Cytological studies on sporeless mutant in the basidiomyceteCoprinus macrorhizus

Abstract

Meiotic events in the sporeless mutant, NG107, and in the wild-type dikaryon of the basidiomyceteCoprinus macrorhizus were studied comparatively with light and electron microscopes in order to determine precisely which meiotic process was blocked in the mutant. In most basidia of the mutant, when incubated at 28 C, meiosis stopped at meta-anaphase I although the kinetic apparatus was formed. Then, the basidia became mononucleate, electron dense, and finally disintegrated. This mutant, when incubated at 20 C, produced basidiospores approximately one third of the wild-type. Basidia with irregular number of spores were observed in higher frequency than in the wild-type. Experimental results of temperature shifts from 28 C to 20 C and the reciprocal shift suggest that meta-anaphase I might be thermosensitive in the mutant.