Biology subjects

Merenyi, Z.

Publications and source records attributed to Merenyi, Z..

13 recordsLinked to original sources

bioRxiv2026

Functionally dark genes and the transcriptomic landscape of sporulation in a model mushroom-forming fungus

Spores are the primary means of fungal reproduction, contributing to genetic diversity, colonization, and adaptation. Although spore formation is a pivotal part of the fungal life cycle, its genetic underpinnings remain poorly known. In this study, we characterize transcriptomic changes from late meiosis to early basidiospore formation in the mushroom-forming fungus Coprinopsis cinerea, decipher several cellular processes, and identify novel genes involved in this process. We identify distinct trajectories of gene expression, each of which display different functional signals, corresponding to meiotic and morphogenetic processes and transitions between these. Our analyses identify diverse arrays of fungal cell wall modifying carbohydrate-active enzymes, ferritins, a putative catechol-melanin synthesis pathway, as well as components of the mitotic/meiotic apparatus. We present twelve highly conserved genes with roles specific to sexual sporulation in both budding yeast and C. cinerea, indicating deep conservation of the gene networks driving sexual spore formation. Reverse genetics identified three conserved but functionally poorly characterized genes conferring sporeless and spore-poor phenotypes that result from postmeiotic developmental arrests stemming from spore inflation and nuclear migration problems. Overall, this study provides novel insight into basidiomycete spore formation and highlights the cornucopia of novel functions encoded by functionally dark genes.

microbiology↗

bioRxiv2025

Functional characterization of a Con7-related transcription factor in Coprinopsis cinerea indicates evolutionary conservation of morphogenetic roles

Fruiting bodies of mushroom-forming fungi (Agaricomycetes) exhibit the highest degree of multicellular complexity in fungi, yet the molecular underpinnings of their developmental programs remain incompletely understood. Here, we characterize gcd1, a gene encoding a transcription factor in the Con7 subfamily of C2H2-type zinc finger proteins. This subfamily has previously been implicated in pathogenic morphogenesis in Ascomycota, but their role in Agaricomycetes has not previously been addressed. In Coprinopsis cinerea, CRISPR/Cas9-mediated deletion of gcd1 resulted in strains with severely impaired fruiting body morphogenesis, with malformed cap, stipe, and gill tissues. Gcd1 deletion strains lacked universal veil, resembling species with open (gymnocarpous) development. We find that GCD1/Con7 homologs are widely distributed in most Dikarya species and are mostly encoded by a single gene in each species genome. Transcriptome analyses identified several misregulated genes in the {Delta}gcd1 mutant, which pinpoint potential mechanisms underlying its developmental defects as well as provided insights into the morphogenesis of mushroom fruiting bodies. These findings establish GCD1 as a key regulator of multicellular development in C. cinerea and broaden the known functions of Con7-like transcription factors to include fruiting body morphogenesis in Agaricomycetes. Overall, our results and the morphogenetic role of Con7-like transcription factors of Ascomycota suggest functional conservation over half a billion years of evolution.

microbiology↗

bioRxiv2024

Unraveling Morphogenesis, Starvation, and Light Responses in a Mushroom-Forming Fungus, Coprinopsis cinerea, Using Long Read Sequencing and Extensive Expression Profiling

Mushroom-forming fungi (Agaricomycetes) are emerging as pivotal players in several fields, as drivers of nutrient cycling, sources of novel applications, and the group includes some of the most morphologically complex multicellular fungi. Genomic data for Agaricomycetes are accumulating at a steady pace, however, this is not paralleled by improvements in the quality of genome sequence and associated functional gene annotations, which leaves gene function notoriously poorly understood in comparison with other fungi and model eukaryotes. We set out to improve our functional understanding of the model mushroom Coprinopsis cinerea by integrating a new, chromosome-level assembly with high-quality gene predictions and functional information derived from gene-expression profiling data across 67 developmental, stress, and light conditions. The new annotation has considerably improved quality metrics and includes 5- and 3-untranslated regions (UTRs), polyadenylation sites (PAS), upstream ORFs (uORFs), splicing isoforms, conserved sequence motifs (e.g., TATA and Kozak boxes) and microexons. We found that alternative polyadenylation is widespread in C. cinerea, but that it is not specifically regulated across the various conditions used here. Transcriptome profiling allowed us to delineate core gene sets corresponding to carbon starvation, light-response, and hyphal differentiation, and uncover new aspects of the light-regulated phases of life cycle. As a result, the genome of C. cinerea has now become the most comprehensively annotated genome among mushroom-forming fungi, which will contribute to multiple rapidly expanding fields, including research on their life history, light and stress responses, as well as multicellular development.

