Dataset Information

Characterization of two polyketide synthase genes involved in zearalenone biosynthesis in Gibberella zeae.

ABSTRACT: Zearalenone, a mycotoxin produced by several Fusarium spp., is most commonly found as a contaminant in stored grain and has chronic estrogenic effects on mammals. Zearalenone is a polyketide derived from the sequential condensation of multiple acetate units by a polyketide synthase (PKS), but the genetics of its biosynthesis are not understood. We cloned two genes, designated ZEA1 and ZEA2, which encode polyketide synthases that participate in the biosynthesis of zearalenone by Gibberella zeae (anamorph Fusarium graminearum). Disruption of either gene resulted in the loss of zearalenone production under inducing conditions. ZEA1 and ZEA2 are transcribed divergently from a common promoter region. Quantitative PCR analysis of both PKS genes and six flanking genes supports the view that the two polyketide synthases make up the core biosynthetic unit for zearalenone biosynthesis. An appreciation of the genetics of zearalenone biosynthesis is needed to understand how zearalenone is synthesized under field conditions that result in the contamination of grain.

SUBMITTER: Gaffoor I

PROVIDER: S-EPMC1393172 | biostudies-other | 2006 Mar

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Characterization of two polyketide synthase genes involved in zearalenone biosynthesis in Gibberella zeae.

Gaffoor Iffa I Trail Frances F

Applied and environmental microbiology 20060301 3

Zearalenone, a mycotoxin produced by several Fusarium spp., is most commonly found as a contaminant in stored grain and has chronic estrogenic effects on mammals. Zearalenone is a polyketide derived from the sequential condensation of multiple acetate units by a polyketide synthase (PKS), but the genetics of its biosynthesis are not understood. We cloned two genes, designated ZEA1 and ZEA2, which encode polyketide synthases that participate in the biosynthesis of zearalenone by Gibberella zeae ( ...[more]

PMID: 16517624

Similar Datasets

Project description:The fungus Trichoderma arundinaceum exhibits biological control activity against crop diseases caused by other fungi. Two mechanisms that likely contribute to this activity are upregulation of plant defenses and production of two types of antifungal secondary metabolites: the sesquiterpenoid harzianum A (HA) and the polyketide-derived aspinolides. The goal of the current study was to identify aspinolide biosynthetic genes as part of an effort to understand how these metabolites contribute to the biological control activity of T. arundinaceum. Comparative genomics identified two polyketide synthase genes (asp1 and asp2) that occur in T. arundinaceum and Aspergillus ochraceus, which also produces aspinolides. Gene deletion and biochemical analyses in T. arundinaceum indicated that both genes are required for aspinolide production: asp2 for formation of a 10-member lactone ring and asp1 for formation of a butenoyl subsituent at position 8 of the lactone ring. Gene expression and comparative genomics analyses indicated that asp1 and asp2 are located within a gene cluster that occurs in both T. arundinaceum and A. ochraceus. A survey of genome sequences representing 35 phylogenetically diverse Trichoderma species revealed that intact homologs of the cluster occurred in only two other species, which also produced aspinolides. An asp2 mutant inhibited fungal growth more than the wild type, but an asp1 mutant did not, and the greater inhibition by the asp2 mutant coincided with increased HA production. These findings indicate that asp1 and asp2 are aspinolide biosynthetic genes and that loss of either aspinolide or HA production in T. arundinaceum can be accompanied by increased production of the other metabolite(s). KEY POINTS: • Two polyketide synthase genes are required for aspinolide biosynthesis. • Blocking aspinolide production increases production of the terpenoid harzianum A. • Aspinolides and harzianum A act redundantly in antibiosis of T. arundinaceum.

Dataset Information

Characterization of two polyketide synthase genes involved in zearalenone biosynthesis in Gibberella zeae.

Publications

Characterization of two polyketide synthase genes involved in zearalenone biosynthesis in Gibberella zeae.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets