An agar medium-based method for screening somatic incompatibility in Agaricus bisporus.

To visualize the nonself recognition reaction in the cultivated mushroom Agaricus bisporus, we developed a method using the azo dye Evans blue. The use of Evans blue highlights dead mycelial sections, which are produced following nonself recognition in the interaction zone between two individuals. This method can differentiate between distinct heterokaryons, as well as between closely related heterokaryons constructed from siblings.

The Narrow Footprint of Ancient Balancing Selection Revealed by Heterokaryon Incompatibility Genes in Aspergillus fumigatus.

In fungi, fusion between individuals leads to localized cell death, a phenomenon termed heterokaryon incompatibility. Generally, the genes responsible for this incompatibility are observed to be under balancing selection resulting from negative frequency-dependent selection. Here, we assess this phenomenon in Aspergillus fumigatus, a human pathogenic fungus with a very low level of linkage disequilibrium as well as an extremely high crossover rate.

The human fungal pathogen Aspergillus fumigatus can produce the highest known number of meiotic crossovers.

Sexual reproduction involving meiosis is essential in most eukaryotes. This produces offspring with novel genotypes, both by segregation of parental chromosomes as well as crossovers between homologous chromosomes. A sexual cycle for the opportunistic human pathogenic fungus Aspergillus fumigatus is known, but the genetic consequences of meiosis have remained unknown.

Allorecognition genes drive reproductive isolation in Podospora anserina.

Allorecognition, the capacity to discriminate self from conspecific non-self, is a ubiquitous organismal feature typically governed by genes evolving under balancing selection. Here, we show that in the fungus Podospora anserina, allorecognition loci controlling vegetative incompatibility (het genes), define two reproductively isolated groups through pleiotropic effects on sexual compatibility. These two groups emerge from the antagonistic interactions of the unlinked loci het-r (encoding a NOD-like receptor) and het-v (encoding a methyltransferase and an MLKL/HeLo domain protein).

Flower Bulb Waste Material is a Natural Niche for the Sexual Cycle in .

With population genetic evidence of recombination ongoing in the natural population and a sexual cycle demonstrated in the laboratory the question remained what the natural niche for sex is. Composting plant-waste material is a known substrate of to thrive and withstand temperatures even up to 70°C. Previous studies have shown indirect evidence for sexual reproduction in these heaps but never directly demonstrated the sexual structures due to technical limitations.