الفهرس 
RNA interference of carboxyesterases causes nymph mortality in the Asian citrus psyllid, Diaphorina citri.Only 14 pages are availabe for public view
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Abstract
Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an important pest of citrus worldwide. The economic losses of D. citri are caused by the direct feeding on the citrus phloem sap and the large accumulation of honeydew. In addition it transmits Candidatus Liberibacter asiaticus (CLas), the causal pathogen of Huanglongbing (HLB), also known as citrus greening disease. HLB is one of the most highly destructive diseases in citrus groves which threatens citrus production across the world. Neonicoinoids, Organophosphates and carbamates are the most commonly used insecticides for D. citri. The random and continuous use of insecticides caused several critical problems such as insect resistance Many detoxification enzymes control D. citri resistance against insecticides such as general esterases (GEST), cytochrome P450 monooxygenases and glutathione S-transferases (GST). Carboxyesterases (CarE; EC 3.1.1.1), a main detoxification enzyme family, are distributed broadly in insects. AChE, one of the most important CarEs enzyme, plays an important role in the development of insecticide resistance This study aims to develop efficient strategies for D. citri control with low environmental impact such as RNA interference. RNAi was proposed by many researchers as an ecofriendly control for D. citri. 96 Summary & conclusion The first study, insecticide-susceptible laboratory Asian citrus psyllid populations were continuously reared in a growth room without exposure to insecticides. For the dsRNA application, the 4th and 5th nymphal instars were collected. In silico analysis of D. citri carboxyesterase were obtained. Synthesizing of the dsRNAs as follow: For dsRNA-EstFE4, a consensus sequence derived from 14 gene sequences of EstFE4. Likewise, for dsRNAAChE, a consensus sequence chosen from three gene sequences of AChE (Table S1) was used to design. The irrelevant dsRNA-gfp (green fluorescent protein) was used as a control. Also, topical feeding application of dsRNAs were applied on nymphs of D. citri using five diluted concentrations of both dsRNAs (dsRNA-EstFE4 and dsRNA-AChE) as follows: 25, 50, 75, 100 and 125 ng/μl. In addition, RNase free water and dsRNA-gfp were used as controls. Nymphs mortality were calculated and Gene Expression analysis was measured. The obtained results could be listed as follows: 1. Gene expression analysis showed that both AChE transcripts increased about 4 fold from 1st, 2nd, and 3rd nymph instars to the 4th and 5th nymph instars However, the expression levels were slightly lower in the adults than the 4th and 5th nymph instars. Similarly, EstFE4 transcripts increased 3.2-fold in 4th and 5th instars compared to 1st-3rd instars, and 2.4-fold for adults. 2. Treatments with dsRNA-AChE and dsRNA-EstFE4 down-regulated 97 Summary & conclusion carboxyesterase genes expression in adult D. citri 3. dsRNA-AChEand dsRNA- EstFE4 treatments increases nymph mortality. On the other study, Laboratory populations of D. citri adults were tested using four insecticides (chlorpyrifos, carbaryl, fenpropathrin and imidacloprid) belongs to different chemistry classes. Lethal concentrations that caused 50% (LC50) mortality to D. citri adults were determined using a leaf-dip bioassay method. Topical feeding of D. citri 4th and 5th instar nymphs with dsRNA-AChE were assessed using five diluted concentrations of dsRNA-AChE were prepared using RNase-free water as follows: 25, 50, 75, 100 and 125 ng/μl. in addition, insecticides application was achieved for D. citri adults emerged from nymphs treated with dsRNA-AChE using LC50 concentration. Treatments of D. citri adults with dsRNA-AChE were applied via Topical feeding. Furthermore, insecticides bioassay for D. citri adults after treated with dsRNA-AChE by the leaf-dip bioassay method was tested and the gene expression analysis for adults treated dsRNA-AChE was measured.