title: RNA interference of carboxyesterases causes nymph mortality in the Asian citrus psyllid, Diaphorina citri.
abstract: Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an important pest of citrus. In addition, D. citri is the vector of Huanglongbing, a destructive disease in citrus, also known as citrus greening disease caused by Candidatus Liberibacter asiaticus. Huanglongbing causes huge losses for citrus industries. Insecticide application for D. citri is the major strategy to prevent disease spread. The heavy use of insecticides causes development of insecticide resistance. We used RNA interference (RNAi) to silence genes implicated in pesticide resistance in order to increase the susceptibility. The activity of dsRNA to reduce the expression of carboxyesterases including esterases FE4 (EstFE4) and acetylcholinesterases (AChe) in D. citri was investigated. The dsRNA was applied topically to the fourth and fifth instars of nymphs. We targeted several EstFE4 and AChe genes using dsRNA against a consensus sequence for each of them. Five concentrations (25, 50, 75, 100, 125 ng/μl) from both dsRNAs were used. The treatments with the dsRNA caused concentration dependent nymph mortality. The highest gene expression levels of both AChe and EstFE4 were found in the fourth and fifth nymphal instars. Gene expression analysis showed that AChe genes were downregulated in emerged adults from dsRNA-AChe-treated nymphs compared to controls. However, EstFE4 genes were not affected. In the same manner, treatment with dsRNA-EstFE4 reduced expression level of EstFE4 genes in emerged adults from treated nymphs, but did not affect the expression of AChe genes. In the era of environmentally friendly control strategies, RNAi is a new promising venue to reduce pesticide applications.
authors.affiliation: Department of Plant Pathology, IFAS, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA.|Department of Plant Protection, Faculty of Agriculture, Tanta University, Tanta, Egypt.
authors.forename: Abdelaziz
authors.initials: A
authors.lastname: Kishk
authors.affiliation: Department of Plant Protection, Faculty of Agriculture, Tanta University, Tanta, Egypt.
authors.forename: Helmy A I
authors.initials: HA
authors.lastname: Anber
authors.affiliation: Department of Plant Protection, Faculty of Agriculture, Tanta University, Tanta, Egypt.
authors.forename: Tsamoh K
authors.initials: TK
authors.lastname: AbdEl-Raof
authors.affiliation: Department of Plant Protection, Faculty of Agriculture, Tanta University, Tanta, Egypt.
authors.forename: AbdEl-Hakeem D
authors.initials: AD
authors.lastname: El-Sherbeni
authors.affiliation: Department of Plant Protection, Faculty of Agriculture, Tanta University, Tanta, Egypt.
authors.forename: Sobhy
authors.initials: S
authors.lastname: Hamed
authors.affiliation: Department of Plant Pathology, IFAS, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA.
authors.forename: Siddarame
authors.initials: S
authors.lastname: Gowda
authors.affiliation: Department of Plant Pathology, IFAS, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA.
authors.forename: Nabil
authors.initials: N
authors.lastname: Killiny
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D043182:Carboxylesterase / Q000037:antagonists & inhibitors* / Q000235:genetics; D006430:Hemiptera / Q000201:enzymology* / Q000235:genetics; D019476:Insect Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D008969:Molecular Sequence Data; D009758:Nymph; D010572:Pest Control, Biological; D034622:RNA Interference
chemical_list: D019476:Insect Proteins; D043182:Carboxylesterase
keywords: Diaphornia citri; RNA interference; acetylcholinesterases; carboxyesterases; insecticides resistance