Use of microsatellite markers in the characterization of genetic diversity of Venturia inaequalis causing apple scab in the northeastern U.S

The efficiency of microsatellite markers in the characterization of population structure of Venturia inaequalis causing apple scab in the northeastern U.S. was tested. In an initial screening forty PCR primers amplifying twenty microsatellite loci, that were previously developed from European isolates of V. inaequalis, were used to characterize the genetic diversity of isolates from various geographical regions and obtained from different hosts (cultivated apples and ornamental crabapples from various Malus spp.) in the U.S. Microsatellite alleles were detected using fluorescence-labeled primers and capillary electrophoresis. Data was analyzed using the Genescan analysis software, and allele frequencies were calculated as co-dominant markers using POPGENE software. All primers successfully generated amplicons. The number of alleles for the various microsatellite markers ranged from one to thirteen among the isolates tested. Allelic variation was identified among the isolates of V. inaequalis regardless of host or geography of origin. This study indicates that microsatellite markers could serve as a useful tool in the characterization of genetic diversity of V. inaequalis isolates.