Author Correction: Hybridization is a recurrent evolutionary stimulus in wild yeast speciation.

The original version of the Supplementary Information associated with this Article contained errors in Supplementary Figures 2, 12, 20 and 22. The HTML has been updated to include a corrected version of the Supplementary Information; the original incorrect versions of these Figures can be found as Supplementary Information associated with this Correction.

Hybridization is a recurrent evolutionary stimulus in wild yeast speciation.

Hybridization can result in reproductively isolated and phenotypically distinct lineages that evolve as independent hybrid species. How frequently hybridization leads to speciation remains largely unknown. Here we examine the potential recurrence of hybrid speciation in the wild yeast Saccharomyces paradoxus in North America, which comprises two endemic lineages SpB and SpC, and an incipient hybrid species, SpC*.

Persistence of Resident and Transplanted Genotypes of the Undomesticated Yeast Saccharomyces paradoxus in Forest Soil.

One might expect yeasts in soil to be highly dispersed via water or insects, forming ephemeral, genetically heterogeneous populations subject to competition and environmental stochasticity. Here, we report persistence of genotypes of the yeast in space and time. Within 1 km in a mixed hardwood forest on scales from centimeters to tens of meters, we detected persistence over 3 years of native genotypes, identified by single nucleotide polymorphisms (SNPs) genome-wide, of the wild yeast growing around and Yeasts were recovered by enrichment in ethanol-containing medium, which measures only presence or absence, not abundance.

Richard Paul Korf (1925-2016).

"With poetry, the tune is in the words themselves-and once you begin to hear it, it will stay with you." Richard P. Korf, notes to his narration of John Brown's Body.

Fungus Causing White-Nose Syndrome in Bats Accumulates Genetic Variability in North America with No Sign of Recombination.

Emerging fungal diseases of wildlife are on the rise worldwide, and the white-nose syndrome (WNS) epidemic in North American bats is a catastrophic example. The causal agent of WNS is a single clone of the fungus . Early evolutionary change in this clonal population has major implications for disease ecology and conservation.

Population genomics reveals structure at the individual, host-tree scale and persistence of genotypic variants of the undomesticated yeast Saccharomyces paradoxus in a natural woodland.

Genetic diversity in experimental, domesticated and wild populations of the related yeasts, Saccharomyces cerevisiae and Saccharomyces paradoxus, has been well described at the global scale. We investigated the population genomics of a local population on a small spatial scale to address two main questions. First, is there genomic variation in a S.

The underlying structure of adaptation under strong selection in 12 experimental yeast populations.

The aims of this study were to determine (i) whether adaptation under strong selection occurred through mutations in a narrow target of one or a few nucleotide sites or a broad target of numerous sites and (ii) whether the programs of adaptation previously observed from three experimental populations were unique or shared among populations that underwent parallel evolution. We used archived population samples from a previous study, representing 500 generations of experimental evolution in 12 populations under strong selection, 6 populations in a high-salt environment and 6 populations in a low-glucose environment. Each set of six populations included four with sexual reproduction and two with exclusively asexual reproduction.

PRP8 inteins in species of the genus Botrytis and other ascomycetes.

The mobile elements termed inteins have a sporadic distribution in microorganisms. It is unclear how these elements are maintained. Inteins are intervening protein sequences that autocatalytically excise themselves from a precursor.

Evidence for a common toolbox based on necrotrophy in a fungal lineage spanning necrotrophs, biotrophs, endophytes, host generalists and specialists.

The Sclerotiniaceae (Ascomycotina, Leotiomycetes) is a relatively recently evolved lineage of necrotrophic host generalists, and necrotrophic or biotrophic host specialists, some latent or symptomless. We hypothesized that they inherited a basic toolbox of genes for plant symbiosis from their common ancestor. Maintenance and evolutionary diversification of symbiosis could require selection on toolbox genes or on timing and magnitude of gene expression.

Cellular effects and epistasis among three determinants of adaptation in experimental populations of Saccharomyces cerevisiae.

Epistatic interactions in which the phenotypic effect of an allele is conditional on its genetic background have been shown to play a central part in various evolutionary processes. In a previous study (J. B.

Exploring the evolutionary ecology of fungal endophytes in agricultural systems: using functional traits to reveal mechanisms in community processes.

All plants, including crop species, harbor a community of fungal endophyte species, yet we know little about the biotic factors that are important in endophyte community assembly. We suggest that the most direct route to understanding the mechanisms underlying community assembly is through the study of functional trait variation in the host and its fungal consortium. We review studies on crop endophytes that investigate plant and fungal traits likely to be important in endophyte community processes.

Determinants of divergent adaptation and Dobzhansky-Muller interaction in experimental yeast populations.

Divergent adaptation can be associated with reproductive isolation in speciation [1]. We recently demonstrated the link between divergent adaptation and the onset of reproductive isolation in experimental populations of the yeast Saccharomyces cerevisiae evolved from a single progenitor in either a high-salt or a low-glucose environment [2]. Here, whole-genome resequencing and comparative genome hybridization of representatives of three populations revealed 17 mutations, six of which explained the adaptive increases in mitotic fitness.