genomics↗

bioRxiv2023

Snowball: a novel gene family required for developmental patterning in fruiting bodies of mushroom-forming fungi (Agaricomycetes)

The morphogenesis of sexual fruiting bodies of fungi is a complex process determined by a genetically encoded program. Fruiting bodies reached the highest complexity levels in the Agaricomycetes, yet, the underlying genetics is currently poorly known. In this work, we functionally characterized a highly conserved unannotated gene termed snb1, whose expression level increases rapidly during fruiting body initiation. According to phylogenetic analyses, orthologues of snb1 are present in almost all agaricomycetes and may represent a novel conserved gene family that plays a substantial role in fruiting body development. We disrupted snb1 using CRISPR/Cas9 in the agaricomycete model organism Coprinopsis cinerea. Snb1 deletion mutants formed unique, snowball-shaped, rudimentary fruiting bodies that could not differentiate caps, stipes and lamellae. We took advantage of this phenotype to study fruiting body differentiation using RNA-Seq analyses. This revealed differentially regulated genes and gene families that, based on wild-type RNA-Seq data, were upregulated early during development and showed tissue-specific expression, underscoring their potential role in differentiation. Taken together, the novel gene family of snb1 and the differentially expressed genes in the snb1 mutants provide valuable insights into the complex mechanisms underlying developmental patterning in the Agaricomycetes. ImportanceFruiting bodies of mushroom-forming fungi (Agaricomycetes) are complex multicellular structures, with a spatially and temporally integrated developmental program that is, however, currently poorly known. In this study we present a novel, conserved gene family, Snowball (snb), termed after the unique, differentiation-less fruiting body morphology of snb1 knockout strains in the model mushroom Coprinopsis cinerea. Snb is a hitherto unannotated gene that is highly conserved among agaricomycetes and encodes a protein of unknown function. A comparative transcriptomic analysis of the early developmental stages of differentiated wild-type and non-differentiated mutant fruiting bodies revealed conserved differentially expressed genes which may be related to tissue differentiation and developmental patterning fruiting body development.

developmental biology↗

bioRxiv2022

Purging genomes of contamination eliminates systematic bias from evolutionary analyses of ancestral genomes

Contamination of genomes and sequence databases is an increasingly recognized problem, however, efficient tools for removing alien sequences are still sparse and the impact of impure data on downstream analyses remains to be fully explored. Here, we present a new, highly sensitive tool, ContScout, for removing contamination from genomes, evaluate the level of contamination in 844 published eukaryotic genomes and show that contaminating proteins can severely impact analyses of genome evolution. Via benchmarking against synthetic data, we demonstrate that ContScout achieves high specificity and sensitivity when separating sequences of different high level taxa from each other. Furthermore, by testing on manually curated data we show that ContScout by far outperforms pre-existing tools. In the context of ancestral genome reconstruction, an increasingly common approach in evolutionary genomics, we show that contamination leads to spurious early origins for gene families and inflates gene loss rates several fold, leading to false notions of complex ancestral genomes. Using early eukaryotic ancestors (including LECA) as a test case, we assess the magnitude of bias and identify mechanistic bases of the estimation problems. Based on these results, we advocate the incorporation of contamination filtering as a routine step of reporting new draft genomes and caution against the outright interpretation of complex ancestral genomes and subsequent gene loss without accounting for contamination.

bioinformatics↗

bioRxiv2022

Taxonomic vs genomic fungi: contrasting evolutionary loss of protistan genomic heritage and emergence of fungal novelties

Fungi are among the most ecologically important heterotrophs that have radiated into most niches on Earth and fulfil key ecological services. However, despite intense interest in their origins, major genomic trends characterising the evolutionary route from a unicellular opisthokont ancestor to derived multicellular fungi remain poorly known. Here, we reconstructed gene family evolution across 123 genomes of fungi and relatives and show that a dominant trend in early fungal evolution has been the gradual shedding of protist genes and highly episodic innovation via gene duplication. We find that the gene content of early-diverging fungi is protist-like in many respects, owing to the conservation of protist genes in early fungi. While gene loss has been constant and gradual during early fungal evolution, our reconstructions show that gene innovation showed two peaks. Gene groups with the largest contribution to genomic change included extracellular proteins, transcription factors, as well as ones linked to the coordination of nutrient uptake with growth, highlighting the transition to a sessile osmotrophic feeding strategy and subsequent lifestyle evolution as important elements of early fungal evolution. Taken together, this work provided a highly resolved genome-wide catalogue of gene family changes across fungal evolution. This suggests that the genome of pre-fungal ancestors may have been transformed into the archetypal fungal genome by a combination of gradual gene loss, turnover and two large duplication events rather than by abrupt changes, and consequently, that the taxonomically defined fungal kingdom does not represent a genomically uniform assemblage of extant species characterized by diagnostic synapomorphies.

