Homeodomain 1 Genes of the Different HD Subloci of Flammulina velutipes Can Activate the HD Pathway and Are Involved in Mating, Clamp Cell Formation, and Upregulation of FvClp1

has two independent and functional mating type factors, HD and PR. The HD locus contains two separate subloci: HD-a and HD-b. In this study, we investigated the roles of