Functional Analysis of the Polyketide Synthase Genes in the Filamentous FungusGibberella zeae(AnamorphFusarium graminearum)

Abstract

Polyketides are a class of secondary metabolites that exhibit a vast diversity of form and function. In fungi, these compounds are produced by large, multidomain enzymes classified as type I polyketide synthases (PKSs). In this study we identified and functionally disrupted 15 PKS genes from the genome of the filamentous fungus Gibberella zeae. Five of these genes are responsible for producing the mycotoxins zearalenone, aurofusarin, and fusarin C and the black perithecial pigment. A comprehensive expression analysis of the 15 genes revealed diverse expression patterns during grain colonization, plant colonization, sexual development, and mycelial growth. Expression of one of the PKS genes was not detected under any of 18 conditions tested. This is the first study to genetically characterize a complete set of PKS genes from a single organism.

Dothideomycete–Plant Interactions Illuminated by Genome Sequencing and EST Analysis of the Wheat Pathogen Stagonospora nodorum

“…This may be due to their large size or to a generally low level of expression. Polyketide synthases (PKSs) are a second modular gene family strongly associated with pathogenicity (Kroken et al, 2003;Gaffoor et al, 2005), being responsible for the production of T-toxin from C. heterostrophus and PM-toxin from Mycosphaerella zeae-maydis (Yun et al, 1998;Baker et al, 2006). S. nodorum is predicted to contain 19 PKS genes compared with the 24, 14, and 24 in the pathogens M. grisea, Fusarium graminearum, and C. heterostrophus, respectively, and 28 in the saprobe A. nidulans but significantly more than the seven in N. crassa (Table 5).…”

Phylogenomic analysis of polyketide synthase-encoding genes in Trichoderma

“…Non-ribosomal peptides and polyketides comprise a major portion of these products, which are synthesized by large proteins composed of various domains for the individual enzymic steps (Cox, 2007). Both broad and genus-specific phylogenomic and functional analysis of polyketide synthase (PKS)-and non-ribosomal peptide synthetase (NRPS)-encoding genes have been performed, which has accelerated the pace at which genes and pathways are being linked to specific secondary metabolites (Bushley & Turgeon, 2010;Bushley et al, 2008;Chiang et al, 2010;Cramer et al, 2006;Gaffoor et al, 2005;Kroken et al, 2003;Kubicek et al, 2011;Lee et al, 2005).Trichoderma spp. are probably best known for their production of peptaibols, which are non-ribosomal peptides with antimicrobial and plant defence-stimulating activity (Viterbo et al, 2007).…”

Rational reprogramming of fungal polyketide first-ring cyclization

“…Although the biosynthesis of most fungal polyketides requires a single iPKS enzyme, the assembly of the resorcylic acid lactones (RALs) involves a pair of collaborating hrPKSs and nrPKSs acting in sequence (12)(13)(14)(15)(16)(17). Fungal RALs are rich pharmacophores with estrogen agonist (zearalenone), mitogen-activated protein kinase inhibitory (hypothemycin), and heat shock response modulatory activities [radicicol and monocillin II (1)] ( Fig.…”