Genetic structure of Malus sylvestris and potential link with preference/performance by the rosy apple aphid pest Dysaphis plantaginea

Abstract

AbstractThe European crabappleMalus sylvestris, a crop wild relative ofMalus domestica, is a major contributor to the cultivated apple genome and represents a potential source of interesting alleles or genes, particularly pest resistance traits. An original approach was used to explore the trophic interaction betweenM. sylvestrispopulations and its pest, the rosy apple aphid (Dysaphis plantaginea). Using 13 microsatellite markers, population genetic structure and level of crop-to-wild introgressions were inferred betweenM. sylvestrisseedlings from three sites in Europe (Denmark, France, Romania), andM. domesticaseedlings. Genetically characterized plants were also used to analyze aphid feeding behavior and fitness parameters. First, aphids submitted to two genetically closeM. sylvestrispopulations (the Danish and French) exhibited similar behavioral parameters, suggesting similar patterns of resistance in these host plants. Second, the RomanianM. sylvestrispopulation was most closely genetically related toM. domestica. Although the two plant genetic backgrounds were significantly differentiated, they showed comparable levels of sensitivity toD. plantagineainfestation. Third, aphid fitness parameters were not significantly impacted by the host plant’s genetic background. Finally, crop-to-wild introgression seemed to significantly drive resistance toD. plantagineaindependent of host plant population genetic structure, with hybrids being less suitable hosts.