title: Status of Resistance of Bemisia tabaci (Hemiptera: Aleyrodidae) to Neonicotinoids in Iran and Detoxification by Cytochrome P450-Dependent Monooxygenases.
abstract: Nine Bemisia tabaci (Gennadius) populations were collected from different regions of Iran. In all nine populations, only one biotype (B biotype) was detected. Susceptibilities of these populations to imidacloprid and acetamiprid were assayed. The lethal concentration 50 values (LC50) for different populations showed a significant discrepancy in the susceptibility of B. tabaci to imidacloprid (3.76 to 772.06 mg l-1) and acetamiprid (4.96 to 865 mg l-1). The resistance ratio of the populations ranged from 9.72 to 205.20 for imidacloprid and 6.38 to 174.57 for acetamiprid. The synergistic effects of piperonylbutoxide (PBO) and S,S,S-tributylphosphorotrithioate (DEF) were evaluated for the susceptible (RF) and resistant (JR) populations for the determination of the involvement of cytochrome P450-dependent monooxygenase and carboxylesterase, respectively, in their resistance mechanisms. The results showed that PBO overcame the resistance of the JR population to both imidacloprid and acetamiprid, with synergistic ratios of 72.7 and 106.9, respectively. Carboxylesterase, glutathione S-transferase and cytochrome P450-dependent monooxygenase were studied biochemically, for the purpose of measuring the activity of the metabolizing enzymes in order to determine which enzymes are directly involved in neonicotinoid resistance. There was an increase in the activity of cytochrome P450-dependent monooxygenase up to 17-fold in the resistant JR population (RR = 205.20). The most plausible activity of cytochrome P450-dependent monooxygenase correlated with the resistances of imidacloprid and acetamiprid, and this suggests that cytochrome P450-dependent monooxygenase is the only enzyme system responsible for neonicotinoid resistance in the nine populations of B. tabaci.
authors: Dept of Plant Protection, Univ College of Agriculture and Natural Resources, Univ of Tehran, Tehran, Iran.
authors: M
authors: M
authors: Basij
authors: Dept of Plant Protection, Univ College of Agriculture and Natural Resources, Univ of Tehran, Tehran, Iran. khtalebi@ut.ac.ir.
authors: K
authors: K
authors: Talebi
authors: Dept of Plant Protections, College of Agricultural Sciences, Univ of Guilan, Rasht, Iran.
authors: M
authors: M
authors: Ghadamyari
authors: Dept of Plant Protection, Univ College of Agriculture and Natural Resources, Univ of Tehran, Tehran, Iran.
authors: V
authors: V
authors: Hosseininaveh
authors: Dept of Biotechnology, Univ of Tehran, Tehran, Iran.
authors: S A
authors: SA
authors: Salami
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D006430:Hemiptera / Q000502:physiology*; D007305:Insecticide Resistance; D007306:Insecticides; D007492:Iran
chemical_list: D007306:Insecticides; D003577:Cytochrome P-450 Enzyme System
keywords: Insecticide resistance; acetamiprid; enzyme inhibitors; imidacloprid; resistance mechanism