Generic model of morphological changes in growing colonies of fungi

Fungal colonies are able to exhibit different morphologies depending on the enviromental conditions. This allows them to cope with and adapt to external changes. When grown in solid or semi-solid media the bulk of the colony is compact and several morphological transitions have been reported to occur as the external conditions are varied. Here we show how a unified simple mathematical model, which includes the effect of the accumulation of toxic metabolites, can account for the morphological changes observed. Our numerical results are in excellent agreement with experiments carried out with the fungus Aspergillus oryzae on solid agar.