Phenotypic plasticity in fungi: a review with observations on Aureobasidium pullulans.

Phenotypic plasticity in fungi is reviewed in the context of observations on phenotypic changes in the colony morphology of the fungus Aureobasidium pullulans. The variation in colony form is shown to depend on (i) the types of single carbon substrates (sugars and sugar alcohols) used in the growth medium, (ii) colony age, (iii) incubation temperature, (iv) light cycle and (v) substrate type. Expanding colonies grow in a developmental sequence that show synchronize growth phase shifts as well as unusual transitions from homogeneous to sectored, yeast to mycelial and giant to microcolonial growth forms. Epigenetic influences on phenotypic switches are suggested to be potential causes of form changes. The desirable properties of a model organism for studying phenotypic plasticity are discussed and past work on the yeast-mycelial transition of fungi is reviewed.