evolutionary biology↗

bioRxiv2022

Genomic innovation and horizontal gene transfer shaped plant colonization and biomass degradation strategies of a globally prevalent fungal pathogen

Members of the fungal genus Armillaria are necrotrophic pathogens with efficient plant biomass-degrading strategies. The genus includes some of the largest terrestrial organisms on Earth, spreading underground and causing tremendous losses in diverse ecosystems. Despite their global importance, the mechanism by which Armillaria evolved pathogenicity in a clade of dominantly non-pathogenic wood-degraders (Agaricales) remains elusive. Here, using new genomic data, we show that Armillaria species, in addition to widespread gene duplications and de novo gene origins, appear to have at least 775 genes that were acquired via 101 horizontal gene transfer (HGT) events, primarily from Ascomycota. Functional and expression data suggest that HGT might have affected plant biomass-degrading and virulence abilities of Armillaria, two pivotal traits in their lifestyle. We further assayed gene expression during root and cambium colonization, and report putative virulence factors, extensive regulation of horizontally acquired and wood-decay related genes as well as novel pathogenicity-induced small secreted proteins (PiSSPs). Two PiSSPs induced necrosis in live plants, suggesting they are potential virulence effectors conserved across Armillaria. Overall, this study details how evolution knitted together horizontally and vertically inherited genes in complex adaptive traits, such as plant biomass degradation and pathogenicity, paving the way for development of infection models for one of the most influential pathogens of temperate forest ecosystems.

genomics↗

bioRxiv2021

Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes

Fruiting bodies of mushroom-forming fungi (Agaricomycetes) are among the most complex structures produced by fungi. Unlike vegetative hyphae, fruiting bodies grow determinately and follow a genetically encoded developmental program that orchestrates tissue differentiation, growth and sexual sporulation. In spite of more than a century of research, our understanding of the molecular details of fruiting body morphogenesis is limited and a general synthesis on the genetics of this complex process is lacking. In this paper, we aim to comprehensively identify conserved genes related to fruiting body morphogenesis and distill novel functional hypotheses for functionally poorly characterized genes. As a result of this analysis, we report 921 conserved developmentally expressed gene families, only a few dozens of which have previously been reported in fruiting body development. Based on literature data, conserved expression patterns and functional annotations, we provide informed hypotheses on the potential role of these gene families in fruiting body development, yielding the most complete description of molecular processes in fruiting body morphogenesis to date. We discuss genes related to the initiation of fruiting, differentiation, growth, cell surface and cell wall, defense, transcriptional regulation as well as signal transduction. Based on these data we derive a general model of fruiting body development, which includes an early, proliferative phase that is mostly concerned with laying out the mushroom body plan (via cell division and differentiation), and a second phase of growth via cell expansion as well as meiotic events and sporulation. Altogether, our discussions cover 1480 genes of Coprinopsis cinerea, and their orthologs in Agaricus bisporus, Cyclocybe aegerita, Armillaria ostoyae, Auriculariopsis ampla, Laccaria bicolor, Lentinula edodes, Lentinus tigrinus, Mycena kentingensis, Phanerochaete chrysosporium, Pleurotus ostreatus, and Schizophyllum commune, providing functional hypotheses for [~]10% of genes in the genomes of these species. Although experimental evidence for the role of these genes will need to be established in the future, our data provide a roadmap for guiding functional analyses of fruiting related genes in the Agaricomycetes. We anticipate that the gene compendium presented here, combined with developments in functional genomics approaches will contribute to uncovering the genetic bases of one of the most spectacular multicellular developmental processes in fungi.

evolutionary biology↗

bioRxiv2021

Gene age predicts the transcriptional landscape of sexual morphogenesis in multicellular fungi

Multicellularity has been one of the most important innovations in the history of life. The role of regulatory evolution in driving transitions to multicellularity is being increasingly recognized; however, patterns and drivers of transcriptome evolution are poorly known in many clades. We here reveal that allele-specific expression, natural antisense transcripts and developmental gene expression, but not RNA editing or a developmental hourglass act in concert to shape the transcriptome of complex multicellular fruiting bodies of fungi. We find that transcriptional patterns of genes are strongly predicted by their evolutionary age. Young genes showed more expression variation both in time and space, possibly because of weaker evolutionary constraint, calling for partially non-adaptive interpretations of evolutionary changes in the transcriptome of multicellular fungi. Gene age also correlated with function, allowing us to separate fruiting body gene expression related to simple sexual development from that potentially underlying complex morphogenesis. Our study highlighted a transcriptional complexity that provides multiple speeds for transcriptome evolution, but also that constraints associated with gene age shape transcriptomic patterns during transitions to complex multicellularity in fungi.

