Genetic diversity of plant pathogen valsa sordida using microsatellite markers

The genetic diversity of Valsa sordida isolates from different geographical regions and hosts was investigated using MP-PCR markers. PCR amplifications were done using eight primers. Of them, only four primers [(ATC)7, (ACTG)4, (CGA)5, and (AAC)8] produced polymorphic bands. At least 88.5% polymorphism was revealed by four primers and the maximum polymorphism (97%) was generated by (ACTG)4 primer and three diagnosable groups (1, 2 and 3) were resolved in the resulting dendrogram constructed by the UPGMA algorithm. The results showed high polymorphism among the isolates and confirmed the merit and accuracy of the MP-PCR markers for studying the genetic variability of V. sordida isolates at the intra-species level. We have not found any correlations between observed genetic diversity and the geographical region or host plant of the isolates, unless in limited cases. The abundant formation of the sexual state of the fungus in the infected parts of trees, as well as possible asexual recombination during asexual reproduction, are suggested as influencing factors of high genetic variability among the individuals.