title: Assessment of the Dominance Level of the R81T Target Resistance to Two Neonicotinoid Insecticides in Myzus persicae (Hemiptera: Aphididae).
abstract: Myzus persicae (Sulzer, 1776), a major crop pest worldwide, displays insecticide resistance to most molecules. The R81T substitution on the β1 subunit of nicotinic receptors of acetylcholine (nAChR) confers target site resistance to neonicotinoids and is widespread in aphid populations colonizing peach tree orchards in Southern Europe. But the impact of this resistance in the field, as well as ways to optimize its management, depends largely on the dominance level of the R81T mutation. In this study, we measured by in vitro assays the response of R81T mutation to two neonicotinoids (imidacloprid and thiacloprid) in 23 M. persicae clones with different resistance genotypes in order to assess the dominance status of this allele. In this study, all homozygous clones for the R81T mutation (genotype 81(TT)) showed a much higher level of resistance to both active substances than other clones. The heterozygous clones 81(RT) displayed a slightly higher level of resistance than wild homozygous, though resistance phenotypes against both neonicotinoids in these two genotypes were overlapping. A great variation of resistance level was found within these two latter clones' categories. The dominance level of insecticide resistance (DLC) strongly suggested that the mutant allele 81T is semirecessive (the wild 81R allele being rather dominant) for both insecticide molecules under test. Mean DLC values were 0.316 for imidacloprid and 0.351 for thiacloprid. Cross-resistance was shown between imidacloprid and thiacloprid. This partial recessivity is valuable information to broaden the knowledge on neonicotinoid resistance, a prerequisite for devising adapted management strategies against insecticide-resistant populations of M. persicae.
authors: ANSES - Laboratoire de Lyon, Unité Résistance aux Produits Phytosanitaires, 31, avenue Tony Garnier, 69364 Lyon cedex 07, France (claire.mottet@anses.fr; severine.fontaine@anses.fr; laetitia.caddoux@anses.fr; christine.brazier@anses.fr; annie.micoud@anses.fr) claire.mottet@anses.fr.
authors: Claire
authors: C
authors: Mottet
authors: ANSES - Laboratoire de Lyon, Unité Résistance aux Produits Phytosanitaires, 31, avenue Tony Garnier, 69364 Lyon cedex 07, France (claire.mottet@anses.fr; severine.fontaine@anses.fr; laetitia.caddoux@anses.fr; christine.brazier@anses.fr; annie.micoud@anses.fr).
authors: Séverine
authors: S
authors: Fontaine
authors: ANSES - Laboratoire de Lyon, Unité Résistance aux Produits Phytosanitaires, 31, avenue Tony Garnier, 69364 Lyon cedex 07, France (claire.mottet@anses.fr; severine.fontaine@anses.fr; laetitia.caddoux@anses.fr; christine.brazier@anses.fr; annie.micoud@anses.fr).
authors: Laëtitia
authors: L
authors: Caddoux
authors: ANSES - Laboratoire de Lyon, Unité Résistance aux Produits Phytosanitaires, 31, avenue Tony Garnier, 69364 Lyon cedex 07, France (claire.mottet@anses.fr; severine.fontaine@anses.fr; laetitia.caddoux@anses.fr; christine.brazier@anses.fr; annie.micoud@anses.fr).
authors: Christine
authors: C
authors: Brazier
authors: INRA UMR Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Domaine de la Motte, 35653 LE RHEU, France (frederique.maheo@rennes.inra.fr; jean-christophe.simon@rennes.inra.fr).
authors: Frédérique
authors: F
authors: Mahéo
authors: INRA UMR Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Domaine de la Motte, 35653 LE RHEU, France (frederique.maheo@rennes.inra.fr; jean-christophe.simon@rennes.inra.fr).
authors: Jean-Christophe
authors: JC
authors: Simon
authors: ANSES - Laboratoire de Lyon, Unité Résistance aux Produits Phytosanitaires, 31, avenue Tony Garnier, 69364 Lyon cedex 07, France (claire.mottet@anses.fr; severine.fontaine@anses.fr; laetitia.caddoux@anses.fr; christine.brazier@anses.fr; annie.micoud@anses.fr).
authors: Annie
authors: A
authors: Micoud
authors: UMR 5175 CEFE Centre d'Ecologie Fonctionnelle et évolutive, Equipe Interactions Biotiques, 1919, Route de Mende, 34293 Montpellier cedex 5, France (lise.roy@univ-montp3.fr).
authors: Lise
authors: L
authors: Roy
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects* / Q000235:genetics*; D005602:France; D005838:Genotype; D007093:Imidazoles / Q000494:pharmacology; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D009154:Mutation; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D013843:Thiazines / Q000494:pharmacology
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011725:Pyridines; D013843:Thiazines; C082359:imidacloprid; C417209:thiacloprid
keywords: Myzus persicae; R81T mutation; dominance level; neonicotinoid; resistance