Fine-scale genetic analyses reveal unexpected spatial-temporal heterogeneity in two natural populations of the commercial mushroom Agaricus bisporus

Abstract

This study examined the fine-scale genetic variation of the commercial mushroom, Agaricus bisporus, over 2 years at two sites in France. One site was a meadow fertilized with horse manure and disturbed regularly by humans ; the other was a Monterey cypress forest free of human disturbance. Altogether, 50 mushrooms were collected and analysed for mitochondrial and nuclear genetic variation marked by RFLPs and multilocus enzyme electrophoretic polymorphisms. Population samples from these two sites were genetically different and both sites contained high levels of genetic diversity. No identical genotypes were found at either site between the 2 years and there was little evidence for extensive vegetative clonality for this species. Contrary to expectations, very limited evidence of pseudohomothallic reproduction was found. Results from tests of Hardy-Weinberg equilibrium and genotypic equilibrium showed that outcrossing and recombination have played significant roles in both populations. The results demonstrated spatialtemporal genetic heterogeneity of A. bisporus in natural populations.

Molecular Epidemiology of White Pine Blister Rust: Recombination and Spatial Distribution

“…In Agaricus bisporus, another basidiomycete, spatial genetic heterogeneity was observed and no identical genotypes were found in two natural populations over 2 years of survey (55). By contrast, repeated asexual cycles or restricted dispersal would be expected to produce local genetic drift, linkage disequilibrium, or genotype clustering.…”

Diversity in the ability of Agaricus bisporus wild isolates to fruit at high temperature (25°C)

“…Indeed, FHT is not a discrete trait and, therefore, its genetic determinism is unlikely monogenic. Xu et al (2002) reported that all fruiting bodies isolated from each of two sample locations, Dinard and Gradignan (sites 24 and 13 in the present work), were genetically unique. This diversity and the conclusion that the FHT þ ability is not a fixed trait in the variety bisporus agree with the absence of correlation between geographical parameters and the FHT þ ability, leading to the collect of both FHT þ and FHT À isolates at a single site on a single day.…”

Alien fungal species distribution: the study case of Favolaschia calocera

“…F. calocera is suspected of performing one out of these two selfing reproductive strategies on the basis of the following evidence: (1) its ability to produce fertile basidiomes starting from monosporic cultures (the socalled phenomenon of monosporic fruiting), as indicated by Johnston et al (2006); (2) the presence of bisporic basidia without clamp connections (Heim 1945;Singer 1974;Vizzini and Zotti 2002;Johnston et al 2006); (3) low rates of ITS variations for both inter Italian strains and among these and extraeuropean ones. It is well known that in some fungi, successive generations of selfing, on a long-term scale, should generate persistent pseudoclonal lineages (Kerrigan 1990;Taylor et al 1999;Xu et al 2002).…”