Arend van Peer, Han Wösten
The ascomycetes and basidiomycetes comprise most of the species of filamentous fungi. The hyphae of these fungi are capable of forming complex, well-organised structures such as mycelia and mushrooms. Fungal hyphae are made up of cytoplasmic compartments that are separated by perforated septa. Thus, the cytoplasm within a mycelium seems to be a continuous system. Septa are crucial for important processes such as differentiation (e.g. sporulation) and damage control. A wide variation exists in septal morphology. Ascomycetes are characterized by relatively simple structured septa, while those of basidiomycetes can be very complex.
Basidiomycete septa contain a characteristic rim around their central pore, the dolipore, which in higher basidiomycetes is often covered by a septal pore cap (SPC). The existence of the SPC was already reported in 1958 (Girbardt 1958) . However, its function is still unknown. We hypothesize that this structure is of importance for long distance growth of hyphae over non-nutritive substrates. At the moment we purify the SPCs of the basidiomycetes Schizophyllum commune (UU) and Rhizoctonia solani (CBS) by gradient centrifugation. Fractions are analysed by electron microscopy. The composition of the SPC will be analysed and the genes involved identified. We will establish the function of the SPC by gene deletions.