evolutionary biology↗

bioRxiv2020

Hallmarks of basidiomycete soft- and white-rot in wood-decay -omics data of Armillaria

The genus Armillaria spp. (Fungi, Basidiomycota) includes devastating pathogens of temperate forests and saprotrophs that decay wood. Pathogenic and saprotrophic Armillaria species can efficiently colonize and decay woody substrates, however, mechanisms of wood penetration and colonization are poorly known. We assayed the colonization and decay of autoclaved spruce roots using the conifer-specialists Armillaria ostoyae and A. cepistipes using transcriptomic and proteomic data. Transcript and protein levels were altered more extensively in the saprotrophic A. cepistipes than in the pathogenic A. ostoyae and in invasive mycelia of both species compared to their rhizomorphs. Diverse suites of carbohydrate-active enzyme genes (CAZymes), in particular pectinolytic ones and expansins, were upregulated in both species, whereas ligninolytic genes were mostly downregulated. Our gene expression data, together with previous comparative genomic and decay-chemistry analyses suggest that wood decay by Armillaria differs from that of typical white-rot fungi and shows features resembling soft rot. We propose that Armillaria species have modified the ancestral white-rot machinery so that it allows for selective ligninolysis based on environmental conditions and/or host types.

ecology↗

bioRxiv2019

Unmatched level of molecular convergence among deeply divergent complex multicellular fungi

Convergent evolution is pervasive in nature, but it is poorly understood how various constraints and natural selection limit the diversity of evolvable phenotypes. Here, we report that, despite >650 million years of divergence, the same genes have repeatedly been co-opted for the development of complex multicellularity in the two largest clades of fungi--the Ascomycota and Basidiomycota. Co-opted genes have undergone duplications in both clades, resulting in >81% convergence across shared multicellularity-related families. This convergence is coupled with a rich repertoire of multicellularity-related genes in ancestors that predate complex multicellular fungi, suggesting that the coding capacity of early fungal genomes was well suited for the repeated evolution of complex multicellularity. Our work suggests that evolution may be predictable not only when organisms are closely related or are under similar selection pressures, but also if the genome biases the potential evolutionary trajectories organisms can take, even across large phylogenetic distances.

evolutionary biology↗

bioRxiv2019

Comparative genomics reveals the origin of fungal hyphae and multicellularity

Hyphae represent a hallmark structure of multicellular fungi with immense importance in their life cycle, including foraging for nutrients, reproduction, or virulence. Hypha morphogenesis has been the subject to intense interest, yet, the origins and genetic underpinning of the evolution of hyphae are hardly known. Using comparative genomics, we here show that the emergence of hyphae correlates with multiple types of genetic changes, including alterations of gene structure, gene family diversification as well as co-option and exaptation of ancient eukaryotic genes (e.g. phagocytosis-related genes). Half of the gene families involved in hypha morphogenesis have homologs in unicellular fungi and non-fungal eukaryotes and show little or no duplications coincident with the origin of multicellular hyphae. Considerable gene family diversification was observed only in transcriptional regulators and genes related to cell wall synthesis and modification. Despite losing 35-46% of their genes, yeasts retained significantly more multicellularity-related genes than expected by chance. We identified 414 gene families that evolved in a correlated fashion with hyphal multicellularity and may have contributed to its evolution. Contrary to most multicellular lineages, the origin of hyphae did not correlate with the expansion of gene families encoding kinases, receptors or adhesive proteins. Our analyses suggest that fungi took a unique route to multicellularity that involved limited gene family diversification and extensive co-option of ancient eukaryotic genes.

evolutionary biology↗

bioRxiv2018

Transcriptomic atlas of mushroom development highlights an independent origin of complex multicellularity

We constructed a reference atlas of mushroom formation based on developmental transcriptome data of six species and comparisons of >200 whole genomes, to elucidate the core genetic program of complex multicellularity and fruiting body development in mushroom-forming fungi (Agaricomycetes). Nearly 300 conserved gene families and >70 functional groups contained developmentally regulated genes from five to six species, covering functions related to fungal cell wall (FCW) remodeling, targeted protein degradation, signal transduction, adhesion and small secreted proteins (including effector-like orphan genes). Several of these families, including F-box proteins, protein kinases and cadherin-like proteins, showed massive expansions in Agaricomycetes, with many convergently expanded in multicellular plants and/or animals too, reflecting broad genetic convergence among independently evolved complex multicellular lineages. This study provides a novel entry point to studying mushroom development and complex multicellularity in one of the largest clades of complex eukaryotic organisms.

evolutionary biology↗