Identification of Novel Potential Causal Agents of Fusarium Wilt of Musa sp. AAB in Southern Mexico

A major threat for bananas and plantains production is the Panama Disease or Fusarium Wilt caused by Fusarium oxysporum f. sp. cubense. In order to characterize the causal agents of Fusarium wilt in Mexico, a sampling was performed in symptomatic plantains growing in fields of Oaxaca, a coastal southern state of Mexico. A phylogenetic analysis based on the sequences of TEF 1-α and IGS revealed that three isolates belonged to the Fusarium oxysporum species complex, while two other isolates were identified as members of the Fusarium fujikuroi species complex. Furthermore, isolates from the same complex shared the same ITS2 sequence. Inoculation using spores of each isolate on the roots of Musa sp. AAB cv. Manzano produced wilting symptoms of varying severity, suggesting that the Fusarium wilt might not be caused only by Fusarium oxysporum f. sp. cubense. PCR-based detection of Secreted in Xylem (SIX) genes showed that each Fusarium isolate harbored a unique combination of genes typically found in banana pathogens, which might cause the disease.