Polyphagous insect Olepa sps . feeding on cardenolide rich Calotropis gigantea (L.) leaves and detoxification mechanism involving GST

Krishnamanikumar Premachandran; Thanga Suja Srinivasan

doi:10.1016/j.heliyon.2022.e10596

Polyphagous insect Olepa sps . feeding on cardenolide rich Calotropis gigantea (L.) leaves and detoxification mechanism involving GST

Heliyon. 2022 Sep 16;8(9):e10596. doi: 10.1016/j.heliyon.2022.e10596. eCollection 2022 Sep.

Authors

Krishnamanikumar Premachandran¹, Thanga Suja Srinivasan¹

Affiliation

¹ Centre for Climate Change Studies, International Research Centre, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India.

Abstract

Cardenolides, a group of cardiac glycosides are potent inhibitors of Na⁺/K⁺ ATPase pump in mammals, animals including insects. Some insects can circumvent the toxicity of cardenolides by mechanisms like target site resistance and metabolic resistance resulting in enhanced tolerance or adaptation. In this paper, we report an intriguing observation of a polyphagous feeder feeding gregariously on the leaves of Calotropis gigantea (L.) without any apparent adverse effect. No choice feeding assay showed higher larval biomass and reduced number of days to develop on C. gigantea leaves compared to Ricinus and banana. We found the activity of GST higher in C. gigantea fed larva and HR LC-MS analysis of Olepa sps. revealed the presence of glutathione-strophanthidin conjugate in larval body tissue. In silico molecular simulation results confirmed strong interaction between delta variant GST and glutathione-strophanthidin complex. The sequestration site and cost benefit of glutathione-strophanthidin sequestration in body tissues of Olepa sps. needs further investigation.

Keywords: Calotropis gigantea; Detoxification; GST; Glutathione-strophanthidin conjugate; Olepa; Sequester; Strophanthidin.