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

Abstract

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 Ca2+ 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.

Toxicological and biochemical basis of synergism between the entomopathogenic fungus Lecanicillium muscarium and the insecticide matrine against Bemisia tabaci (Gennadius)

“…The treatment of B. tabaci with a combination of matrine and L. muscarium resulted in a significant reduction of CarE and GSTs activities throughout the experimental period. These results are in line with the findings of Jia et al 23. who have shown a similar reduction of enzyme activity in Locusta migratoria following joint application of chlorantriniliprole and Metarhizium anisopliae .…”

“…In our study, the activities of antioxidant enzymes (SOD, CAT, and POD) increased during the initial 3 days followed by a decrease when treated with L. muscarium alone. On the other hand, when matrine was applied in combination with L. muscarium , SOD and POD activities increased during the initial 3 days but CAT activities started to decrease after 24 h. This decrease in CAT activity can have a direct relationship with the accumulation of superoxide radicals produced during the destruction process23. The decreased activities of antioxidant enzymes (SOD, CAT, and POD) during the later experimental period can result in a reduced elimination of ROS which in turn can denature different biomolecules of the insect body.…”

“…Our results showed an increase in CHI activitythroughout the experimental period following L. muscarium application whereas reduction in CHI activities was observed after 3 days of matrine application or joint application of matrine and L. muscarium . We speculate that the joint application of matrine and L. muscarium disrupted the insect moulting process by creating an imbalance of chitinase production which is an essential enzyme required for moulting23.…”

“…The co-toxicity coefficients for the mixed formulation were calculated after calculating the LC 50 of each component in the mixture. Calculations were performed by using the following equations (Equations 1) described by Jia et al 23…”

Синергетическое действие пиретроидного инсектицида и энтомопатогенного гриба на Daphnia magna Straus

“…Полученные данные свидетельствуют о том, что сублетальные концентрации химического инсектицида эсфенвалерата могут подавлять активность ферментов детоксицирующей системы. В то же время, при микозах отмечается тенденция к подъему уровня данных ферментов у дафний, что согласуется с работами по грибным инфекциям у ряда наземных насекомых, а именно: саранчовых, чешуекрылых и жесткокрылых (Serebrov et al, 2006;Dubovskiy et al, 2012;Tomilova et al, 2016;Jia et al, 2016;Yaroslavtseva et al, 2017;Kryukov et al, 2017). При комбинированном действии гриба и эсфенвалерата мы наблюдали (по крайней мере через 24 часа после обработки) «сдерживание» активации детоксицирующих ферментов под действием инсектицида, а в ряде случаев комбинированная обработка приводила к падению активности ферментов ниже контрольного уровня.…”