Genomic insights into biosynthetic gene cluster diversity and structural variability in marine bacteria.

Marine bacteria are a rich source of bioactive compounds, many of which are encoded by biosynthetic gene clusters (BGCs). Understanding the diversity and structural variability of these clusters can provide insights into novel natural product discovery. This study analyzed 199 marine bacterial genomes from 21 species, screening for BGCs using antiSMASH 7.0. Phylogenetic relationships were assessed using rpoB gene-based analysis, and BGC clustering was performed using BiG-SCAPE. The study focused on NI-siderophore BGCs encoding vibrioferrin, assessing genetic and structural variations across Vibrio harveyi, Vibrio alginolyticus, and Photobacterium damselae. A total of 29 BGC types were identified, with non-ribosomal peptide synthetases (NRPS), betalactone, and NI-siderophores being predominant. Vibrioferrin-producing BGCs exhibited high genetic variability in accessory genes, while core biosynthetic genes remained conserved. Clustering analysis showed that at 10% similarity, vibrioferrin BGCs formed 12 families, while at 30% similarity, they merged into a single gene cluster family (GCF). This study highlights the biosynthetic diversity of marine bacteria and the structural plasticity of vibrioferrin BGCs, which may influence iron-chelation properties and microbial interactions. The findings contribute to natural product bioprospecting and underscore the potential for discovering novel bioactive compounds from marine microbes.