Three copies of the mating-type genes, which determine cell type, are found in the budding yeast Saccharomyces cerevisiae. The copy at the MAT locus is transcriptionally active, whereas identical copies of the mating-type genes at the HML and HMR loci are transcriptionally silent. Hence, HML and HMR, also known as the silent mating-type loci, are subject to a position effect. Regulatory sequenc...

Hybridization with polyploidization is a significant biological force driving evolution. The effect of combining two distinct genomes in one organism on the virulence potential of pathogenic fungi is not clear. Cryptococcus neoformans, the most common cause of fungal infection of the central nervous system, has a bipolar mating system with a and alpha mating types and occurs as A (haploid), D (...

The HO gene promotes interconversion between a and a mating types. As a consequence, homothallic diploid cells are formed by mating between siblings descended from a single crH0 or a HO spore. In order to determine the frequency and pattern of the mating-type switch, we have used a simple technique by which the mating phenotype can be assayed without losing the cell to the mating process itself...

Regions of the chromosomes determining mating compatibility in some fungi, including Microbotryum lychnidis-dioicae and Neurospora tetrasperma, exhibit suppressed recombination similar to sex chromosomes in plants and animals, and recent studies have sought to apply basic theories of sex chromosome evolution to fungi. A phylogeny of the MTL1 locus in Microbotryum indicates that it has become pa...

Eyespot, caused by the related fungal pathogens Oculimacula acuformis and O. yallundae, is an important cereal stem-base disease in temperate parts of world. Both species are dispersed mainly splash-dispersed conidia but also known to undergo sexual reproduction, yielding apothecia containing ascospores. Field diagnosis eyespot can be challenging, with other causing similar symptoms, which comp...

The significance of sexual selection, the component of natural selection associated with variation in mating success, is well established for the evolution of animals and plants, but not for the evolution of fungi. Even though fungi do not have separate sexes, most filamentous fungi mate in a hermaphroditic fashion, with distinct sex roles, that is, investment in large gametes (female role) and...

The pennate diatom Seminavis robusta, characterized by an archetypical diatom life cycle including a heterothallic mating system, is emerging as a model system for studying the molecular regulation of the diatom cell and life cycle. One of its main advantages compared with other diatom model systems is that sexual crosses can be made routinely, offering unprecedented possibilities for forward g...

To reevaluate two dictyostelid species, namely, Polysphondylium pallidum and P. album, 92 isolates of the P. pallidum complex from their type localities were examined based on mating relationships and morphological characteristics. In the mating tests three heterothallic mating groups were found among the isolates. They also were different morphologically from each other. These results suggeste...