title: Oxidative stress induced by chlorine dioxide as an insecticidal factor to the Indian meal moth, Plodia interpunctella.
abstract: A novel fumigant, chlorine dioxide (ClO2) is a commercial bleaching and disinfection agent. Recent study indicates its insecticidal activity. However, its mode of action to kill insects is yet to be understood. This study set up a hypothesis that an oxidative stress induced by ClO2 is a main factor to kill insects. The Indian meal moth, Plodia interpunctella, is a lepidopteran insect pest infesting various stored grains. Larvae of P. interpunctella were highly susceptible to ClO2 gas, which exhibited an acute toxicity. Physiological damages by ClO2 were observed in hemocytes. At high doses, the larvae of P. interpunctella suffered significant reduction of total hemocytes. At low doses, ClO2 impaired hemocyte behaviors. The cytotoxicity of ClO2 was further analyzed using two insect cell lines, where Sf9 cells were more susceptible to ClO2 than High Five cells. The cells treated with ClO2 produced reactive oxygen species (ROS). The produced ROS amounts increased with an increase of the treated ClO2 amount. However, the addition of an antioxidant, vitamin E, significantly attenuated the cytotoxicity of ClO2 in a dose-dependent manner. To support the oxidative stress induced by ClO2, two antioxidant genes (superoxide dismutase (SOD) and thioredoxin-peroxidase (Tpx)) were identified from P. interpunctella EST library using ortholog sequences of Bombyx mori. Both SOD and Tpx were expressed in larvae of P. interpunctella especially under oxidative stress induced by bacterial challenge. Exposure to ClO2 gas significantly induced the gene expression of both SOD and Tpx. RNA interference of SOD or Tpx using specific double stranded RNAs significantly enhanced the lethality of P. interpunctella to ClO2 gas treatment as well as to the bacterial challenge. These results suggest that ClO2 induces the production of insecticidal ROS, which results in a fatal oxidative stress in P. interpunctella.
authors.affiliation: Department of Bioresource Sciences, Andong National University, Andong 760-749, Republic of Korea.
authors.forename: Sunil
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Bioresource Sciences, Andong National University, Andong 760-749, Republic of Korea.
authors.forename: Jiyeong
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Bioresource Sciences, Andong National University, Andong 760-749, Republic of Korea.
authors.forename: Eunseong
authors.initials: E
authors.lastname: Kim
authors.affiliation: Institute of Life Science and Natural Resources, Korea University, Seoul 136-702, Republic of Korea.
authors.forename: Jahyun
authors.initials: J
authors.lastname: Na
authors.affiliation: Institute of Life Science and Natural Resources, Korea University, Seoul 136-702, Republic of Korea.
authors.forename: Yong Shik
authors.initials: YS
authors.lastname: Chun
authors.affiliation: Department of Life Science and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Hyeok
authors.initials: H
authors.lastname: Kwon
authors.affiliation: Department of Life Science and Biotechnology, Korea University, Seoul 136-701, Republic of Korea. Electronic address: kwook@korea.ac.kr.
authors.forename: Wook
authors.initials: W
authors.lastname: Kim
authors.affiliation: Department of Bioresource Sciences, Andong National University, Andong 760-749, Republic of Korea. Electronic address: hosanna@andong.ac.kr.
authors.forename: Yonggyun
authors.initials: Y
authors.lastname: Kim
mesh_terms: D000818:Animals; D017606:Chlorine Compounds / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D009036:Moths / Q000187:drug effects* / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D010087:Oxides / Q000633:toxicity*; D054464:Peroxiredoxins / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D017606:Chlorine Compounds; D007306:Insecticides; D010087:Oxides; D017382:Reactive Oxygen Species; C025109:chlorine dioxide; D054464:Peroxiredoxins; D013482:Superoxide Dismutase
keywords: Chlorine dioxide; Fumigant; Hemocyte; MTT assay; Plodia interpunctella