Publications by authors named "Jaqueline Hess"

Article Synopsis
  • The subgenus Tillandsia is part of a rapidly evolving group of plants known for their unique water-saving adaptation called Crassulacean acid metabolism (CAM), which has independently evolved in various plant families.
  • Researchers analyzed the genomes of two Tillandsia species with different photosynthetic traits to understand how CAM evolved, discovering that significant genomic rearrangements and a dynamic landscape of transposable elements influenced their genomes.
  • The study found that changes in how photosynthesis is regulated played a key role in CAM evolution, with certain significant gene families expanding in the species that use CAM, although the actual DNA sequences of these genes weren't under strong selection pressure.
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Global change is reshaping Earth's biodiversity, but the changing distributions of nonpathogenic fungi remain largely undocumented, as do mechanisms enabling invasions. The ectomycorrhizal Amanita phalloides is native to Europe and invasive in North America. Using population genetics and genomics, we sought to describe the life history traits of this successfully invading symbiotic fungus.

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Article Synopsis
  • Canonical sexual reproduction in basidiomycete fungi usually involves the fusion of two haploid individuals, resulting in a genetically diverse mycelial body, but some mushrooms, like Amanita phalloides, can reproduce without mating.
  • Population genomics reveal that both homokaryotic (single nucleus) and heterokaryotic (multiple nuclei) mushrooms coexist in California, indicating that the nuclei of homokaryotic mushrooms can contribute to outcrossing.
  • The study shows that death cap mushrooms have a unique mating type control and can reproduce both alone and with others, enabling their rapid spread in new environments over the past 17 to 30 years.
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Speciation, the continuous process by which new species form, is often investigated by looking at the variation of nucleotide diversity and differentiation across the genome (hereafter genomic landscapes). A key challenge lies in how to determine the main evolutionary forces at play shaping these patterns. One promising strategy, albeit little used to date, is to comparatively investigate these genomic landscapes as progression through time by using a series of species pairs along a divergence gradient.

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Canonical sexual reproduction among basidiomycete fungi involves the fusion of two haploid individuals of different sexes, resulting in a heterokaryotic mycelial body made up of genetically different nuclei . Using population genomics data, we discovered mushrooms of the deadly invasive are also homokaryotic, evidence of sexual reproduction by single individuals. In California, genotypes of homokaryotic mushrooms are also found in heterokaryotic mushrooms, implying nuclei of homokaryotic mycelia also promote outcrossing.

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Target capture has emerged as an important tool for phylogenetics and population genetics in nonmodel taxa. Whereas developing taxon-specific capture probes requires sustained efforts, available universal kits may have a lower power to reconstruct relationships at shallow phylogenetic scales and within rapidly radiating clades. We present here a newly developed target capture set for Bromeliaceae, a large and ecologically diverse plant family with highly variable diversification rates.

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Climate change causes increased tree mortality leading to canopy loss and thus sun-exposed forest floors. Sun exposure creates extreme temperatures and radiation, with potentially more drastic effects on forest organisms than the current increase in mean temperature. Such conditions might potentially negatively affect the maturation of mushrooms of forest fungi.

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Globalization and international trade have impacted organisms around the world leading to a considerable number of species establishing in new geographic areas. Many organisms have taken advantage of human-made environments, including buildings. One such species is the dry rot fungus Serpula lacrymans, which is the most aggressive wood-decay fungus in indoor environments in temperate regions.

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Ecological niche breadth and the mechanisms facilitating its evolution are fundamental to understanding adaptation to changing environments, persistence of generalist and specialist lineages and the formation of new species. Woody substrates are structurally complex resources utilized by organisms with specialized decay machinery. Wood-decaying fungi represent ideal model systems to study evolution of niche breadth, as they vary greatly in their host range and preferred decay stage of the substrate.

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By introducing novel capacities and functions, new genes and gene families may play a crucial role in ecological transitions. Mechanisms generating new gene families include de novo gene birth, horizontal gene transfer, and neofunctionalization following a duplication event. The ectomycorrhizal (ECM) symbiosis is a ubiquitous mutualism and the association has evolved repeatedly and independently many times among the fungi, but the evolutionary dynamics enabling its emergence remain elusive.

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Article Synopsis
  • - The Bromeliaceae family, particularly the genus Tillandsia, has undergone significant diversification due to key innovations like the shift from C to CAM photosynthesis, which helps adaptations to dry environments.
  • - Researchers used phylogenomic techniques and RNA sequencing to explore how these photosynthetic changes are linked to other adaptations for surviving in xeric conditions, including genetic and metabolic shifts.
  • - Findings indicate that the evolution of CAM involved the expansion of certain genes related to growth regulation and the reprogramming of stress response genes, providing insight into how these adaptive traits are repeatedly developed in this diverse plant group.
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Many recent studies have addressed the mechanisms operating during the early stages of speciation, but surprisingly few studies have tested theoretical predictions on the evolution of strong reproductive isolation (RI). To help address this gap, we first undertook a quantitative review of the hybrid zone literature for flowering plants in relation to reproductive barriers. Then, using as an exemplary model group, we analysed genome-wide variation for phylogenetic tree topologies in both early- and late-stage speciation taxa to determine how these patterns may be related to the genomic architecture of RI.

