The mating-type and pathogenicity locus of the fungus Ustilago hordei spans a 500-kb region
Year: 1999
Type: article
Abstract: The fungal pathogen Ustilago hordei causes the covered smut disease of barley and oats. Mating and pathogenicity in this fungus are controlled by the MAT locus, which contains two distinct gene complexes, a and b. In this study, we tagged the a and b regions with the recognition sequence for the restriction enzyme I-SceI and determined that the distance between the complexes is 500 kb in a MAT-1 strain and 430 kb in a MAT-2 strain. Characterization of the organization of the known genes within the a and b gene complexes provided evidence for nonhomology and sequence inversion between MAT-1 and MAT-2. Antibiotic-resistance markers also were used to tag the a gene complex in MAT-1 strains (phleomycin) and the b gene complex in MAT-2 strains (hygromycin). Crosses were performed with these strains and progeny resistant to both antibiotics were recovered at a very low frequency, suggesting that recombination is suppressed within the MAT region. Overall, the chromosome homologues carrying the MAT locus of U. hordei share features with primitive sex chromosomes, with the added twist that the MAT locus also controls pathogenicity.
Authors: Nancy Lee, Guus Bakkeren, Katherine Wong, John E. Sherwood, James W. Kronstad
Institutions: University of British Columbia, Montana State University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W2018560042