Genomics, transcriptomics and proteomics analyses reveal a high lignocellulose degradation capacity of the basidiomycete fungus Macrolepiota fuliginosa

Macrolepiota fuliginosa (Barla) Bon, is a litter-decomposing basidiomycete belonging to the order Agaricales. Due to their morphological similarities it was originally classified as a variety of Macrolepiota procera (Macrolepiota procera var. fuliginosa (Barla) Bellù & Lanzonidue). Macrolepiota species are very popular edible fungi (many local names are used to identify this fungus) because of his organoleptic properties and large size. They grow preferentially in Fagus, Quercus or conifer forests glades of temperate regions, playing an important role in the breakdown and chemical conversion of lignocellulose components to simpler compounds.

Genomic analyses confirm a close phylogenetic relationship with Agaricus bisporus, and show a broad portfolio of lignocellulose degrading enzymes. As a white rot fungus, M. fuliginosa shows cellulose degrading enzymes GH6, GH7 and AA1, and also possesses and impressive number of lignin degrading enzymes, especially laccases(AA1_1) and GMC oxidoreductases(AA3_2). Furthermore, it shows a surprisingly high number of genes classified as cytochrome P450(CYP), a family of proteins involved in many processes including the degradation of lignocellulosic compounds and present in a much smaller number in phylogenetically close fungi.

Comparative transcriptomic and proteomic analyses of M. fuliginosa growing on lignocellulose substrate versus glucose rich media demonstrate a high capacity of degrading enzymes secretion and a clear overexpression of these enzymes, highlighting M. fuliginosa ability to degrade lignocellulosic substrates.