Biology subjects

Vidal-Diez de Ulzurrun, G.

Publications and source records attributed to Vidal-Diez de Ulzurrun, G..

7 recordsLinked to original sources

bioRxiv2026

Nutrient and prey-sensing signaling pathways converge on the sphingolipid methyltransferase SMT1 to regulate trap formation in a predatory fungus

The nematode trapping fungus Arthrobotrys oligospora transitions from saprophytic growth to a predatory lifestyle by forming adhesive traps in response to nutrient limitation and nematode derived cues. How nutrient availability integrates with prey sensing to control trap formation remains unclear. The presence of glucose can suppress trap formation and we found that Cre1, a conserved transcription factor that regulates the carbon catabolite repression pathway in fungi is essential for trap formation. Comparative transcriptomics and functional studies identified SMT1, which encodes a sphingolipid C9 methyltransferase, as a Cre1-dependent target that is sufficient to restore trap formation defect in the cre1 mutant. Smt1 contributes to the formation of sterol-enriched membrane domain at the tip of a growing trap hyphae and thus affects trap morphogenesis. We further discovered that the expression of SMT1 depends on both Cre1 and another transcription factor Ste12 that acts downstream of the pheromone response MAPK pathway critical for prey-sensing. These findings reveal functional crosstalk between Cre1 and Ste12 where both transcription factors are required for the expression of SMT1 and demonstrate that a predatory fungus integrates nutrient and prey-derived signals to regulate predatory lifestyle switching.

microbiology↗

bioRxiv2025

Establishment of a Congenic Strain for the Oyster mushroom reveals the Structure and Evolution of Mating-Type Loci

Pleurotus ostreatus, a widely cultivated edible oyster mushroom, is an ecologically versatile species with applications in biotechnology, agriculture, and food production. It functions as a decomposer and in nutrient-limited conditions it enhances its survival by using a potent toxin to prey on nematodes. Its adaptability is further regulated by sexual reproduction, which follows a tetrapolar mating system governed by two unlinked, multiallelic loci, matA and matB. The two mating-compatible monokaryotic strains PC9 and PC15, derived from the parental dikaryon strain N001, exhibit significant physiological differences. PC9 grows robustly in laboratory conditions, whereas PC15 grows more slowly, making PC9 the preferred strain for research. To advance P. ostreatus as a genetic model, we characterized the mating-type (MAT) loci of both monokaryon strains and developed a congenic strain. We analyzed the MAT loci in multiple P. ostreatus strains, and identified 11 A and 12 B alleles among twelve haplotypes, confirming their multiallelic nature. Using genetic backcrosses, we introgressed the matA and matB loci from PC15 into the PC9 genetic background to generate the congenic strain PC9.15. After sequencing and assembling a high-quality and contiguous genome for PC9.15, we confirmed that the genomes of PC9.15 and PC9 are 99% similar, with the only major difference placed at the matA and matB loci. Author SummaryMushrooms are not just decomposers-they can also be predators. The oyster mushroom Pleurotus ostreatus is an ecologically adaptable species that thrives by breaking down plant material and preying on nematodes using a potent toxin that triggers rapid paralysis of nematode prey. In addition to its ability to switch from saprophyte to predator, another feature contributing to the ecological success of Pleurotus is its reproductive strategy. P. ostreatus reproduces sexually through a tetrapolar mating-type system, governed by two unlinked mating loci, matA and matB. These loci determine mating compatibility and contribute to genetic diversity, yet their precise structure and allelic diversity remain unclear. In this study, we characterized the matA and matB loci in P. ostreatus strains PC9 and PC15 and analyzed MAT loci across multiple strains, confirming their multiallelic nature. To enhance P. ostreatus as a genetic model, we developed the congenic strain PC9.15 by introgressing MAT alleles from PC15 into the PC9 genetic background through genetic backcrosses. Genome sequencing confirmed that PC9.15 closely matches the genome of PC9, except at the MAT loci. This study expands our understanding of mating-type diversity in P. ostreatus, introduces PC9.15 as a valuable tool for genetic studies and controlled crosses, and facilitates the development of P. ostreatus as a model system for fungal biology.

