Mating-type loci of Ustilago esculenta are essential for mating and development.

•Three a alleles and three b alleles in U. esculenta were cloned so far.•The a locus encodes 2 pheromones and a receptor, with a structural variant a3 allele.•The a locus is responsible for the conjugation formation and cells fusion.•The b locus is essential for hyphal growth and pathogenicity.•A solopathogenic strain UeTSP could trigger hyphal growth and infection.