Genetic transformation patterns along a longitude gradient in Ukrainian populations of Schizophyllum commune fungus

The research of fungal biodiversity is important under global climate change and increasing anthropogenic pressure on ecosystems. The most studies focusing on fungal biogeography oriented on species richness. There is a short supply researches on how genetic diversity shifts along a longitudinal gradient within one species. Model fungi with well-characterized genomes and simple cultivation requirements allow detailed research of evolutionary and ecological processes. The aim was to study the genetic profile transformation of the Schizophyllum commune populations by DNA microsatellite loci along a longitude gradient in Ukraine to establish genetic migration relationships and historical features of population development. Our findings reveal that S. commune populations from eastern to western Ukraine, show local genetic differentiation. The separation of populations into three clusters (Don + KrR, Vin + Cher, and I-F) reflects historically independent developmental trajectories. The Mantel test revealed weak but significant isolation by distance (r = 0.1048, p = 0.0016). However, the negative global correlation (Pearson r ≈ -0.56) suggests pure isolation by distance is not the dominant process shaping these populations. The biological significance of the spatial populations pattern suggests that landscape zonation and various ecological barriers restrict local gene flow, whereas long-distance spore dispersal prevents complete isolation. We identified a complex, asymmetric structural network of populations with a core (Don ↔ KrR), pronounced donor populations (Cher and I-F), and a partial peripheral element (Vin). In the absence of pronounced geographic barriers, S. commune populations can maintain local genetic differentiation. Connection density profile fluctuations within populations are shaped by various processes that actively contribute to population disintegration or consolidation and represent signatures of their evolutionary pathways.