Hypoxic environment protects cowpea bruchid (Callosobruchus maculatus) from electron beam irradiation damage. Issue 3 (8th October 2018)

• Record Type: Journal Article
• Authors: Wang, Lei; Cheng, Weining; Meng, Jia; Speakmon, Mickey; Qiu, Jiangping; Pillai, Suresh; Zhu‐Salzman, Keyan
• Is Part Of: Pest management science. Volume 75:Issue 3(2019)
• Page Start: 726
• Page End: 735
• Publication Date: 2018-10-08
• Subjects: Callosobruchus maculatus -- hypoxia -- eBeam irradiation -- emergence rate -- reoxygenation -- antioxidant enzymes; Pests -- Control -- Periodicals; Pesticides -- Periodicals; 632.9
• DOI: 10.1002/ps.5172
• Languages: English
• ISSNs: 1526-498X

Abstract

Abstract: BACKGROUND: Electron beam (eBeam) irradiation and hermetic storage are safe and effective technologies to protect stored products. Although hypoxic environment improves performance of some irradiated insects, whether hypoxia affects irradiation of storage insects and impacts pest control efficacy remains to be investigated. RESULTS: Using cowpea bruchid ( Callosobruchus maculatus ) larvae, we showed that, relative to eBeam irradiation under normoxia, the adult emergence rate increased substantially if they were exposed to hypoxia prior to and during eBeam treatment. Conversely, exposure to hypoxia only after eBeam irradiation did not have this protective effect. eBeam irradiation caused an increase in reactive oxygen species (ROS) in normoxic larvae but not in hypoxic larvae. The activity of citrate synthase, a pace‐making enzyme in the citric acid cycle, was suppressed under hypoxia but resumed normal function within hours of reoxygenation, suggesting that reduced mitochondrial activity, and thus less ROS production under hypoxia increased insect tolerance to irradiation. Furthermore, reoxygenation accelerated eBeam‐induced glutathione‐S‐transferase activation and potentiated eBeam‐enhanced catalase activities. Faster and stronger detoxification capacity in eBeam‐irradiated, hypoxic larvae may have protected them from oxidative damage. CONCLUSION: Hypoxic environment enhanced radiotolerance of bruchid larvae, presumably due to limited ROS production and elevated antioxidant enzymatic activities after reoxygenation. © 2018 Society of Chemical Industry Abstract : Hypoxia exposure increased bruchid tolerance to subsequent irradiation. Limited reactive oxygen species (ROS) production and elevated antioxidant enzymatic activities might explain the protection of hypoxia exposure from the electron beam (eBeam) damage to bruchids larvae.