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. 1994 Jul 19;91(15):7085–7089. doi: 10.1073/pnas.91.15.7085

Linkage of mating-type loci distinguishes bipolar from tetrapolar mating in basidiomycetous smut fungi.

G Bakkeren 1, J W Kronstad 1
PMCID: PMC44343  PMID: 7913746

Abstract

Sexual compatibility requires self vs. non-self recognition. Genetically, two compatibility or mating-type systems govern recognition in heterothallic basidiomycete fungi such as the edible and woodrotting mushrooms and the economically important rust and smut phytopathogens. A bipolar system is defined by a single genetic locus (MAT) that can have two or multiple alleles. A tetrapolar system has two loci, each with two or more specificities. We have employed two species from the genus Ustilago (smut fungi) to discover a molecular explanation for the genetic difference in mating systems. Ustilago maydis, a tetrapolar species, has two genetically unlinked loci that encode the distinct mating functions of cell fusion (a locus) and subsequent sexual development and pathogenicity (b locus). We have recently described a b locus in a bipolar species, Ustilago hordei, wherein the existence of an a locus has been suspected, but not demonstrated. We report here the cloning of an allele of the a locus (a1) from U. hordei and the discovery that physical linkage of the a and b loci in this bipolar fungus accounts for the distinct mating system. Linkage establishes a large complex MAT locus in U. hordei; this locus appears to be in a region suppressed for recombination.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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