title: Gene expression during imidacloprid-induced hormesis in green peach aphid.
abstract: Imidacloprid-induced hormesis in the form of stimulated reproduction has previously been reported in green peach aphid, Myzus persicae. Changes in gene expression accompanying this hormetic response have not been previously investigated. In this study, expression of stress response (Hsp60), dispersal (OSD, TOL and ANT), and developmental (FPPS I) genes were examined for two generations during imidacloprid-induced reproductive stimulation in M. persicae. Global DNA methylation was also measured to test the hypothesis that changes in gene expression are heritable. At hormetic concentrations, down-regulation of Hsp60 was followed by up-regulation of this gene in the subsequent generation. Likewise, expression of dispersal-related genes and FPPS I varied with concentration, life stage, and generation. These results indicate that reproductive hormesis in M. persicae is accompanied by a complex transgenerational pattern of up- and down-regulation of genes that likely reflects trade-offs in gene expression and related physiological processes during the phenotypic dose-response. Moreover, DNA methylation in second generation M. persicae occurred at higher doses than in first-generation aphids, suggesting that heritable adaptability to low doses of the stressor might have occurred.
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, CANADA; ; School of Environmental Sciences, Ontario Agricultural College, University of Guelph, Guelph, Ontario, CANADA.
authors.forename: Murali-Mohan
authors.initials: MM
authors.lastname: Ayyanath
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, CANADA;
authors.forename: G Christopher
authors.initials: GC
authors.lastname: Cutler
authors.affiliation: School of Environmental Sciences, Ontario Agricultural College, University of Guelph, Guelph, Ontario, CANADA.
authors.forename: Cynthia D
authors.initials: CD
authors.lastname: Scott-Dupree
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, CANADA;
authors.forename: Balakrishnan
authors.initials: B
authors.lastname: Prithiviraj
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, CANADA;
authors.forename: Saveetha
authors.initials: S
authors.lastname: Kandasamy
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, CANADA;
authors.forename: Kalyani
authors.initials: K
authors.lastname: Prithiviraj
keywords: Hormesis; Myzus persicae; fecundity; gene expression; global DNA methylation