Despite the inherent challenge of finding suitable mating partners, most eukaryotes use sexual reproduction to produce offspring endowed with increase genetic diversity and fitness. The persistence of...

NOD-like receptors (NLRs) are intracellular immune receptors that detect pathogen-associated cues and trigger defence mechanisms, including regulated cell death. In filamentous fungi, some NLRs mediat...

Here, using live-cell fluorescence imaging, we report the remarkable and complex behavior of male nuclei during sexual reproduction in the model fungus Podospora anserina. In particular, during their ...

Abstract. Recombination is advantageous over the long-term, as it allows efficient selection and purging deleterious mutations. Nevertheless, recombination

Recombination is advantageous over the long-term, as it allows efficient selection and purging deleterious mutations. Nevertheless, recombination suppression has repeatedly evolved in sex chromosomes and mating-type chromosomes. The evolutionary causes for recombination suppression and the proximal mechanisms preventing crossing overs are still poorly understood. Several hypotheses have recently been suggested based on theoretical models, and in particular, that divergence could accumulate neutrally around a sex-determining region and reduce recombination rates, a self-reinforcing process that could foster progressive extension of recombination suppression. The ascomycete fungus Podospora anserina is an excellent model for investigating these questions. A 0.8 Mb region around the mating-type locus is non-recombining, despite being collinear between the two mating types. This fungus is mostly selfing, so that strains are highly homozygous, except in the non-recombining region around the mating-type locus that displays differentiation between mating types. Here, we generated a mutant to test the hypothesis that sequence divergence alone is responsible for recombination cessation. We replaced the mat- idiomorph by the sequence of the mat+ idiomorph, to obtain a strain that is sexually compatible with the mat-reference strain and isogenic to this strain in the MAT-proximal region. Crosses showed that recombination was still suppressed in the MAT-proximal region in the mutant strains, indicating that other proximal mechanisms than inversions or mere sequence divergence are responsible for recombination suppression in this fungus. This finding suggests that selective mechanisms likely acted for suppressing recombination, as the neutral model does not seem to hold, at least in this fungus. ### Competing Interest Statement The authors have declared no competing interest.

Abstract. Fungi harbor diverse arrays of genes encoding NOD-like receptors (NLRs), key intracellular immune proteins found in plants, animals, and bacteria

The ability to generate high-quality fungal genomes brought with it new frontiers of scientific discovery and paved the way for answering outstanding biological mysteries. Recently, several independen...

Podospora anserina is a coprophilous ascomycete fungus that has been used as a model organism since the 1930s. It has been reported from numerous types of herbivore dung globally, but recent genetic a...

Podospora anserina is a coprophilous ascomycete fungus that has been used as a model organism since the 1930s. It has been reported from numerous types of herbivore dung globally, but recent genetic a...