title: Wild Solanum resistance to aphids: antixenosis or antibiosis?
abstract: The type (antixenosis or antibiosis) of resistance against the aphids Myzus persicae (Sulzer) and Macrosiphum euphorbiae (Thomas) was characterized for the wild tuber-bearing potatoes, Solanum chomatophilum Bitter and Solanum stoloniferum Schltdl. & Bouché through behavioral (olfactometry and electrical penetration graph) and physiological studies. In dual-choice assays, only S. stoloniferum exerted attraction to M. euphorbiae. This ruled out the possibility that plant volatiles of S. chomatophilum and S. stoloniferum may contribute to the high resistance expressed. In electrical penetration graph experiments, aphids feeding on S. stoloniferum showed increased salivation phases, whereas phloem ingestion was drastically reduced for both aphid species. Because reaching phloem elements was not delayed in both species, the resistance mechanism was phloem-located. The antixenosis exhibited by S. stoloniferum was similar on young and mature leaves. S. chomatophilum also showed phloem-located antixenosis against M. persicae. In contrast, M. euphorbiae had no difficulty to reach S. chomatophilum phloem tissues and to ingest sap. S. chomatophilum resistance against M. euphorbiae was antibiosis and only expressed in mature leaves, where a complete nymphal mortality was observed.
authors.affiliation: Biologie des Plantes et Contrôle des Insectes Ravageurs (UPRES EA 3900), Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Le Roux
authors.forename: Sébastien
authors.initials: S
authors.lastname: Dugravot
authors.forename: Erick
authors.initials: E
authors.lastname: Campan
authors.forename: Françoise
authors.initials: F
authors.lastname: Dubois
authors.forename: Charles
authors.initials: C
authors.lastname: Vincent
authors.forename: Philippe
authors.initials: P
authors.lastname: Giordanengo
mesh_terms: D000818:Animals; D001042:Aphids / Q000502:physiology*; D006790:Host-Parasite Interactions; D009758:Nymph; D010935:Plant Diseases / Q000276:immunology; D018515:Plant Leaves / Q000469:parasitology; D032322:Solanum / Q000469:parasitology*; D013997:Time Factors