Sexual Differentiation Is Coordinately Regulated by and .

The heterothallic basidiomycetous fungus has two mating types, and α. Morphological progression of bisexual reproduction in is as follows: yeast to hyphal transition, filament extension, basidium formation, meiosis, and sporulation. Cdk-related kinase 1 () is a negative regulator of bisexual mating. In this study, we characterized the morphological features of mating structures in the mutant and determined the genetic interaction of in the regulatory networks of sexual differentiation. In the bilateral mutant cross, despite shorter length of filaments than in the wild-type cross, dikaryotic filaments and other structures still remained intact during bisexual mating, but the timing of basidium formation was approximately 18 h earlier than in the cross between wild type strains. Furthermore, gene expression analyses revealed that modulated the expression of genes involved in the progression of hyphal elongation, basidium formation, karyogamy and meiosis. Phenotypic results showed that, although deletion of gene increased the efficiency of bisexual mating, filamentation in the mutant was blocked by or mutation. A bioinformatics survey predicted the GATA transcriptional factor Gat1 as a potential substrate of Crk1 kinase. Our genetic and phenotypic findings revealed that and formed a regulatory circuit to negatively regulate to control filamentation progression and transition during bisexual mating.