Biology subjects

Debets, A. J.

Publications and source records attributed to Debets, A. J..

3 recordsLinked to original sources

bioRxiv2026

Genetic Association of Somatic Incompatibility and NLR-like Protein Domains in Coprinopsis cinerea

In fungi, hyphal fusion is beneficial within an individual, but fusion between individuals comes with the risks of infection or exploitation. To manage this risk, fungi have developed mechanisms to restrict sustained fusion to be within a genetic individual, called allorecognition. In Ascomycete fungi, this recognition is based on allelic identity at several polymorphic allorecognition genes, often triggering cell death. However, the genetic basis of allorecognition is unknown in basidiomycetes, the clade that includes mushroom-forming fungi. Here, we map the first locus for this trait, which we call somA, in the mushroom-forming fungus Coprinopsis cinerea. We combined F1 offspring phenotypes with independent backcross lines to identify a region on chromosome 5 linked with the production of a barrage zone, a classic allorecognition phenotype. Fine-mapping of this region resulted in a region with a set of kinases and NACHT domain proteins, flanked by a leucine-rich repeat (LRR) protein. While the NACHT and kinase proteins are diverse between the parents, the LRR-encoding protein shows signs of purifying selection. Additional C. cinerea genomes show that this region contains several highly divergent alleles, consistent with long-term balancing selection. These polymorphic alleles all contain a single monomorphic LRR, which may indicate a novel mechanism for fungal nonself recognition. Based on a phylogenetic survey of related Basidiomycetes, this specific locus architecture appears to be restricted to closely related species. This finding of a multiallelic locus may explain the general trend of few nonself recognition loci in basidiomycetes. These results provide a first understanding of how individuality is maintained in basidiomycetes. Significance StatementHow mushroom-forming fungi recognize each other as individuals is an open question. Here, we identify the first genes that trigger this recognition in a mushroom-forming fungus. As these fungi have very distinctive lifecycles compared to mold-forming fungi, it was hypothesized that the process would operate from different mechanisms. Our results show the molecular mechanisms are in fact quite similar. These results provide a first step towards understanding how these fungi can both fuse with themselves and still discriminate against other individuals.

genetics↗

bioRxiv2026

Cheating (re)shapes pathogen virulence and antifungal resistance

Filamentous fungi grow as fused, multinucleate networks that share secreted public goods vs private goods. We asked whether this sharing enables "cheater" nuclei to increase in frequency by exploiting goods produced by other nuclei, and whether such social conflict shapes virulence and antifungal resistance. We tested this in the gray mold pathogen Botrytis cinerea by contrasting an extracellular detoxification trait, a public good (enzymatic hydrolysis of the tomato saponin alpha-tomatine) with an intracellular antibiotic resistance trait, a private good (hygromycin phosphotransferase). In pairwise competitions, tomatinase-deficient nuclei gained advantage when rare against a constitutive producer, both in vitro and in planta, even though producers drive lesion expansion. An ordinary differential equation model fitted to the competition outcomes identified antibiotic gradients as the key driver of frequency-dependent selection and predicted stable coexistence of producer and non-producer nuclei across multinucleate bottlenecks. Cheating within fungal syncytia can therefore decouple virulence from reproduction and buffer the selection on antifungal resistance.

genetics↗

bioRxiv2025

Genetic mapping and nuclear interactions of an incompatibility response in Agaricus bisporus

During cultivation, mixing of different heterokaryotic individuals of the button mushroom, Agaricus bisporus, generally reduces yield. This phenomenon could be caused by direct antagonistic responses and/or reduced synchronization by not forming a chimeric hyphal network. In other fungi, highly divergent alleles for a set of genes affect successful network formation between individuals either by preventing fusion or, more commonly, triggering cell death post-fusion. To understand this process in A. bisporus, it is important to identify the allelic variants allowing these fungi to discriminate self from nonself. We leverage a recently described cell death staining method utilizing Evans Blue to visualize mycelial compatibility. Here, we provide results of a first genetic mapping of incompatibility alleles in A. bisporus. Crossing strains between A. bisporus var. bisporus and A. bisporus var. burnetti we find segregation ratios of compatible progeny generally consistent with three nuclear loci. To identify these regions, we first use a set of single Chromosome Substitution Lines (CSLs), produced by genotyping progeny with recombination skewed to the very chromosome ends. We localize the main effect to be between two and three chromosomes, depending on the common nucleus of interacting heterokaryons. Using genome-wide markers for 167 sexual progeny, we identify loci controlling mycelial compatibility on chromosomes 4, 6 and 7, the same chromosomes as indicated by chromosome substitution lines. Notably, while the choice of a common nucleus seemed to affect the compatibility of CSLs, it did not seem to affect the loci identified in the sexual progeny. The ability to mix different strains of this mushroom-forming fungus could allow additional cultivation approaches, combining strains with complementary characteristics. These results provide a starting point towards understanding the molecular mechanisms underlying this fundamental property of hyphal networks in basidiomycetes.

genetics↗