Location: Biological Control of Insects ResearchTitle: Parasitization by Scleroderma guani influences expression of superoxide dismutase genes in Tenebrio molitor Author
Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2014
Publication Date: 9/1/2014
Citation: Zhu, J., Ze, S., Stanley, D.W., Yang, B. 2014. Parasitization by Scleroderma guani influences expression of superoxide dismutase genes in Tenebrio molitor. Archives of Insect Biochemistry and Physiology. 87(1):40-52. Interpretive Summary: Long-term agricultural sustainability is severely threatened by widespread use of classical insecticides. Threats include increasing resistance to insecticides and sharply decreasing environmental quality. The concept of biological control of insects is a potentially powerful alternative to classical insecticides. Biological control is based on the idea that direct application of certain insect-specific predators, pathogens and parasites can reduce pest insect populations to a point that the pests exert only negligible economic damage. A major problem, however, is that pest insects express potent immune defenses to microbial and parasitic infections. The insect immune defenses limit the usefulness of biological control agents. In this paper, we identified specific proteins that act in insect immunity. Scientists who study insect immunity will use this information in future research designed to reduce insect immune defenses. Ultimately, this research will benefit grain transport and storage operations and the people who consume grain-based foods.
Technical Abstract: Superoxide dismutase (SOD) is an antioxidant enzyme involved in detoxifying reactive oxygen species. In this study, we identified genes encoding the extracellular and intracellular copper-zinc SODs (ecCuZnSOD and icCuZnSOD) and a manganese SOD (MnSOD) in the yellow mealworm beetle, Tenebrio molitor. The cDNAs for ecCuZnSOD, icCuZnSOD and MnSOD respectively encoded 24.55, 15.81 and 23.14 kDa putative polypeptides which possess structural features typical of other insect SODs. They showed 20-94% identity to other known SOD sequences from Bombyx mori, Musca domestica, Nasonia vitripennis, Pediculus humanus corporis and Tribolium castaneum. Expression of these genes was analyzed in selected tissues and developmental stages, and following exposure to Escherichia coli and parasitization by Scleroderma guani. We recorded expression of all three SODs in cuticle, fat body and hemocytes and in the major developmental stages. Relatively higher expressions were detected in late-instar larvae and pupae, compared to other developmental stages. Transcriptional levels were up-regulated following bacterial infection. Analysis of pupae parasitized by S. guani revealed that expression of T. molitor SOD genes were significantly induced following parasitization. It thus appears that these genes act in immune response and host-parasitoid interactions.