Introduction While most studies focus on the effectors involved in plant infection, another important aspect is the degradation of the plant cell wall, as this is the main physical barrier protecting the plant from pathogens. The plant cell wall mainly consists of polysaccharides, proteins and the aromatic polymer lignin, but the type of polysaccharide differs significantly between plant types, species and tissues. It can therefore be expected that pathogens of specific plants have evolved to produce those plant polysaccharide degrading enzymes that match the polysaccharides in the cell wall of their host plant. Methods In this study, we compared the plant polysaccharide degradation potential of 56 Dothideomycetes and 42 Sordariomycetes species to identify evolutionary patterns related to either host plant or phylogenomic classification of the fungal species. Results and discussion Our results show that the CAZy content of these fungi does not correlate with their genome-based phylogeny, indicating that the CAZome has evolved separately from the overall genome, possibly under different selection pressures. In some cases, clear adaptation of the fungal genome to the host plant of the fungus can be observed, including an indication of parallel evolution among Sordariomycetes and Dothidiomycetes species. We mainly detected intergeneric variation in CAZome, while intrageneric diversity was low. This may indicate that initial adaptation is predominantly at the level of gene expression variation of specific CAZy genes, while over longer taxonomic timeframes, evolution of genome content becomes apparent.
Kandemir et al. (Tue,) studied this question.