title: When virulence originates from nonagricultural hosts: evolutionary and epidemiological consequences of introgressions following secondary contacts in Venturia inaequalis.
abstract: In pathogens, introgressions through secondary contacts between divergent populations from agricultural and nonagricultural disease reservoirs are expected to have crucial evolutionary and epidemiological implications. Despite the importance of this question for disease management, experimental demonstrations of these implications remain scarce. Recently, we identified a virulent population of the apple scab pathogen Venturia inaequalis that migrated from nonagricultural hosts to European domestic apple orchards. Here, we investigated the occurrence of gene flow between agricultural and nonagricultural populations sampled in two orchards, and thereafter its consequences on the pathogenicity of hybrids. Population genetic structure and demographic inferences based on the genotypes of 104 strains revealed a high amount of gene flow between the two populations in one orchard. In this site, mating between populations was made possible by the presence of a common host. Our results revealed an invasion of the virulent trait in the agricultural population; a main direction of introgression in hybrids from the agricultural to nonagricultural genetic backgrounds; and a population of hybrids with transgressive traits. We demonstrate a secondary contact with gene flow between divergent populations of pathogens. Our findings highlight evolutionary and epidemiological changes in pathogens and have concrete implications for sustainable disease management.
authors: INRA, ACO, Université d'Angers - UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), SFR4207 QUASAV, PRES LUNAM, Beaucouze, France.
authors: Thibault
authors: T
authors: Leroy
authors: INRA, ACO, Université d'Angers - UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), SFR4207 QUASAV, PRES LUNAM, Beaucouze, France.
authors: Valérie
authors: V
authors: Caffier
authors: INRA, ACO, Université d'Angers - UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), SFR4207 QUASAV, PRES LUNAM, Beaucouze, France.
authors: Jean-Marc
authors: JM
authors: Celton
authors: INRA, ACO, Université d'Angers - UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), SFR4207 QUASAV, PRES LUNAM, Beaucouze, France.
authors: Nicolas
authors: N
authors: Anger
authors: INRA, ACO, Université d'Angers - UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), SFR4207 QUASAV, PRES LUNAM, Beaucouze, France.
authors: Charles-Eric
authors: CE
authors: Durel
authors: INRA, ACO, Université d'Angers - UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), SFR4207 QUASAV, PRES LUNAM, Beaucouze, France.
authors: Christophe
authors: C
authors: Lemaire
authors: INRA, ACO, Université d'Angers - UMR1345 Institut de Recherche en Horticulture et Semences (IRHS), SFR4207 QUASAV, PRES LUNAM, Beaucouze, France.
authors: Bruno
authors: B
authors: Le Cam
mesh_terms: D000383:Agriculture; D001203:Ascomycota / Q000235:genetics / Q000472:pathogenicity*; D005075:Biological Evolution; D004197:Disease Reservoirs / Q000382:microbiology; D051456:Gene Flow; D056426:Genetic Loci; D005828:Genetics, Population; D005838:Genotype; D006824:Hybridization, Genetic; D027845:Malus / Q000382:microbiology*; D008962:Models, Theoretical; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology* / Q000517:prevention & control; D014774:Virulence
keywords: aggressiveness; apple; apple scab (Venturia inaequalis); gene flow; hybrid swarm; hybridization; resistance management; wild habitat