Fungal Cytochrome P450s and the P450 Complement (CYPome) of Fusarium graminearum

Abstract

Cytochrome P450s (CYPs), heme-containing monooxygenases, play important roles in a wide variety of metabolic processes important for development as well as biotic/trophic interactions in most living organisms. Functions of some CYP enzymes are similar across organisms, but some are organism-specific; they are involved in the biosynthesis of structural components, signaling networks, secondary metabolisms, and xenobiotic/drug detoxification. Fungi possess more diverse CYP families than plants, animals, or bacteria. Various fungal CYPs are involved in not only ergosterol synthesis and virulence but also in the production of a wide array of secondary metabolites, which exert toxic effects on humans and other animals. Although few studies have investigated the functions of fungal CYPs, a recent systematic functional analysis of CYP genes in the plant pathogen Fusarium graminearum identified several novel CYPs specifically involved in virulence, asexual and sexual development, and degradation of xenobiotics. This review provides fundamental information on fungal CYPs and a new platform for further metabolomic and biochemical studies of CYPs in toxigenic fungi.

Keywords: Fusarium graminearum; cytochrome P450; secondary metabolism; xenobiotics.

Figure 1

Chemical structures of mycotoxins. Chemical structures were obtained from PubChem (https://pubchem.ncbi.clm.cih.gov) [117].

Figure 2

Classification of putative CYPs in F. graminearum. Total CYPs were categorized into six classes based on InterPro terms. These data were reproduced from [20]. Copyright 2017, John Wiley & Sons.

Figure 3

Phenotypic analyses of CYP deletion mutants of F. graminearum. (a) Altered xenobiotic stress response of wild type (Z-3639) and one CYP deletion mutant. DD, 1-dodecanol; (b) Development of perithecia (upper panel) and formation of asci rosettes (lower panel); A CYP gene deletion strain (right panel) showed defects in perithecia and ascospore formation whereas the parent strain (left panel) displayed normal perithecia and ascospores. Scale bar = 500 μm (upper), 20 μm (lower left), and 200 μm (lower right); (c) Altered ultra-violet (UV) stress response of wild type and CYP mutant strain; (d) Virulence of wild-type and CYP deletion strains on wheat heads. Five mutants showed reduced virulence compared to the wild-type strain (Z-3639). These data have been reproduced from [21] with slight modifications, Copyright 2013, John Wiley & Sons.

Figure 4

Fusarium trichothecene biosynthetic pathway. CYP enzymes, Tri1, Tri4, Tri11, Tri13, are involved in trichothecene biosynthesis. This scheme has been derived from [71] with slight modifications, Copyright 2007, Japan Society for Bioscience, Biotechnology, and Agrochemistry.