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In nature, secondary metabolites mediate interactions between microorganisms residing in complex microbial communities. However, the degree to which community dynamics can be linked to secondary metabolite potential remains largely unknown. In this study, we address the relationship between community succession and secondary metabolism variation. We used 16S and 18S rRNA gene and adenylation domain amplicon sequencing, genome-resolved metagenomics, and untargeted metabolomics to track the taxons, biosynthetic gene clusters, and metabolome dynamics in situ of microorganisms during marine biofilm succession over 113 days. Two phases were identified during the community succession, with a clear shift around Day 29, where the alkaloid secondary metabolites, pseudanes, were also detected. The microbial secondary metabolite potential changed between the phases, and only a few community members, including Myxococotta spp., were responsible for the majority of the biosynthetic gene cluster potential in the early succession phase. In the late phase, bryozoans and benthic copepods were detected, and the microbial nonribosomal peptide potential drastically decreased in association with a reduction in the relative abundance of the prolific secondary metabolite producers. Conclusively, this study provides evidence that the early succession of the marine biofilm community favors prokaryotes with high nonribosomal peptide synthetase potential. In contrast, the late succession is dominated by multicellular eukaryotes and a reduction in bacterial nonribosomal peptide synthetase potential.

Every host species and organism provides a unique environmental niche contributing to the overall diversity of microbial ecosystems from the intestine of an animal to the oceans and forests of our planet. The study of host–microbiota interactions has long focused on the well-established effects the microbiota has on its host. In contrast, little focus has been allocated to the role of the host in these intricate interactions. However, understanding the role of the host may well be an essential key to understanding the complexity of the relationship between the host and its microbiota. In this study, we present a model in which the effects of host genes on the microbiota can be elucidated and how such genetic effects may shape host-associated microbiota. We demonstrate a hologenomic approach implementing the CRISPR/Cas system in the zebrafish model to combine the effects of a host gene with 16S metabarcoding and metabolomics data. We show that knocking out the gene coding for the rate-limiting enzyme in melanogenesis, tyrosinase (tyr), correlates with changes in the intestinal microbiota of zebrafish and differences in the abundance of specific metabolites illustrating the value of our model for studying the impact of host genes on the composition and function of the intestinal microbiota.