Diversity, Pathogenicity, and Fumonisin Biosynthetic Gene Profiles of Fusarium fujikuroi Species Complex Isolates Associated with Banana Crown Rot in Northeastern Brazil

Crown rot is an important postharvest disease of banana and is frequently associated with species of the Fusarium fujikuroi species complex (FFSC). This study investigated the diversity, pathogenicity, and fumonisin biosynthetic gene profiles of FFSC isolates associated with banana crown rot in the Cariri region, Ceará, northeastern Brazil. Among the 151 Fusarium isolates recovered, 64 were assigned to the FFSC based on tef1-α and RPB2 sequence analyses. Five species were identified: F. annulatum, F. joanfreemaniae, F. musae, F. pseudocircinatum, and F. verticillioides. Thirty-five isolates caused lesions on wounded banana fruits, with marked variation in aggressiveness. Fusarium musae was the most frequent and generally the most aggressive species, whereas all F. verticillioides isolates were non-pathogenic under the conditions tested. PCR screening detected FUM1 and/or FUM8 markers in 28 isolates, including pathogenic and non-pathogenic isolates, while no amplicons were detected in F. joanfreemaniae. These findings expand current knowledge of FFSC diversity associated with banana crown rot in Brazil and reveal substantial inter- and intraspecific variation in pathogenicity, aggressiveness, and fumonisin biosynthetic gene profiles, highlighting the need to assess pathogenicity and potential toxigenic risk independently.