Abstract:
Genome sequencing of basidiomycetes, a group of fungi capable of degrading/mineralizing plant material, revealed the
presence of numerous cytochrome P450 monooxygenases (P450s) in their genomes, with some exceptions. Considering the
large repertoire of P450s found in fungi, it is difficult to identify P450s that play an important role in fungal metabolism and
the adaptation of fungi to diverse ecological niches. In this study, we followed Sir Charles Darwin’s theory of natural
selection to identify such P450s in model basidiomycete fungi showing a preference for different types of plant components
degradation. Any P450 family comprising a large number of member P450s compared to other P450 families indicates its
natural selection over other P450 families by its important role in fungal physiology. Genome-wide comparative P450
analysis in the basidiomycete species, Phanerochaete chrysosporium, Phanerochaete carnosa, Agaricus bisporus, Postia
placenta, Ganoderma sp. and Serpula lacrymans, revealed enrichment of 11 P450 families (out of 68 P450 families), CYP63,
CYP512, CYP5035, CYP5037, CYP5136, CYP5141, CYP5144, CYP5146, CYP5150, CYP5348 and CYP5359. Phylogenetic analysis
of the P450 family showed species-specific alignment of P450s across the P450 families with the exception of P450s of
Phanerochaete chrysosporium and Phanerochaete carnosa, suggesting paralogous evolution of P450s in model
basidiomycetes. P450 gene-structure analysis revealed high conservation in the size of exons and the location of introns.
P450s with the same gene structure were found tandemly arranged in the genomes of selected fungi. This clearly suggests
that extensive gene duplications, particularly tandem gene duplications, led to the enrichment of selective P450 families in
basidiomycetes. Functional analysis and gene expression profiling data suggest that members of the P450 families are
catalytically versatile and possibly involved in fungal colonization of plant material. To our knowledge, this is the first report
on the identification and comparative-evolutionary analysis of P450 families enriched in model basidiomycetes.
