Exploring causes and consequences of reproductive behavior in the fungal genus Neurospora

The fungal genus Neurospora comprises haploid species showing a wide range of reproductive strategies, from sexual self-incompatibility (heterothallism) to sexual self-compatibility (homothallism) and asexuality, i.e. dispersal through conidia. The ancestral reproductive state (heterothallic/homothallic) remains an issue of controversy in the fungal kingdom: inter-species comparisons of synteny along the mat locus, containing the genes controlling mating-type and vegetative compatibility, were recently proven to be a powerful means to elucidate this question.
In contrast to the well-studied heterothallic Neurospora crassa, the genome of which is available, numerous homothallic Neurospora taxa remain practically unknown, with only morphological descriptions and a few published gene sequences available. Here, we sequenced, using Illumina technology, the genomes of four self-compatible species of Neurospora and yielded draft assemblies of at least 20x coverage.

We were able to describe the extended structure of the mat locus and inspect the conservation of synteny across Neurospora and a related genus, Sordaria. Our analyses suggest that self-compatibility has evolved multiple times in Neurospora, from self-incompatible ancestors through unequal crossing-over events, additional losses of coding and non-coding regions and unknown events independent of the mat locus. Additional sequencing of targeted regions of interest is now planned for some of the homothallic species for which the draft assemblies provided fragmented scaffolds for the mat region.

No relevant conflicts of interest declared.