Inbreeding levels of two Ustilago maydis populations.

摘要

Little is known about the population mating behaviour of the smut fungus Ustilago maydis [U. zeae]. To determine the amount of inbreeding that occurs in local U. maydis populations, two maize fields were sampled, one in North America (NA) at Le Sueur, Minnesota, and one in South America (SA) at Tarariras, Uruguay. These fields were chosen because of their geographic isolation and host management differences. Inbreeding coefficients (Fis) were calculated using data derived from amplified fragment length polymorphism markers. Mean Fis values estimated for both the NA (-0.08), and the SA (-0.02) populations statistically are not different from zero. The results of this study demonstrate that the U. maydis population structure in both fields results predominately from out-crossing and suggests that teliospores infrequently act as single infection units. The genetic differentiation between populations was high (Fst=0.25).