The modulation effect of the Steinernema carpocapsae - Xenorhabdus nematophila complex on immune-related genes in Drosophila suzukii larvae

Multi-Omics Analysis of Curculio dieckmanni (Coleoptera: Curculionidae) Larvae Reveals Host Responses to Steinernema carpocapsae Infection

The hazelnut weevil larvae (Curculio dieckmanni) is a major pest of nut weevils, spending part of its life cycle in the soil and causing significant damage to hazelnut crops. Moreover, its concealed feeding behavior complicates effective control with chemical insecticides. The entomopathogenic nematode Steinernema carpocapsae, which efficiently kills weevil larvae, offers a promising biological control agent. To investigate the molecular responses of hazelnut weevil larvae to nematode infection, we employed integrated transcriptomic and proteomic analyses following infection by S. carpocapsae. Our results revealed substantial alterations in gene expression, particularly the upregulation of immune-related transcripts such as antimicrobial peptides (AMPs) and stress-responsive proteins like heat shock protein 70 (HSP70). Furthermore, significant metabolic reprogramming occurred, marked by the downregulation of carbohydrate metabolic pathways and activation of energy conservation mechanisms. Although we observed an overall correlation between mRNA and protein expression levels, notable discrepancies highlighted the critical roles of post-transcriptional and post-translational regulatory processes. Collectively, these findings advance our understanding of the molecular interaction between insect hosts and pathogenic nematodes and contribute valuable knowledge for enhancing the effectiveness of EPN-based pest management strategies.

Global Trends in Research on Biological Control Agents of Drosophila suzukii: A Systematic Review

It is essential to consolidate knowledge on biological control agents (BCAs) for Drosophila suzukii, to identify gaps, evaluate the effectiveness of existing strategies, and guide future research toward sustainable pest management. The biological control of SWD has been explored through various BCAs, focusing on parasitoids, predators, and entomopathogens. We conducted a systematic review using Web of Science and Scopus (2012-2023) to investigate global research on BCAs of SWD. Our goal was to synthesize and categorize the current scientific production, addressing questions such as (1) publication numbers per BCA group and species, (2) key BCAs, (3) common methodologies (laboratory, field, greenhouse, or combined), (4) research scope, (5) effectiveness of BCAs, and (6) countries conducting research. We found 585 records, 184 of which were suitable for analysis. The most studied BCAs are parasitoids, comprising 64% of publications, with Trichopria drosophilae and Pachycrepoideus vindemmiae being the most researched, followed by Leptopilina japonica and Ganaspis kimorum. Entomopathogens and predators represent 26% and 7% of publications, respectively. Studies under controlled conditions predominate, and surveys, identifications, and characterization of natural enemies are the main research foci, followed by conservation biological control showing the highest effectiveness.

Analysis of the immune transcriptome of the invasive pest spotted wing drosophila infected by Steinernema carpocapsae

Drosophila suzukii is a pest of global concern due to its great impact on several crops. The entomopathogenic nematode Steinernema carpocapsae was highly virulent to the larvae of the fly although some immune mechanisms were triggered along the infection course. Thus, to understand the gene activation profile we performed a comparative transcriptome of D. suzukii larvae infected with S. carpocapsae and Xenorhabdus nematophila to map the differentially expressed genes involved in the defence response. The analysis exposed the induction of genes involved in the humoral response such as the antimicrobial peptides and pattern-recognition receptors while there was a suppression of the cellular defence. Besides, genes involved in melanisation, and clot formation were downregulated hindering the encapsulation response and wound healing. After the infection, larvae were in a stress condition with an enrichment of metabolic and transport functionalities. Concerning the stress response, we observed variations of the heat-shock proteins, detoxification, and peroxidase enzymes. These findings set a genetical comprehensive knowledge of the host-pathogen relation of D. suzukii challenged with S. carpocapsae which could support further comparative studies with entomopathogenic nematodes.