ABSTRACT
Tobacco has faced rising problems due to diseases in Southern Brazil in recent years. Among the main diseases, the white mold caused by Sclerotinia sclerotiorum has significant impact. Information about the genetic profile of the pathogen, its level of aggressiveness, as well as the resistance of tobacco genotypes is still scarce. Therefore, in this study, we evaluated the genetic profile of 33 isolates of S. sclerotiorum from different places in the states of Rio Grande do Sul, Santa Catarina, Paraná and São Paulo, and the aggressiveness of 10 isolates in five tobacco genotypes. Aggressiveness was tested by inoculating fungus celium on stalks of tobacco plants in a greenhouse. The genetic profile of the 33 isolates was assessed by microsatellite technique. Fungus isolates and tobacco genotypes showed different profiles of aggressiveness and resistance, respectively. A total of 114 alleles were detected with an average of 11 alleles per locus and no clones were observed. Some markers showed null allele in some genotypes, particularly marker 99, which was null in 14 isolates. Unique alleles were found for 61% of the isolates. The analysis of polymorphism information content (PIC) was highly informative for all markers. Isolates from different States of Southern Brazil did not form distinct groups, indicating that the origin site was not a determining factor of variability. The Cluster analysis indicated that smaller populations from Paraná and Rio Grande do Sul do not differ genetically from the larger population from Santa Catarina.
Keywords
white mold; molecular characterization; microsatellite; SSR
