Characterization of a Single Clonal Lineage ofFusarium oxysporumf. sp.albedinisCausing Bayoud Disease of Date Palm in Morocco

Abstract

L rpd 3 66; p : ; Bayoud, the Fusarium wilt of date palm, was first detected in southern Morocco (Draa Valley), after which it spread to most of the Moroccan palm groves. To assess whether the epidemic results from the spread of a single virulent clone, 42 isolates of Fusarium oxysporunz f. sp. albedinis were collected from several cultivars of wilted palms at different locations in Morocco; two isolates were included from Algeria, where the disease also occurs. The isolates were tested for vegetatjWcompatibility group (VCG), restriction fragment length polymorphism .(RFLP), and random amplified polymorphic DNA (RAPD). No polymorphism was observed either in RFLP studies on mitochondrial DNA o;ih RAPD analysis, and all strains belonged to a single VCG (0170). Sequences homologous to the DNA transposable element Fotl were found in the genome of the F: oxysporum f. sp. albedinis strains. Repetitive DNA patterns were produced when EcoRI-digested DNA of the isolates was probed with Fotl; 23 distinct hybridization patterns were established among the 44 isolates. Of these patterns, 4 accounted for more than 50% of the isolates, 1 was found twice, and 18 were represented by a single isolate each. Common hybridization patterns were found in the Moroccan palm groves surveyed; the two Algerian isolates had a pattern that also was found in the Draa Valley. Cluster analysis grouped most of the E oxysporurn f. sp. albedinis strains at a genetic distance of 0.11. Such close genetic relationships between the isolates provides evidence that Moroccan E ogsporum f. sp. albedinis populations may belong to a single clonal lineage that originated in Moroccan palm groves and eventually reached the Algerian oases.

Genetic Diversity of Human Pathogenic Members of the Fusarium oxysporum Complex Inferred from Multilocus DNA Sequence Data and Amplified Fragment Length Polymorphism Analyses: Evidence for the Recent Dispersion of a Geographically Widespread Clonal Lineage and Nosocomial Origin

“…This clonal lineage consisted of only seven highly similar AFLP genotypes, and all of its members shared identical or nearly identical EF-1␣ and IGS rDNA sequences and possessed only MAT1-1 idiomorphs, indicating that they were of clonal origin. To date, molecular epidemiological studies that have identified fungal pathogens with a highly clonal population structure are restricted to a relatively small number of clinically (8,9), zoologically (17), and agriculturally (4, 5, 11) important species, including members of the FOC (13,29). However, most clinically important fungi investigated to date isolates indicated by shading.…”

Variability amongst strains of Fusarium poae assessed by vegetative compatibility and RAPD polymorphism

“…There is evidence that, in asexual fungi, vegetatively compatible strains are more similar in molecular traits than vegetatively incompatible strains of the same species (Appel & Gordon, 1995;Boehm et al, 1994;Gordon & Okamoto, 1992b;Jacobson & Gordon, 1990;Kim et al, 1993;Kistler et al, 1987Kistler et al, , 1991Tantaoui et al, 1996;Toth & Lacy, 1991) at least in the case of highly specialized pathogenic subgroups. RAPD patterns were found to be closely associated with VCGs within Fusarium oxysporum f.sp.…”

Nitrate Non-Utilizing Mutants and Vegetative Compatibility Groups of Fusarium Proliferatum and F. Sacchari Isolated from Rice in the Peninsular Malaysia and Kalimantan, Indonesia

“…This phenomenon occurs when isolates from different VCGs fuse to form heterokaryotic cells but with different degrees of cytoplasmic incompatibility, which then causes the produced heterokaryon to be unstable, and the fused cell of cytoplasm dies (Leslie and Summerell 2006;Deacon 2006). Isolates in the same VCG are more similar in molecular traits and are different from isolates in other VCGs of the same species (Gordon and Okamoto 1992;Tantaoui et al 1996). VC is controled by several gene loci and this may results in the genetic isolation of isolates within a population (Perkins et al 1982;Puhalla and Speith 1983).…”