genetics↗

bioRxiv2020

Forward genetic screens identified mutants with defects in trap morphogenesis in the nematode-trapping fungus Arthrobotrys oligospora

Nematode-trapping fungi (NTF) are carnivorous fungi that prey on nematodes under nutrient-poor conditions via specialized hyphae that function as traps. The molecular mechanisms involved in the interactions between nematode-trapping fungi and their nematode prey are largely unknown. In this study, we conducted forward genetic screens to identify potential genes and pathways that are involved in trap morphogenesis and predation in the NTF Arthrobotrys oligospora. Using Ethyl methanesulfonate and UV as the mutagens, we generated 5552 randomly-mutagenized A. oligospora strains and identified 15 mutants with strong defects in trap morphogenesis. Whole genome sequencing and bioinformatic analyses revealed mutations in genes with roles in signaling, transcription or membrane transport that may contribute to the defects of trap morphogenesis in these mutants. We further conducted functional analyses on a candidate gene, YBP-1, and demonstrate that mutation of that gene was causative of the phenotypes observed in one of the mutants. The methods established in this study might provide helpful insights for establishing forward genetic screening methods for other non-model fungal species.

molecular biology↗

bioRxiv2020

Genome sequence of the oyster mushroom Pleurotus ostreatus strain PC9

The oyster mushroom Pleurotus ostreatus is a basidiomycete commonly found in the rotten wood and it is one of the most cultivated edible mushrooms globally. P. ostreatus is also a carnivorous fungus, which can paralyze and kill nematodes within minutes. However, the molecular mechanisms of the predator-prey interactions between P. ostreatus and nematodes remain unclear. PC9 and PC15 are two model strains of P. ostreatus and the genomes of both strains have been sequenced and deposited at the Joint Genome Institute (JGI). These two monokaryotic strains exhibit dramatic differences in growth, but because PC9 grows more robustly in laboratory conditions, it has become the strain of choice for many studies. Despite the fact that PC9 is the common strain for investigation, its genome is fragmentary and incomplete relative to that of PC15. To overcome this problem, we used PacBio long reads and Illumina sequencing to assemble and polish a more integrated genome for PC9. Our PC9 genome assembly, distributed across 17 scaffolds, is highly contiguous and includes six telomere-to-telomere scaffolds, dramatically improving the genome quality. We believe that our PC9 genome resource will be useful to the fungal research community investigating various aspects of P. ostreatus biology.

genomics↗

bioRxiv2020

Genomic analyses of two Italian oyster mushroom Pleurotus pulmonarius strains

Pleurotus mushrooms are among the most cultivated fungi in the world and are highly valuable for food, medicine and biotechnology industries. Furthermore, Pleurotus species are carnivorous fungi; they can rapidly paralyze and kill nematodes when nutrient-deprived. The predator-prey interactions between Pleurotus and nematodes are still widely unexplored. Moreover, the molecular mechanisms and the genes involved in the carnivorous behavior of Pleurotus mushrooms remain a mystery. We are attempting to understand the interactions between Pleurotus mushrooms and their nematode prey through genetic and genomic analyses. Two single spores (ss2 and ss5) isolated from a fruiting body of Pleurotus pulmonarius exhibited significant differences in growth and toxicity against nematodes. Thus, using PacBio long reads, we assembled and annotated two high-quality genomes for these two isolates of Pleurotus pulmonarius. Each of these assemblies contains 23 scaffolds, including 6 (ss2) and 8 (ss5) telomere-to-telomere scaffolds, and they are among the most complete assembled genomes of the Pleurotus species. Comparative analyses identified the genomic differences between the two P. pulmonarius strains. In sum, this work provides a genomic resource that will be invaluable for better understanding the Italian oyster mushroom P. pulmonarius.

genomics↗

bioRxiv2019

Natural diversity in the predatory behavior facilitates the establishment of a new robust model strain for nematode-trapping fungi

