Induction of antioxidant and detoxifying systems of Chilo suppressalis Walker after exposure to entomopathogenic fungi

Abstract

The current study aimed to determine antioxidant and detoxifying responses of Chilo suppressalis Walker (Lepidoptera: Crambidae) to Beauveria bassiana (Strains BBRR1, BBAL1, BBLN1, BBLN2), Metarhizium anisopliae and Hirsutella subulata. The interactions of insect humoral immune responses with the entered conidia of entomopathogenic fungi in addition to nodule formation and melanization caused the production of several reactive oxygenate species (ROS), such as hydrogen peroxidase (H2O2), hydroperoxides (ROOH), superoxide radicals (O2−), and hydroxyl radical (OH−). The highest activity of catalase was recorded by BBRR1 and BBAL1, treatment after 48 to 96 h while the larvae treated by BBRR1 showed the highest peroxidase activity. Both ascorbate peroxidase and glucose-6-phosphate dehydrogenase showed the highest activity in the larvae treated by BBRR1 after 48-96 h. The highest concentration of Malondialdehyde reported in the larvae treated by BBRR1, BBAL1 and BBLN1, after 48 hours. The highest activity of general esterases was recorded in the larvae treated by BBRR1 after 48-96 hours. Similar results were recorded in the activity of glutathione-S-transferase but the enzyme had also the highest activity in the larvae treated by BBAL1 and BBLN2 after 48 hours. The larvae treated by BBRR1 and BBLN1 showed the highest activity of acid phosphatase after 72 and 96 hours while the highest activity of alkaline phosphatase was obtained in the larvae only treated by BBRR1 after 48-96 hours. The results clearly revealed that BBRR1 significantly and severely induced antioxidant and detoxifying systems of C. suppressalis larvae implying on virulence and immune induction of BBRR1 against the larvae.