Complete genome sequence of Anabaenopsis sp. NIES-4685 (Nostocales, Cyanobacteriota) from Lake Abashiri, a brackish water lake in Japan

Abstract

A high-quality complete genome sequence of Anabaenopsis sp. NIES-4685, isolated from Lake Abashiri, a brackish water lake in Japan, was obtained using Oxford Nanopore sequencing technology. The genome assembly yielded a single 4.6 Mbp circular genome and a 12 kbp putative plasmid. Phylogenomic analyses indicated that Anabaenopsis sp. NIES-4685 clustered with other Anabaenopsis strains, confirming the morphology-based classification of this strain. The genome contains putative genes for osmolytes sucrose and trehalose syntheses, which is consistent with its brackish water origin and low salt tolerance. In agreement with its taxonomic features, it carries genes for nitrogen fixation (nifDKH) and gas vesicle synthesis (gvp). Additionally, genes encoding mycosporine-like amino acids, which function as UV protectants, were identified. Unexpectedly, no genes encoding non-ribosomal peptide synthetases or polyketide synthases, which are key enzymes in the biosynthesis of diverse secondary metabolites, including cyanotoxins, were identified. The strain and its complete genome data will be useful for further ecophysiological, toxicological, and taxonomic investigations of Anabaenopsis and related genera in the order Nostocales.