Aggressiveness and genetic diversity of Fusarium oxysporum f. sp. cubense from Santa Catarina, southern Brazil

This work aimed to verify the genetic variability of Fusarium oxysporum f. sp. cubense isolates based on aggressiveness and molecular data (ISSR, SSR and sequencing of the TEF-1α gene). A total of 152 isolates collected from banana-producing areas in the north and south regions of the state of Santa Catarina, Brazil, were compared. Isolates were collected from plants belonging to the Pome and Cavendish subgroups. Pathogenicity was confirmed for all isolates, and morphological traits confirmed the identity of the fungus. Greenhouse assays allowed classification of the isolates into three groups according to their aggressiveness. Results from ISSR, SSR and DNA sequencing revealed less variation since the majority of the isolates displayed 100 % similarity. Among the markers, ISSR and SSR were the most polymorphic in terms of differentiating with a larger percentage of dissimilarity. Results from aggressiveness tests indicated a tendency towards a consistent structure according to host or geographical origin of the isolates. No relationship between DNA markers and aggressiveness of isolates could be established.