MedlinePlus