Phylogenomic analysis of type I polyketide synthase genes in pathogenic and saprobic ascomycetes

Abstract

Fungal type I polyketides (PKs) are synthesized by PK synthases (PKSs) and include well known secondary metabolites such as the anticholesterol drug lovastatin and the potent natural carcinogen aflatoxin. Other type I PKs are known to be virulence factors for some plant pathogens and pigments such as melanin. In this study, a phylogenomic approach was used to investigate the origin and diversity of fungal genes encoding putative PKSs that are predicted to synthesize type I PKs. The resulting genealogy, constructed by using the highly conserved PKS ketosynthase (

Functional characterization of Fusarium verticillioides CPP1, a gene encoding a putative protein phosphatase 2A catalytic subunit

“…As there are over 15 PKS genes in F. verticillioides (Kroken et al, 2003), we next investigated the specificity of CPP1 to regulation of FUM1. Kroken et al (2003) classified 15 type-I PKS genes present in F. verticillioides into major clades or subclades.…”

“…Kroken et al (2003) classified 15 type-I PKS genes present in F. verticillioides into major clades or subclades. To test the impact of CPP1 deletion on the expression of PKS genes, we selected four PKS genes from different subclades: PKS1 (reducing PKS clade II), PKS2 (reducing PKS clade I), PKS4 (non-reducing PKS clade I) and PKS11 (FUM1, reducing PKS clade III).…”

“…4b). PKS1 and PKS2 were classified, along with FUM1, as reducing PKSs, whereas PKS4 resided in a separate group of non-reducing PKSs (Kroken et al, 2003). Interestingly, deletion of CPP1 did not have a drastic effect on the expression of other PKS genes, suggesting that the regulatory role of CPP1 is specific to FUM genes and FB 1 biosynthesis (Fig.…”

“…FB 1 , the major fumonisin produced by F. verticillioides, was extracted and analysed by HPLC, following the method described by Shim & Woloshuk (1999). In addition to FB 1 HPLC analysis, qRT-PCR was used to investigate the relative expression of FUM1 and other selected PKS genes (Kroken et al, 2003) in the WT and mutant strains. Total RNA samples were prepared from the WT, PP87, PP179 and PPC4 grown on cracked-corn medium for 10 days, and qRT-PCR analysis was performed with SYBR-Green as the fluorescent reporter, using gene-specific primers (FUM1-F and FUM1-R2) for the FUM1 gene.…”

Identification of a cis-acting factor modulating the transcription of FUM1, a key fumonisin-biosynthetic gene in the fungal maize pathogen Fusarium verticillioides

“…Indeed, the FUM cluster in A. niger probably originated by horizontal gene transfer from a common ancestor prior of the divergence between F. verticillioides and F.oxysporum ( Khaldi and Wolfe, 2011). Interestingly, a gene-by-gene phylogenetic analysis revealed a total of 13 putative orthologues of FUM genes (FUM1,, scattered in the genomes of five other Euascomycetes: Cochliobolus heterostrophus ( Kroken et al, 2003), Fusarium graminearum, Neurospora crassa, Magnaporthe grisea, and Aspergillus nidulans ( Khaldi and Wolfe, 2011). Physical clustering of genes may also influence the evolution of their regulatory sequences, likely due to the possibility of tight co-regulation of expression by localized events of chromatin remodelling, and to the activity of pathwayspecific regulators embedded in the cluster ( Bayram andBraus, 2012 andYu and.…”