Novel insights into plant defensin ingestion induced metabolic responses in the polyphagous insect pest Helicoverpa armigera

Abstract

Lepidopteran insect pest Helicoverpa armigera is one of the most destructive pests of crop plants and several biotechnological approaches are being developed for its control. Plant defensins are small cationic and cysteine-rich peptides that play a role in plant defense. Ingestion of a defensin from Capsicum annuum (CanDef-20) induced a dose-dependent reduction in larval and pupal mass, delayed metamorphosis and also severely reduced fecundity and fertility in H. armigera. To understand the molecular mechanisms of CanDef-20 ingestion-mediated antibiosis in H. armigera larvae, a comparative transcriptomics analysis was carried out. Predominant downregulation of GOs represents serine-type endopeptidases, structural constituents of ribosomes and integral membrane components and differential upregulation of ATP binding, nucleus and translation, while up-regulation of nucleic acid binding represented by transposable elements, were detected. Different isoforms of lipase, serine endopeptidase, glutathione S-transferase, cadherin, alkaline phosphatase and aminopeptidases were found to be upregulated as a compensatory response to CanDef-20 ingestion. In vitro enzyme assays and qPCR analysis of some representative genes associated with vital cellular processes like metamorphosis, food digestion and gut membrane indicated adaptive differential regulations in CanDef-20 fed H. armigera larvae. We conclude that CanDef-20 ingestion affects insect metabolism in a number of ways through its interaction with cell membrane, enzymes, cytoplasmic proteins and triggering transposon mobilization which are linked to growth retardation and adaptive strategies in H. armigera.

Trichoplusia Ni Transcriptomic Responses to the Phytosaponin Aglycone Hederagenin: Sex-related Differences

“…Even though in Drosophila melanogaster, the Ca 2+ -binding protein plays a role in Ca 2+ buffering in photoreceptors (Wiess et al, 2012), calphotin in other insect Orders appears to be regulated by stress. This gene was downregulated in H. armigera caterpillars fed the plant protein defensin and also in P. xylostella caterpillars infected with the entomopathogenic fungi Beauveria bassiana (Wang et al, 2021;Mulla and Tamhane, 2023). In our study, calphotin-like (LOC113505107) was upregulated in male T. ni caterpillars exposed to the lower hederagenin dose (Fig.…”

Insecticidal activities of two fig tree leaf extracts against the cotton pest Spodoptera litura (Fab.) and their impact on the non‐target red worm Eisenia foetida (Savigny)

“…ALP has been linked to chitin metabolism during insect growth and development. It also aids in insect exoskeleton development and plays a role in various physiological processes, such as insect molting (Mulla & Tamhane 2023). Correspondingly, LDH is intricately involved in the interconversion of lactate and pyruvate for energy metabolism, helps regulate the anaerobic and aerobic respiration balance, and supports energy production under diverse environments (Senthil‐Nathan & Kalaivani 2006).…”

Trichoplusia ni Transcriptomic Responses to the Phytosaponin Aglycone Hederagenin: Sex-Related Differences

“…Way2Drug ( http://www.way2drug.com/somp/ ) uses a machine learning approach incorporating data from known structure–activity relationships to predict the modification of novel substrates (Druzhilovskiy et al 2017 ). Xenosite ( https://xenosite.org ) uses publicly available cytochrome P 450 metabolism data of over 680 compounds to build neural networks for predictive models (Matlock et al 2015 ; Zaretzki et al 2013 ; Dang et al 2020 ). SMARTCyp ( https://smartcyp.sund.ku.dk/mol_to_som ) uses the density functional theory determinations to calculate the activation energy of the different residues on the molecule to identify the most reactive atoms (Rydberg et al 2010 ; Olsen et al 2019 ).…”