Genomic and secondary metabolites of the marine cyanobacterium Capilliphycus salinus ALCB114379

Assembling high-quality genomes from underexplored environments can be helpful for understanding microbial diversity and identifying novel species. The Cyanobacterium type strain Capilliphycus salinus ALCB114379 is a representative of Oscillatoriales order isolated from a supralittoral zone of the south Atlantic Ocean in Brazil, an ecotone characterized by significant environmental fluctuations due to its transitional nature between the tidal and terrestrial environments. Here, we present its genome assembled into a single contig and circularized, with a total size of 7.7 Mb and 99.67% completeness. The genome has 6204 protein-coding genes, including several involved in the biosynthesis of secondary metabolites. Despite being a homocytous genus, C. salinus ALCB114379 possesses a gene cluster for the biosynthesis of molybdenum-type nitrogenase, indicating a potential for N₂ fixation. Additionally, the genome contains other gene clusters related to the biosynthesis of biotechnologically relevant compounds, such as microcyclamide (mca), a cytotoxic cyanopeptide, and mycosporine-like amino acids (MAAs), with photoprotective and antioxidant functions. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis showed the detectable production of three MAAs, with shinorine being the most abundantly produced compared with porphyra-334 and palythine. This work provides insights into the Cyanobacteria phylogenomics and metabolism, highlighting the potential of C. salinus ALCB114379 as a source of specific metabolites for biotechnological applications.