Population differentiation and genetic diversity of Trichophyton rubrum as revealed by highly discriminatory microsatellites

Little is known regarding the population information of Trichophyton rubrum due to a lack of strains with clear sampling information and molecular markers with high discriminatory power. In the present study, we developed a set of microsatellite markers that have a cumulative discriminatory power was 0.993. Using these microsatellites loci, 243 strains T. rubrum that had clear sampling information were analysed. Three genetic diversity indices (Shannon’s Information Index, Nei’s unbiased gene diversity and allelic richness) were shown to be related to the human population size of the sampling city rather than mean annual temperature or humidity. Population structure analyses revealed that T. rubrum can be separated into two clusters. AMOVA results indicated that genetic variation was more significant between these two clusters than among geographical populations. Our work is the first to reveal population information of T. rubrum using highly discriminatory molecular markers, and suggest that T. rubrum populations in cities with larger population size might have better adaptability due to higher genetic diversity under selective pressures (such as antifungal agents).