GLUCOAMYLASE ACTIVITY AND WATER-SOLUBLE POLYSACCHARIDES DURING MONOKARYOTIC AND DIKARYOTIC FRUITING IN SCHIZOPHYLLUM-COMMUNE

In monokaryons and dikaryons of Schizophyllum commune, light may either increase or decrease glycogen-degrading activity, most of which is due to glucoamylase activity. In haploid strains producing monokaryotic fruit bodies, glucoamylase activity increased in light and was associated with breakdown of glycogen. No such changes took place in monokaryotic strains unable to form fruit bodies. These observations suggest that the increase in glucoamylase activity in light could contribute some endogenous glucose originating from glycogen for fruit body differentiation. However, in dikaryons formed by mating monokaryotic fruiters with high glucoamylase activity in light, no increase in glucoamylase activity was observed in light and the glycogen content of the mycelia was low. The failure of light to induce glucoamylase activity could be associated with regulation of dikaryotic fruiting by incompatibility genes. These might control the synthesis of water-soluble polysaccharides other than glycogen in the dark and mediate light induction of other enzyme(s) than glucoamylase during dikaryotic fruit body differentiation in light.