The Maize Pathogen Ustilago maydis Secretes Glycoside Hydrolases and Carbohydrate Oxidases Directed toward Components of the Fungal Cell Wall
Jean‐Lou Reyre, Sacha Grisel, Mireille Haon, David Navarro, David Ropartz, Sophie Le Gall, Éric Record, Giuliano Sciara, Olivier Tranquet, Jean‐Guy Berrin, Bastien Bissaro
Abstract
Filamentous fungi play a central regulatory role on Earth, notably in the global carbon cycle. Regardless of their lifestyle, filamentous fungi need to remodel their own cell wall (mostly composed of polysaccharides) to grow and proliferate. To do so, they must secrete a large arsenal of enzymes, most notably carbohydrate-active enzymes (CAZymes). However, research on fungal CAZymes over past decades has mainly focused on finding efficient plant biomass conversion processes while CAZymes directed at the fungus itself have remained little explored. In the present study, using the maize pathogen Ustilago maydis as model, we set off to evaluate the prevalence of CAZymes directed toward the fungal cell wall during growth of the fungus on plant biomass and characterized two new CAZymes active on fungal cell wall components. Our results suggest the existence of a biocatalytic cascade that remains to be fully understood.