Multi-omics characterization of toxin expression and producing organs in the predatory gastropods Monoplex corrugatus and Stramonita haemastoma

Abstract

Este estudio caracteriza los sistemas productores de toxinas de los gasterópodos marinos depredadores Monoplex corrugatus y Stramonita haemastoma mediante un enfoque multi-ómico basado en transcriptómica y proteómica. Se identificaron respectivamente 1.777 y 2.565 posibles toxinas siendo las glándulas salivales el principal órgano de producción de veneno. La anotación manual confirmó la presencia de numerosas proteínas bioactivas y reveló diferencias significativas entre especies y tejidos. Asimismo, el estudio reveló la existencia de proteínas conservadas implicadas en el procesamiento del veneno y de toxinas específicas de cada linaje, reflejo de adaptaciones evolutivas particulares. Los resultados amplían el conocimiento sobre la diversidad y evolución de los sistemas de veneno en gasterópodos marinos y ponen de manifiesto el potencial de los enfoques multi-ómicos para el descubrimiento y caracterización de nuevas toxinas.

Background: The exploration of toxin diversity is crucial for understanding the evolutionary adaptation of venomous taxa. Despite being active venomous predators, neogastropods are largely understudied beyond Conidae. This study targets two predatory gastropods, Monoplex corrugatus and Stramonita haemastoma, aiming to characterize their toxin-producing tissues, evaluate the diversity and function of their toxins, and compare gene expression profiles across tissues. Specimens of both species were dissected to isolate multiple replicates of secretory glands and other tissues. Transcriptomic data were complemented by shotgun proteomics for S. haemastoma and used to identify putative toxin genes using the DeTox pipeline. Differentially expressed genes were identified and putative toxins were manually annotated. Results: The study identified 2,565 and 1,777 putative toxins in S. haemastoma and M. corrugatus, respectively. Salivary glands were the major toxin-producing organ in both species, with additional toxin expression in midesophageal and accessory salivary glands. Manual annotation confidently identified 115 –S. haemastoma– and 143 –M. corrugatus– venom proteins, highlighting significant interspecies and inter-tissue differences. Functional categorization revealed the presence of enzymatic and peptide toxins, as well as venom-processing proteins, with M. corrugatus showing expression in non-secretory tissues. Despite their phylogenetic distance, shared orthologs were identified between the two species, namely for venom-processing proteins like calglandulin and disulfide isomerases, suggesting conserved functions. Toxins unique to each species analyzed, including echotoxins and plancitoxins in M. corrugatus, indicate lineage-specific venom adaptations. Proteomic validation supported transcriptomic predictions in S. haemastoma. Conclusions: These findings underscore the value of multi-omics approaches for toxin discovery and for investigating the complexity of gastropod venom evolution and expand our understanding of how venom systems evolve and diversify in marine snails, highlighting both shared and unique toxin strategies that may reflect different ecological adaptations.