Mosquito gut ecosystem: Metagenomic and metabolomic configuration

The mosquito gut ecosystem accommodates a complex microbial assemblage. The dynamic gut microbiome profoundly affects various mosquito life traits, including fecundity and immunity. To characterize the metagenomic structure, functional repertoire and metabolic configuration of the gut microbiome, we generated 15Gbp metagenomic DNA- and RNA-seq data from the guts of adult mosquito Anopheles gambiae. Using an assembly-based pipeline, a 37.1 Mbp metagenomic reference was compiled, which included 49,000 contigs. Similarity based taxonomic classification recognized at least 6 phyla, predominant taxa included Proteobacteria (Enterobacteriacea, Psedomonadaceae and Acetobacteracea) and Bacteroidetes (Flavobacteriaceae). The functional annotation recognized 23,550 coding sequences. Among them 42% were assigned into ~700 subsystems. Metabolic reconstruction predicted 1658 reactions and 1266 compounds. In addition to the presence of many ABC transporters, there are large numbers of TonB dependent transporters and polysaccharide utilization loci, constituting uptake systems for iron, vitamin B 12 and various biopolymers.  The presence of large capacity of resistance to antibiotics and toxic compounds may represent a defense strategy for maintaining community stability.  The metagenomic reference was further used for mapping RNA-seq reads to decipher context dependent community functions, which was exemplified by metatranscriptomic analysis of the sugar-fed and blood-fed guts. Metabolic profiling revealed intriguing connections  among metabolism, stress response and immunity. The metagenomic and metabolomic data provide insights into the taxonomic and functional configuration in the mosquito gut ecosystems.