Immune-related gene profiles and differential expression in the grey garden slug Deroceras reticulatum infected with the parasitic nematode Phasmarhabditis hermaphrodita

Authors: HAFEEZ, MUHAMMAD - Oregon State University; MCDONNELL, RORY - Oregon State University; COLTON, ANDREW - Oregon State University; HOWE, DANA - Oregon State University; DENVER, DEE - Oregon State University; MARTIN, RUTH - Oregon State University; Choi, Man-Yeon

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2024
Publication Date: 4/26/2024
Citation: Hafeez, M., Mcdonnell, R., Colton, A., Howe, D., Denver, D., Martin, R., Choi, M.Y. 2024. Immune-related gene profile and differential expression in the grey garden slug Deroceras reticulatum infected with the parasitic nematode Phasmarhabditis hermaphrodita. Insects. 15(5):311. https://doi.org/10.3390/insects15050311.
DOI: https://doi.org/10.3390/insects15050311

Interpretive Summary: Slugs are a worldwide problem in agriculture. In Oregon, the economic impact by pest slugs is estimated to cost the seed industry more than $50 million annually. Currently, the most common slug control methods rely on chemical pesticides, which are unsustainable for environmental and human health. This study investigated and analyzed the differential gene expression profiles of the nematode-infected slugs, and compared them to the uninfected slugs, and identified the genes associated with immunity in the grey garden slug. The results provide a starting point for understanding the molecular mechanism of immune genes and physiological pathways, facilitating the identification of biological targets for slug management strategies in the field.

Technical Abstract: The grey garden slug (Deroceras reticulatum), is a common terrestrial slug native to Europe with global distribution including North America, stands out as the predominant species and is commonly considered the most severe pest of vegetables and field crops. In this study, we describe RNA-seq expression profiling of D. reticulatum whole body response to nematodes infection. Denovo transcriptome was generated from the whole body of the slug-control and slug-nematode. Comparison of gene expression levels between slug-control vs slug-nematode revealed that out of 1,43,576 unigenes, there were total of 95770 regulated unigenes, (3084 (3%) up-regulated and 6761 (6%) down-regulated} in Slug-control and slug-nematodes infection. Total number of up- and down-regulated DEGs and annotated DEGs in Slug-nematode compared to Slug-control group. To further investigate the biological functions of different expression genes (DEGs), gene ontology (GO) and functional enrichment analysis were performed to map all the DEGs to terms in the GO, eukaryotic Ortholog Groups of proteins (KOG) and Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG) database. Among these DEGs, many genes and related pathways involved in immunity were identified in slug-control vs slug-nematode. These included genes mainly belonged to the Toll, Imd, JNK, scavenger receptors (SCRs), C-type lectins (CTLs), immunoglobulin-like domains and JAK/STAT63 signaling pathways. To confirm the gene expression patterns identified by the RNA-seq data, the transcript levels of 18 immune related DEGs were examined by quantitative real-time PCR (qRT-PCR). The results showed that the DEGs obtained from the De novo transcriptome sequencing data were in accordance with the gene expression profiles from RNA-Seq data. Our finding provides insights into the immune response of D. reticulatum underling the infection of nematodes which is valuable to understand how nematode affects the immune system of D. reticulatum and provide new methods to control insect pests by using pathogenic nematodes as a biological insecticide.