Integrative multi-omics characterization of the gut microbiome in Pila globosa: functional insights into nutrient...

Pila globosa, a freshwater snail endemic to Indian aquatic ecosystems, plays a pivotal role in nutrient cycling and organic matter turnover. In this study, we present the first integrative multi-omics characterization of its gut microbiome using shotgun metagenomics, metaproteomics, and genome-resolved analyses. The gut microbiota was taxonomically diverse yet compositionally stable, dominated by Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, with core genera including Pseudomonas, Clostridium, Bacillus, and Streptomyces. Alpha diversity metrics (Shannon = 4.22 ± 0.15; Simpson = 0.90 ± 0.01) and low Bray-Curtis dissimilarity (0.12-0.15) indicated a conserved core microbiome across replicates. Functional profiling through HUMAnN2 and metaproteomic validation revealed enrichment of pathways related to carbohydrate metabolism, short-chain fatty acid (SCFA) synthesis, amino-acid biosynthesis, and oxidative phosphorylation, reflecting the community's contribution to host nutrition and metabolic balance. Genes and proteins associated with xenobiotic degradation (benzoate, toluene metabolism) and oxidative stress response (superoxide dismutase, catalase, glutathione S-transferase) were abundant, suggesting microbial support for redox regulation and detoxification. Twelve high-quality metagenome-assembled genomes (MAGs) reconstructed from dominant taxa encoded traits for secondary metabolite production, metal resistance, and stress tolerance, underscoring their ecological versatility. Together, these results establish a foundational reference for understanding the functional potential of the P. globosa gut microbiome and its possible role in nutrient transformation and pollutant processing in freshwater systems. The study provides baseline data for future comparative and ecotoxicological investigations of gastropod holobionts.