Fungal growth and development visualization in Schizophyllum commune

The basidiomycete Schizophyllum commune belongs to the white rot fungi and is relevant for wood degradation worldwide. As early colonizer of tree wounds and after forest fire, the fungus has also phytopathogenic importance. Its high competitive ability is based on the recognition of other fungi and bacteria, the production of specific extracellular metabolites and a strategy of fast growth. The fungal cytoskeleton, composed of a complex network of microtubules and actin structures, has a major impact on transport of vesicles as well as endo- and exocytosis processes. Visualization of the actin cytoskeleton in actively growing hyphae was performed with Lifeact-GFP. Thereby cortical actin patches were visualized at cell tips and clamps and as well as in subapical cells, preceded septation. The actin cytoskeleton in living hyphae during septum development shows close association with nuclear division. Clamp cell formation, typical of many model basidiomycetes including S. commune, indicated an aggregation of actin filaments to ring structures at the future site of nuclear division. Additionally, GFP-labeling of histone H2B enables visualization of nuclear movement and mitosis events in monokaryotic and dikaryotic cells. Further fast nuclear exchange in anastomoses after mating could be shown.