Genome-wide investigation of reproductive isolation in experimental lineages and natural species of Neurospora: identifying candidate regions by microarray-based genotyping and mapping.

Inherent incompatibilities between genetic components from genomes of different species may cause intrinsic reproductive isolation. In evolution experiments designed to instigate speciation in laboratory populations of the filamentous fungus Neurospora, we previously discovered a pair of incompatibility loci (dfe and dma) that interact negatively to cause severe defects in sexual reproduction. Here we show that the dfe-dma incompatibility also is a significant cause of genetic isolation between two naturally occurring species of Neurospora (N.

Single nucleotide polymorphism-based diagnostic system for crop-associated Sclerotinia species.

A molecular diagnostic system using single nucleotide polymorphisms (SNPs) was developed to identify four Sclerotinia species: S. sclerotiorum (Lib.) de Bary, S.

Evidence for alteration of fungal endophyte community assembly by host defense compounds.

* Plant defense compounds are common stressors encountered by endophytes. Fungi readily evolve tolerance to these compounds, yet few studies have addressed the influence of intraspecific variation in defense compound production on endophyte colonization. We compared the influence of defense compound production on the composition of fungal endophyte communities in replicated field experiments.

New Populations of Sclerotinia sclerotiorum from Lettuce in California and Peas and Lentils in Washington.

ABSTRACT Four populations of Sclerotinia sclerotiorum in North America were inferred previously, based on analyses of both rapidly evolving markers (DNA fingerprint and mycelial compatiblity), and multilocus DNA sequence spanning the range between fast and slow evolution. Each population was defined as an interbreeding unit of conspecific individuals sharing a common recent ancestor and arising in a unique evolutionary event. The present study applies this standard to extend characterization of S.

Divergent adaptation promotes reproductive isolation among experimental populations of the filamentous fungus Neurospora.

Background: An open, focal issue in evolutionary biology is how reproductive isolation and speciation are initiated; elucidation of mechanisms with empirical evidence has lagged behind theory. Under ecological speciation, reproductive isolation between populations is predicted to evolve incidentally as a by-product of adaptation to divergent environments. The increased genetic diversity associated with interspecific hybridization has also been theorized to promote the development of reproductive isolation among independent populations.

Marker stability throughout 400 days of in vitro hyphal growth in the filamentous ascomycete, Sclerotinia sclerotiorum.

The stability of routinely used, population genetic markers through approximately 1 year of continuous laboratory growth was investigated in the common, plant pathogentic ascomycete Sclerotinia sclerotiorum. Given reports of accelerated mutation rates at higher temperatures, both a permissive temperature, 22 degrees C, and a temperature at the high end of tolerance, 30 degrees C, were employed. Because mycelial growth rate was tracked among mitotic lineages established for each strain, a subsidiary objective was addressed, testing the stability of a 30 degrees C-competent phenotype.

Host-synthesized secondary compounds influence the in vitro interactions between fungal endophytes of maize.

Maize produces a suite of allelopathic secondary metabolites, the benzoxazinoids. 2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one and 2,4-dihydroxy-2H-1,4-benzoxazin-3-one reside as glucosides in plant tissue and spontaneously degrade to 6-methoxy-2-benzoxazolinone (MBOA) and 2-benzoxazolinone (BOA) upon plant cell disruption. Several maize-associated fungi in the genus Fusarium can metabolize MBOA and BOA.

Incipient speciation by divergent adaptation and antagonistic epistasis in yeast.

Establishing the conditions that promote the evolution of reproductive isolation and speciation has long been a goal in evolutionary biology. In ecological speciation, reproductive isolation between populations evolves as a by-product of divergent selection and the resulting environment-specific adaptations. The leading genetic model of reproductive isolation predicts that hybrid inferiority is caused by antagonistic epistasis between incompatible alleles at interacting loci.

An optimized method for mycelial compatibility testing in Sclerotinia sclerotiorum.

Classification of isolates into mycelial compatibility groups (MCGs) is used routinely in many laboratories as a quick marker for genotyping Sclerotinia sclerotiorum within populations. Scoring each new sample requires optimization of standardized conditions to support adequate growth of all paired isolates. Appropriate conditions for growth are especially important because diverse compatibility reactions are difficult to categorize and score (e.

Mechanisms of fungal speciation.

The objective of this review is to provide a synthesis of speciation theory, of what is known about mechanisms of speciation in fungi and from this, what is expected, and of ideas on how speciation can be elucidated in more fungal systems. The emphasis is on process rather than pattern. Phylogeographic studies in some groups, such as the agarics, demonstrate predominantly allopatric speciation, often through vicariance, as seen in many plants and animals.

Origins of host-specific populations of the blast pathogen Magnaporthe oryzae in crop domestication with subsequent expansion of pandemic clones on rice and weeds of rice.

Rice, as a widely and intensively cultivated crop, should be a target for parasite host shifts and a source for shifts to co-occurring weeds. Magnaporthe oryzae, of the M. grisea species complex, is the most important fungal pathogen of rice, with a high degree of host specificity.