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The rhizosphere of plants is enriched in nutrients facilitating growth of microorganisms, some of which are recruited as endophytes. Endophytes, especially Actinobacteria, are known to produce a plethora of bioactive compounds. We hypothesized that subsp.

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The aim of this study was to investigate differential expression profiles of the brown rot fungus (previously ) harvested at several time points when grown on radiata pine () and radiata pine with three different levels of modification by furfuryl alcohol, an environmentally benign commercial wood protection system. The entire gene expression pattern of a decay fungus was followed in untreated and modified wood from initial to advanced stages of decay. The results support the current model of a two-step decay mechanism, with the expression of genes related to initial oxidative depolymerization, followed by an accumulation of transcripts of genes related to the hydrolysis of cell wall polysaccharides.

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The basidiomycete Chondrostereum purpureum (Silverleaf fungus) is a saprotroph and plant pathogen commercially used for combatting forest "weed" trees in vegetation management. However, little is known about its lignocellulose-degrading capabilities and the enzymatic machinery that is responsible for the degradative potential, and it is not yet clear to which group of wood-rot fungi it actually belongs. Here, we sequenced and analyzed the draft genome of C.

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Article Synopsis
  • This research focuses on understanding genetic diversification in palms, an important plant family, using advanced whole genome sequencing to create molecular markers for better studies at various evolutionary levels.
  • The study developed a comprehensive set of genomic markers covering 4,184 regions, including genes and neutral areas, designed to avoid issues like copy number variation, enabling analysis of evolutionary rates.
  • The newly created markers were tested across different palm sub-families, achieving high specificity and efficiency, which will enhance the analysis of genomic diversity and facilitate future research combining new and existing datasets.
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Fungi are evolutionary shape shifters and adapt quickly to new environments. Ectomycorrhizal (EM) symbioses are mutualistic associations between fungi and plants and have evolved repeatedly and independently across the fungal tree of life, suggesting lineages frequently reconfigure genome content to take advantage of open ecological niches. To date analyses of genomic mechanisms facilitating EM symbioses have involved comparisons of distantly related species, but here, we use the genomes of three EM and two asymbiotic (AS) fungi from the genus Amanita as well as an AS outgroup to study genome evolution following a single origin of symbiosis.

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In the version of this Article originally published, it was incorrectly stated that "16,687 protein-coding genes were inferred for the most recent common ancestor (MRCA) of Armillaria"; the value was incorrect and it should have read "15,787". This has now been corrected.

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Armillaria species are both devastating forest pathogens and some of the largest terrestrial organisms on Earth. They forage for hosts and achieve immense colony sizes via rhizomorphs, root-like multicellular structures of clonal dispersal. Here, we sequenced and analysed the genomes of four Armillaria species and performed RNA sequencing and quantitative proteomic analysis on the invasive and reproductive developmental stages of A.

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To elucidate the genetic bases of mycorrhizal lifestyle evolution, we sequenced new fungal genomes, including 13 ectomycorrhizal (ECM), orchid (ORM) and ericoid (ERM) species, and five saprotrophs, which we analyzed along with other fungal genomes. Ectomycorrhizal fungi have a reduced complement of genes encoding plant cell wall-degrading enzymes (PCWDEs), as compared to their ancestral wood decayers. Nevertheless, they have retained a unique array of PCWDEs, thus suggesting that they possess diverse abilities to decompose lignocellulose.

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Article Synopsis
  • The genus Amanita includes both symbiotic fungi that can’t break down plant cell walls and asymbiotic decomposers that can.
  • The carbohydrate esterases family 1 (CE1s) are key enzymes involved in carbon metabolism, and research shows CE1 genes in the symbiotic A. muscaria are more closely related to bacteria than to other fungi, indicating a horizontal gene transfer event.
  • The differences in CE1 genes between symbiotic and asymbiotic Amanita suggest that HGT may lead to new metabolic functions or roles in signaling and defense, marking the first evidence of gene transfer affecting carbohydrate metabolism in ectomycorrhizal fungi.
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Transposable elements (TEs) are ubiquitous inhabitants of eukaryotic genomes and their proliferation and dispersal shape genome architectures and diversity. Nevertheless, TE dynamics are often explored for one species at a time and are rarely considered in ecological contexts. Recent work with plant pathogens suggests a link between symbiosis and TE abundance.

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Phylogenomic approaches to the resolution of inter-species relationships have become well established in recent years. Often these involve concatenation of many orthologous genes found in the respective genomes followed by analysis using standard phylogenetic models. Genome-scale data promise increased resolution by minimising sampling error, yet are associated with well-known but often inappropriately addressed caveats arising through data heterogeneity and model violation.

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