title: Mating type loci of Sporisorium reilianum: novel pattern with three a and multiple b specificities.
abstract: Sporisorium reilianum and Ustilago maydis are two closely related smut fungi, which both infect maize but differ fundamentally in their mode of plant invasion and site of symptom development. As a prelude to studying the molecular basis of these differences, we have characterized the mating type loci of S. reilianum. S. reilianum has two unlinked mating type loci, a and b. Genes in both loci and adjacent regions show a high degree of synteny to the corresponding genes of U. maydis. The b locus occurs in at least five alleles and encodes two subunits of a heterodimeric homeodomain transcription factor, while the a locus encodes a pheromone/receptor system. However, in contrast to that of U. maydis, the a locus of S. reilianum exists in three alleles containing two active pheromone genes each. The alleles of the a locus appear to have arisen through recent recombination events within the locus itself. This has created a situation where each pheromone is specific for recognition by only one mating partner.
authors.affiliation: Max-Planck-Institut für Terrestrische Mikrobiologie, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Schirawski
authors.forename: Bernadette
authors.initials: B
authors.lastname: Heinze
authors.forename: Martin
authors.initials: M
authors.lastname: Wagenknecht
authors.forename: Regine
authors.initials: R
authors.lastname: Kahmann
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry; D005800:Genes, Fungal / Q000235:genetics*; D014644:Genetic Variation; D025301:Hyphae / Q000235:genetics; D008969:Molecular Sequence Data; D010675:Pheromones / Q000235:genetics / Q000502:physiology; D010802:Phylogeny; D043563:Receptors, Pheromone / Q000235:genetics / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014588:Ustilago / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D010675:Pheromones; D043563:Receptors, Pheromone