Biochemical basis of synergism between pathogenic fungus Metarhizium anisopliae and insecticide chlorantraniliprole in Locusta migratoria (Meyen)

• Published in: Scientific reports 2016-06, Vol.6 (1), p.28424-28424, Article 28424
• Main Authors: Jia, Miao, Cao, Guangchun, Li, Yibo, Tu, Xiongbing, Wang, Guangjun, Nong, Xiangqun, Whitman, Douglas W., Zhang, Zehua
• Format: Article
• Language: English
• Subjects: 631/326/193/2544; 631/45/607; Amidohydrolases - genetics; Animals; Assaults; Calcium - metabolism; Chitinases; Detoxification; Drug Synergism; Enzymatic activity; Enzymes; Esterases - genetics; Fungi; Gene Expression Regulation, Enzymologic - drug effects; Glutathione Transferase - genetics; Homeostasis; Humanities and Social Sciences; Infections; Insect Proteins - genetics; Insecticides; Insecticides - pharmacology; Insects; Locusta migratoria - drug effects; Locusta migratoria - enzymology; Locusta migratoria - microbiology; Metarhizium - physiology; Monophenol Monooxygenase - genetics; Mortality; multidisciplinary; ortho-Aminobenzoates - pharmacology; Pathogens; Pest control; Phenols; Poisoning; Science; Science (multidisciplinary); Synergism; Toxicity; Xenobiotics
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep28424

We challenged Locusta migratoria (Meyen) grasshoppers with simultaneous doses of both the insecticide chlorantraniliprole and the fungal pathogen, Metarhizium anisopliae . Our results showed synergistic and antagonistic effects on host mortality and enzyme activities. To elucidate the biochemical mechanisms that underlie detoxification and pathogen-immune responses in insects, we monitored the activities of 10 enzymes. After administration of insecticide and fungus, activities of glutathione- S -transferase (GST), general esterases (ESTs) and phenol oxidase (PO) decreased in the insect during the initial time period, whereas those of aryl acylamidase (AA) and chitinase (CHI) increased during the initial period and that of acetylcholinesterase (AChE) increased during a later time period. Activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) decreased at a later time period post treatment. Interestingly, treatment with chlorantraniliprole and M. anisopliae relieved the convulsions that normally accompany M. anisopliae infection. We speculate that locust mortality increased as a result of synergism via a mechanism related to Ca 2+ disruption in the host. Our study illuminates the biochemical mechanisms involved in insect immunity to xenobiotics and pathogens as well as the mechanisms by which these factors disrupt host homeostasis and induce death. We expect this knowledge to lead to more effective pest control.