Mating-type locus structure affects gene expression in unidirectional mating-type switching fungi

To test how MAT1 structural variations affects gene expression, we studied Ceratocystis albifundus, a species that switches mating type. To minimise variability caused by intraspecific genetic differences, two self-sterile isolates (MAT-1 and MAT-2 self-steriles) were derived from the same MAT-2 self-fertile parent, making all three isolates genetically identical, except at the MAT1 locus. Comparative transcriptomic analyses revealed that the MAT-2 self-fertile, MAT-1 self-sterile and MAT-2 self-sterile isolates all exhibited distinct expression patterns, including differences in MAT genes, the pheromone–receptor pathway, and other genes not directly linked to mating.

The results show that MAT1 locus structure influences gene expression more broadly than those only related to the sexual cycle.