Control of unusual hyphal morphology in a mutant of coprinus macrorhizus

Characteristics of a mutant of Coprinus macrorhizus which forms white callus-like masses of densely packed hyphae designated as “rockery” have been described. Formation of both rockeries and monokaryotic fruiting bodies required light, but rockeries once formed inhibited the formation of monokaryotic fruiting bodies. Genetic analyses revealed that this mutant carried the genes for rockery formation (roc) and monokaryotic fruiting (fis^C5), but the expression of roc and fis^C5 was suppressed in dikaryons. The expression of rockery character resulted in suppression of production of tyrosinase and melanin in mycelia of roc fis^C5 strain.