Genetic studies on Fusarium oxysporum f. sp. albedinis
Fusarium oxysporum f. sp. albedinis (EPPO A2 quarantine pest) can be differentiated from non pathogenic F. oxysporum isolated from date palm roots or soil (see EPPO RS 95/100). This suggests that little genetic variability may exist within F. oxysporum f.sp. albedinis. Genetic studies have been conducted to test the hypothesis of the unique origin of F. oxysporum f. sp. albedinis isolates, as a result of the invasion of the Moroccan oases by a single virulent clone. 42 isolates were collected from several cultivars and different locations in Morocco, and 2 isolates from Algeria were also included. All isolates were tested for vegetative compatibility and genetic variability by RFLP (restriction fragment length polymorphism) and RAPD (random amplified polymorphic DNA). Both nuclear and mitochondrial genome were examined. Results showed that all isolates belonged to the same vegetative compatibility group and no polymorphism was observed either with RAPD or RFLP. Cluster analysis showed that most of the F. oxysporum f. sp. albedinis isolates were grouped at a small genetic distance. The authors concluded that this genetic homogeneity supports the hypothesis that Moroccan populations of F. oxysporum f. sp. albedinis may belong to a single clonal lineage that originated in Moroccan palm groves which then reached the Algerian oases.
Sources
Tantaoui, A.; Ouiten, M.; Geiger, J.P.; Fernandez, D. (1996) Characterization of a single clonal lineage of Fusarium oxysporum f.sp. albedinis causing Bayoud disease of date palm in Morocco.
Phytopathology, 86(7), 787-792.