Kinetics of asymmetric mycelial growth and control by dikaryosis and light in Schizophyllum commune

Abstract

An asymmetric form of mycelial growth is described for isolates of Schizophyllum commune. This growth form is limited to dikaryons and is characterized by a decreasing rate of hyphal extension followed by the development of a chaotic mycelial form when grown on semisolid media. The component homokaryons of these dikaryons do not display this growth form but grow in a circularly symmetrical pattern. The chaotic growth of these dikaryons is induced by light. Dikaryons grown in total darkness had rates of growth and mycelial pattern similar to that of homokaryons. Chaotic growth is also associated with an inability of dikaryotic mycelia to fuse. Mycelia with a uniform growth habit will always fuse, while chaotic mycelia fuse only with difficulty on fresh medium when inoculated less than 10 mm apart. The kinetics of dikaryotic growth and the results of the fusion tests suggest the presence of an auto-inhibitor of growth regulated by light and dikaryosis.

Key Words:

• auto-inhibitor
• development
• pattern formation