The metagenome of Caracolus marginella gut microbiome using culture independent approaches and shotgun sequencing

Studies underestimate the microbial diversity and genotypic traits in the snails' microbiome. Caracolus marginella, a land snail native to Caribbean islands, can adapt to different environments. Our research focused on the generation of a metagenomic library from C. marginella gut, to further explore the diversity and functional traits. Thirty specimens of C. marginella were collected from the four regions of Puerto Rico. High molecular weight (40 kb) metagenomic libraries were generated using a direct DNA isolation method. DNA was end-repaired and ligated into a pCCFOS1 fosmid vector; then, the cloned DNA was transduced into Escherichia coli EPI300. The master pool library contains approximately 60,200 clones and restriction enzyme digestion showed that 90% of the library contains insert. After removing the fosmid and host genome sequences, 567,015 sequences were analyzed using the MG-RAST online server. The Bacteria domain was the most abundant (82.15%), followed by viruses (16.49%), eukaryotes (0.83%) and archaea (0.31%). The Proteobacteria (51.47%) was predominant in the gut environment, followed by unidentified virus (16.28%), and Actinobacteria (8.52%). Escherichia coli, Streptomyces avermitilis, and Burkholderia sp. were the most abundant species present. Subsystem functional analysis showed that 35.00% of genes belong to transposable elements, 10.00% of genes belong to clustering-based subsystems, 4.00% of genes belong to the production of cofactors and secondary metabolites, and 2.00% resistance to antibiotics and toxic compounds. The data generated in this research is the first metagenomic examination of a snail gut in Puerto Rico, and will serve as a baseline to start understanding of C. marginella gut microbiome.