Mushroom Formation in Schizophyllum commune: The Central Role of cAMP in CO2 Sensing

Abstract

Environmental CO2 is recognized to be one of the main factors involved in mushroom formation in many fungi, including the model fungus Schizophyllum commune. It has been established that cyclic AMP (cAMP) plays a central role in regulation of fructification, however, it remains unclear how the intracellular cAMP concentration is regulated and how this affects fructification throughout the process. cAMP is produced by adenylyl cyclase, whereas breakdown is achieved by phosphodiesterases (PDEs). An attempt has been made at the deletion of the high-affinity PDE (Pde2) of S. commune, though no transformants were obtained. Moreover, efforts were made towards a titratable conditional gene expression in S. commune, by developing the required constructs for the Tet-on system. In this initial setup, the reporter gene dTomato is used to show the viability of the system in S. commune. The Tet-on system may prove useful as a novel strategy in interference with genes, Pde2 being a prime candidate. Additionally, the use ring plates has been introduced for phenotyping of colonies. Altogether, valuable tools have been prepared which will improve future research methods. Finally, some colonies were mutated into the streak morphology during transformation by accident. Evidently, streak colonies show red autofluorescence, whereas WT colonies do not.