Fusarium oxysporum f. sp. passiflorae isolates display variable virulence in Passiflora edulis Sims seedlings

Genetic variability among Fusarium oxysporum f. sp. passiflorae (FOP) isolates changes their aggressiveness pattern under controlled conditions. This study aimed at assessing the aggressiveness of FOP isolates in Passiflora edulis seedlings through survival analysis as well as anatomic analyses of infected roots. The study followed a completely randomized design with nine FOP isolates used to inoculate 30 P. edulis seedlings. Data were subjected to survival analysis based on Kaplan-Meier curves. The number of chlamydospores in the roots was counted through root clarification and microscopy. The incidence of wilted plants ranged from 20% to 90% of the isolates with an average of 50%. Isolate CMF3115 was the most aggressive with 70% of dead plants up to 70 d.a.i. and only 3% of plants surviving the disease. Although this outcome is possibly not correlated to mortality, this isolate was also responsible for large numbers of chlamydospores in roots. Thus, CMF3115 has the potential to be used for Passiflora germplasm screening under controlled conditions and may contribute to the selection of P. edulis cultivars resistant to FOP.

Automated summary

Genetic variability among Fusarium oxysporum f. sp. passiflorae (FOP) isolates affects their aggressiveness, with isolate CMF3115 being the most aggressive in this study. This isolate also showed high levels of chlamydospores in roots, suggesting potential for screening Passiflora germplasm for resistance to FOP.