Identification mating-type locus structure and distribution of Cochliobolus lunatus in China

Cochliobolus lunatus (teleomorph: Curvularia lunata) is an important plant pathogenic fungus that causes the maize foliar spot, resulting in serious yield losses. In ascomycetes, a single mating-type (MAT) locus with two idiomorphs controls sexual development. The structure and arrangement of the MAT genes were examined to understand the MAT locus of C. lunatus. MAT loci were MAT1–1-1 or MAT1–2-1, flanked upstream and downstream by regions encoding GTPase activating protein, pyridoxamine phosphate oxidase domain, and β-glucosidase. A MAT1–1 or MAT1–2 idiomorph was identified in single isolate, and sexual reproduction in vitro indicated that the species was heterothallic. In vitro crossing between isolates with opposite MATs produced perithecia, asci, and ascospores. A multiplex MAT-specific PCR method was developed and used to test mating-type genes in 177 C.lunatus isolates collected from China. The ratio of isolates of each mating-type in China was consistent with a 1:1 ratio.