Characterization of tasar silkworm Antheraea mylitta drury (Saturniidae: Lepidoptera) midgut bacterial symbionts through metagenomic analysis

Information on the bacterial symbiosis/interactions is lacking in tasar silkworm Antheraea mylitta Drury. The detailed midgut bacterial diversity and their functions were elucidated for the first time in tasar silkworm. Taxonomic annotation of fifth instar larval midgut bacteria of three major ecoraces namely Daba, Modal and Raily was carried out using Illumina Next-Generation Sequencing. The dominant phyla and genus are Proteobacteria and Pseudomonas respectively, irrespective of the ecorace. The bacterial diversity & functions varied among ecoraces due to diet & geography. Predictive functional analysis through PICRUSt, revealed many important functional roles of gut bacteria in digestion, detoxification, amino-acid synthesis, etc. Metabolic pathways related to metabolism of amino acids, carbohydrates, lipids, plant secondary metabolites and membrane transport are the most significant gut bacterial functions. Loss of native gut bacteria following the antibiotics treatment reduced the silkworm fitness. We found significant symbiotic role between silkworm and midgut bacteria mediated through various physiological functions. The information obtained from this study helps to enrich the knowledge and could contribute to engineer the functions for the enhancement of silk yield and quality through probiotics.