Genetic discontinuities and disequilibria in recently established populations of the plant pathogenic fungus Mycosphaerella fijiensis

Halkett Fabien, Coste David, Rivas Gonzalo Galilaeo, Zapater Marie-Françoise, Abadie Catherine, Carlier Jean. 2010. Genetic discontinuities and disequilibria in recently established populations of the plant pathogenic fungus Mycosphaerella fijiensis. Molecular Ecology, 19 (18) : 3909-3923.

https://doi.org/10.1111/j.1365-294X.2010.04774.x

Article de revue ; Article de revue à facteur d'impact

Version publiée - Anglais
Accès réservé aux personnels Cirad
Utilisation soumise à autorisation de l'auteur ou du Cirad.
document_556427.pdf
Télécharger (501kB)

Quartile : Q1, Sujet : ECOLOGY / Quartile : Q1, Sujet : EVOLUTIONARY BIOLOGY / Quartile : Q1, Sujet : BIOCHEMISTRY & MOLECULAR BIOLOGY

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Psychologie-éthologie-ergonomie

Résumé : Dispersal processes of fungal plant pathogens can be inferred from analysis of spatial genetic structures resulting from recent range expansion. The relative importance of longdistance dispersal (LDD) events vs. gradual dispersal in shaping population structures depends on the geographical scale considered. The fungus Mycosphaerella fijiensis, pathogenic on banana, is an example of a recent worldwide epidemic. Founder effects in this species were detected at both global and continental scale, suggesting stochastic spread of the disease through LDD events. In this study, we analysed the structure of M. fijiensis populations in two recently (_1979-1980) colonized areas in Costa Rica and Cameroon. Isolates collected in 10-15 sites distributed along a _250- to 300- km-long transect in each country were analysed using 19 microsatellite markers. We detected lowto- moderate genetic differentiation among populations in both countries and isolation by distance in Cameroon. Combined with historical data, these observations suggest continuous range expansion at the scale of banana-production area through gradual dispersal of spores. However, both countries displayed specific additional signatures of colonization: a sharp discontinuity in gene frequencies was observed along the Cameroon transect, while the Costa Rican populations seemed not yet to have reached genetic equilibrium. These differences in the genetic characteristics of M. fijiensis populations in two recently colonized areas are discussed in the light of historical data on disease spread and ecological data on landscape features.

Mots-clés Agrovoc : Mycosphaerella fijiensis, Musa, maladie des raies noires

Mots-clés géographiques Agrovoc : Costa Rica, Cameroun

Classification Agris : H20 - Maladies des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations