Metabolic fingerprint establishes ecological linkage between polychaete gut microbes with surrounding benthic...

In gut-associated symbiosis, microbes play a pivotal role in shaping the habitat and diet preferences of the host. In intertidal deposit-feeding polychaetes, gut microbial assemblages are influenced by both water and sediment biota. In the present study, the metabolic profiling of gut microbial communities of Perinereis sp. was compared with its surrounding environmental microbiome. Effective utilization of amine, amino acids, and carbohydrate substrates by gut microbes was noticed within 48 h of incubation. Moreover, it reached an average well colour development of 0.54 at 120^th hour of incubation. Low Gini coefficient (0.332) revealed a substrate-generalized communities with diverse metabolism pathways persist in the gut. The multi-level pattern analysis indicated some important substrates that were commonly utilized by gut as well as sediment microbes. Similarity percentage revealed maximum resemblance (64.1%) of gut microbes with its sediment which possibly explained by their deposit-feeding trait and diet preferences. Further, a generalized additive model was applied to study the non-linear trend in time-dependent utilization of carbon guilds by different microbial communities. The results overall indicate the functional overlaps in utilization pattern and possibly explain how polychaete gut microbiome share functional similarity with environmental microbiome with maintaining a distinct community structure. The capacity of utilizing wide varieties of substrate denote high metabolic plasticity of gut microbes which may help in host's survival in the organically enriched mudflat. Furthermore, overlaps in substrate utilization reveal that common environmental factors drive the ecological similarity between gut and sediment microbes.