The a locus governs cytoduction in Ustilago maydis.
We have developed a cytoduction assay to measure cell fusion quantitatively in the basidiomycete corn smut fungus Ustilago maydis. This assay employs a mutation conferring resistance to oligomycin that exhibits non-Mendelian inheritance and presumably affects the mitochondrial genome. After auxotrophic olir cells are mixed with prototrophic olis cells, prototrophic olir cells can be detected at a significant frequency after several hours of incubation, reaching a maximum of 10% of the total prototrophs in the mixture after 18 h. We demonstrate that this cell fusion event occurs only if the mating partners have different alleles of the a mating-type locus and is not influenced by the b locus. These studies support the view that the a locus but not the b locus controls establishment of the filamentous, pathogenic state.
Trueheart
J
J
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Herskowitz
I
I
D002459:Cell Fusion / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D005111:Extrachromosomal Inheritance; D005800:Genes, Fungal / Q000235:genetics*; D049770:Genes, Mating Type, Fungal; D008928:Mitochondria / Q000502:physiology; D009840:Oligomycins / Q000494:pharmacology; D014588:Ustilago / Q000187:drug effects / Q000502:physiology*
D009840:Oligomycins