Genetic differentiation in the French population of Erysiphe cichoracearum, a causal agent of powdery mildew of cucurbits

Bardin Marc, Carlier Jean, Nicot P.C.. 1999. Genetic differentiation in the French population of Erysiphe cichoracearum, a causal agent of powdery mildew of cucurbits. Plant Pathology, 48 : 531-540.

Autre titre : Différentiation génétique dans la population française de Erysiphe cichoracearum, agent causal du mildiou chez les curcubitacées

Résumé : The relative incidence of Erysiphe cichoracearuin and Sphaerotheca fuliginea, both agents of powdery mildew of cucurbits, was determined from 275 samples of mildewed leaves of cucurbits collected in 1994 from five regions of France. E. cichoracearuin was identified in 9 to 39% of the milde~,ved leaf samples from four of the regions but was not detected in samples from the Mediterranean island of Corsica. The genetic structure of the French population of E. cichoracearuni was examined using RFLPs of the ribosomal internal transcribed spacers amplified by PCR, random amplified polymorphic DNA (RAPD) markers, pathogeniciry and mating-type tests. Forty-one isolates, including one from England, were analysed. Cluster analysis from 147 RAPD fragments using 16 primers revealed the existence of three distinct genetic lineages corresponding to three rDNA haplotypes (designated groups A, B and C). Bootstrap, genetic diversity, gametic disequilibrium and private allele analyses supported this differentiation. The genetic differentiation observed in the French population was not related to the geographical origin of the isolates. Group A isolates may be more specialized on melon as, with one exception, they were of race 1 (growth on four of the five melon cultivars tested) in comparison with group B and C isolates, which were of race 0 (growth on IranH only). Thus, the genetic differentiation observed may indicate a host-specialized subdivision within the French population of E. cichoracearum from cucurbits. Gametic disequilibrium analysis among RAPD loci and biological observations suggest that the sexual stage is of minor importance for epidemics of E. cichoracearuni on cucurbits.

Mots-clés Agrovoc : Erysiphe cichoracearum, Sphaerotheca fuliginea, pouvoir pathogène, structure de la population, technique analytique, RAPD, Cucurbitaceae

Mots-clés complémentaires : Structure génétique

Classification Agris : H20 - Maladies des plantes

Auteurs et affiliations

• Bardin Marc
• Carlier Jean, CIRAD-AMIS-PROTECTION DES CULTURES (FRA) ORCID: 0000-0002-6967-1852
• Nicot P.C.

Source : Cirad - Agritrop (https://agritrop.cirad.fr/391961/)

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