Nematode-trapping fungi (NTF) are a group of specialized microbial predators that consume nematodes when food sources are limited. Predation is initiated when conserved nematode ascaroside pheromones are sensed, followed by the development of complex trapping devices. To gain insights into the co-evolution of this inter-kingdom predator-prey relationship, we investigated natural populations of nematodes and NTF, that we found to be ubiquitous in soils. Arthrobotrys species were sympatric with various nematode species and behaved as generalist predators. The ability to sense prey amongst wild isolates of A. oligospora varied greatly, as determined by the number of traps after exposure to Caenorhabditis elegans. While some strains were highly sensitive to C. elegans and the nematode pheromone ascarosides, others responded only weakly. Furthermore, strains that were highly sensitive to the nematode prey also developed traps faster. The polymorphic nature of trap formation correlated with competency in prey killing, as well as with the phylogeny of A. oligospora natural strains, calculated after assembly and annotation of the genomes of twenty isolates. A chromosome level genome assembly and annotation was established for one of the most sensitive wild isolate, and deletion of the only G protein {beta} subunit-encoding gene of A. oligospora nearly abolished trap formation, implicating G protein signaling in predation. In summary, our study establishes a highly responsive A. oligospora wild isolate as a novel model strain for the study of fungal-nematode interactions and demonstrates that trap formation is a fitness character in generalist predators of the NTF family. Significance statementNematode-trapping fungi (NTF) are carnivorous microbes that hold potential to be used as biological control agents due to their ability to consume nematodes. In this work we show that NTF are ubiquitous generalist predators found in sympatry with their prey in soil samples. Wild isolates of NTF displayed a naturally diverse ability to execute their predatory lifestyle. We generated a large whole genome sequencing dataset for many of the fungal isolates that will serve as the basis of future projects isolates. In particular, we establish TWF154, a highly responsive strain of Arthrobotrys oligospora, as a model strain to study the genetics of NTF. Lastly, we provide evidence that G-protein signaling is necessary for trap induction in NTF.

molecular biology↗

bioRxiv2019

Fungal Feature Tracker (FFT): A tool for quantitatively characterizing the morphology and growth of filamentous fungi

Filamentous fungi are ubiquitous in nature and serve as important biological models in various scientific fields including genetics, cell biology, ecology, evolution, and chemistry. A significant obstacle in studying filamentous fungi is the lack of tools for characterizing their growth and morphology in an efficient and quantitative manner. Consequently, assessments of the growth of filamentous fungi are often subjective and imprecise. In order to remedy this problem, we developed Fungal Feature Tracker (FFT), a user-friendly software comprised of different image analysis tools to automatically quantify different fungal characteristics, such as spore number, spore morphology, and measurements of total length, number of hyphal tips and the area covered by the mycelium. In addition, FFT can recognize and quantify specialized structures such as the traps generated by nematode-trapping fungi, which could be tuned to quantify other distinctive fungal structures in different fungi. We present a detailed characterization and comparison of a few fungal species as a case study to demonstrate the capabilities and potential of our software. Using FFT, we were able to quantify various features at strain and species level, such as mycelial growth over time and the length and width of spores, which would be difficult to track using classical approaches. In summary, FFT is a powerful tool that enables quantitative measurements of fungal features and growth, allowing objective and precise characterization of fungal phenotypes.\n\nAuthor SummaryOne of the main obstacles to study filamentous fungi is the lack of tools for characterizing fungal phenotypes in an efficient and quantitative manner. Assessment of cell growth and numbers rely on tedious manual techniques that often result in subjective and imprecise measurements. In response to those limitations, we developed Fungal Feature Tracker (FFT), a user-friendly software that allows researchers to characterize different phenotypic features of filamentous fungi such as sporulation, spore morphology and mycelial growth. In addition, FFT can recognize and quantify other fungal structures including the fungal traps developed by nematode-trapping fungi. In order to show the capabilities and potential of our software, we conducted a detailed characterization and comparison of different fungal species. Our comparison relies on a series of experimental set-ups using standard and easily accessible equipment to ensure reproducibility in other laboratories. In summary, FFT is an easy to use and powerful tool that can quantitatively characterize fungal morphology, cell number and quantitatively measures the filamentous growth, which will allow advance our understanding of the growth and biology of filamentous fungi.

cell biology↗