Symbiont genomic features and localization in the bean beetle, < em > Callosobruchus maculatus < /em >

In this study, we applied community profiling using 16S rRNA gene sequencing to reveal a highly conserved bacterial assembly shared between larvae and adults. Dominated by Firmicutes and Proteobacteria, this community is localized extracellularly along the epithelial lining of the bean beetle's digestive tract. Our analysis revealed only one species, Staphylococcus gallinarum (phylum Firmicutes), is shared across all developmental stages. Isolation and whole genome sequencing of S. gallinarum from the beetle gut yielded a circular chromosome (2.8 Mb) and one plasmid (45 kb). The strain encoded complete biosynthetic pathways for the production of B vitamins and amino acids, including tyrosine, which is increasingly recognized as an important symbiont-supplemented precursor for cuticle biosynthesis in beetles. A CAZyme search revealed the genome codes for a number of carbohydrate active enzymes, reflecting the nutritional ecology of their herbivorous host. The ontogenic conservation of the gut microbiota in the bean beetle - featuring a 'core' community composed of S. gallinarum - may be indicative of an adaptive role for the host. In clarifying symbiont localization and metabolic potential, we further our understanding and study of a costly pest of stored products.IMPORTANCEFrom supplementing essential nutrients to detoxifying plant secondary metabolites and insecticides, bacterial symbionts are a key source of adaptations for herbivorous insect pests. Despite the pervasivenes...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Source Type: research