Biomass-degrading genes in button mushroom critical to managing planet's carbon stores

The button mushroom occupies a prominent place in our diet and in the grocery store where it boasts a tasty multibillion-dollar niche, while in nature, Agaricus bisporus is known to decay leaf matter on the forest floor.

Now, owing to an international collaboration of two-dozen institutions led by the French National Institute for Agricultural Research (INRA) and the US Department of Energy Joint Genome Institute (DOE JGI), the full repertoire of A. bisporus genes has been determined. In particular, new work shows how its genes are actually deployed not only in leaf decay but also wood decay and in the development of fruiting bodies (the above ground part of the mushroom harvested for food).

The work also suggests how such processes have major implications for forest carbon management.

The analysis of the inner workings of the world's most cultivated mushroom was published online the week of October 8 in the journal, the Proceedings of the National Academy of Sciences (PNAS).

''Our hypothesis was that metabolic strategies and niche adaptations of Agaricus might not be present in the white-rot and brown-rot wood-decomposing fungi,'' said senior author Francis Martin, Head of the 'ARBRE' Lab of Excellence at INRA, Nancy, France.

''Compared to genomes of these fungi, that we previously characterized, the Agaricus genome surprisingly has shown many similarities in gene composition,'' added Igor Grigoriev, the study's senior co-author and leader of the DOE JGI Fungal Program, ''At the same time, our data also supported the view that Agaricus fits neither brown-rot nor white-rot classifications and that its adaptation to growing in a leaf-litter humic-rich environment is not typical of classic wood degrading fungi.''