Top: Micrographs showing hyphal filaments extending from colony peripheries in a sexual cross between CBS8507 and CBS10435 after 2 weeks of incubation on CMA and V8 pH 5 media, in the dark, at room temperature. Insets depict two types of basidia: globose (a–c) and lageniform (b–d). Black arrows indicate clusters of cells emerging near basidia (either at the surface or embedded), scored as potential meiotic progeny (basidiospores). Bottom: Schematic representation of key chromosomal rearrangements and evolutionary events underlying transitions from tetrapolar to bipolar and pseudobipolar mating configurations. The phylogenetic tree highlights inferred changes in MAT locus structure, with color-coded branches representing both extant and reconstructed MAT configurations. Dashed lines indicate unresolved phylogenetic relationships among clades A, B, and C. Insets summarize distinct evolutionary stages, including: the ancestral organization with unlinked and compact P/R and HD loci (1); small-scale expansion of the P/R locus in Kwoniella (2); two independent large-scale expansions of the P/R locus in Cryptococcus (5); relocation of P/R and HD loci onto the same chromosome in Kwoniella resulting in either pseudobipolar (3) or fused (4) MAT configurations; and independent HD-P/R fusion events with HD gene loss in Cryptococcus pathogens and Cryptococcus sp. 3 (6). These transitions illustrate the diverse pathways by which chromosomal rearrangements (CRs) have shaped MAT locus architecture in these fungal lineages.
Evolution of fungal mating systems: Study of #Cryptococcus & Kwoniella by @marcoacoelho.bsky.social @marciadavidpalma.bsky.social &co shows that MAT locus fusions & recombination suppression drive diversity of #SexualReproduction in #fungi @plosbiology.org 🧪 plos.io/479579M
