Genomic Characteristics of the Toxic Bloom-Forming Cyanobacterium Microcystis aeruginosa NIES-102

摘要

Microcystis aeruginosa, a bloom-forming cyanobacterium distributed mainly in freshwaterenvironments, can be divided into at least 12 groups (A–K and X) based on multi-locus phylogeneticanalyses. In this study, we characterized the genome of microcystin-producing M. aeruginosaNIES-102, assigned to group A, isolated from Lake Kasumigaura, Japan. The complete genomesequence of M. aeruginosa NIES-102 comprised a 5.87-Mbp circular chromosome containing 5,330coding sequences. The genome was the largest among all sequenced genomes for the species. In acomparison with the genome of M. aeruginosa NIES-843, which belongs to the same group, themicrocystin biosynthetic gene cluster and CRISPR-Cas locus were highly similar. A synteny analysisrevealed small-scale rearrangements between the two genomes. Genes encoding transposases weremore abundant in these two genomes than in other Microcystis genomes. Our results improve ourunderstanding of structural genomic changes and adaptation to a changing environment in thespecies.