Overexpression of Two Odorant Binding Proteins Confers\nChlorpyrifos Resistance in the Green Peach Aphid Myzus\npersicae

The green peach aphid, Myzus persicae, is a worldwide agricultural pest.\nChlorpyrifos has been widely\nused to control M. persicae for decades,\nthus leading to a high resistance to chlorpyrifos. Recent studies\nhave found that insect odorant binding proteins (OBPs) play essential\nroles in insecticide resistance. However, the potential resistance\nmechanism underlying the cross-link between aphid OBPs and chlorpyrifos\nremains unclear. In this study, two OBPs (MperOBP3 and MperOBP7) were\nfound overexpressed in M. persicae chlorpyrifos-resistant\nstrains (CRR) compared to chlorpyrifos-sensitive strains (CSS); furthermore,\nchlorpyrifos can significantly induce the expression of both OBPs.\nAn <i>in vitro</i> binding assay indicated that both OBPs\nstrongly bind with chlorpyrifos; an <i>in vivo</i> RNAi\nand toxicity bioassay confirmed silencing either of the two OBPs can\nincrease the susceptibility of aphids to chlorpyrifos, suggesting\nthat overexpression of MperOBP3 and MperOBP7 contributes to the development\nof resistance of M. persicae to chlorpyrifos.\nOur findings provide novel insights into insect OBPs-mediated resistance\nmechanisms.