Genome sequence analysis of phosphorus metabolism pathways of Microcystis aeruginosa Chao 1910 isolated from Chaohu Lake

Abstract:

[Background] Microcystis aeruginosa is ubiquitous in temperate lakes and has aroused wide concern since it is a dominant bloom-forming cyanobacterium capable of producing microcystins. [Objective] To elucidate the central metabolic pathways and the efficient phosphorus-utilizing mechanism in M. aeruginosa Chao 1910 (termed Chao 1910 for short) isolated from Chaohu Lake based on the whole-genome sequence analysis and transcription verification. [Methods] The whole genome sequence was obtained by the third-generation sequencing technique, and the genes encoding the central metabolic pathways, especially the phosphorus metabolic pathways, were annotated. [Results] Chao 1910 had the closest phylogenetic relationship with M. aeruginosa NIES-843 among the Microcystis strains with known full-length genome sequences. The genes involved in the metabolic pathways such as glycolysis, pentose phosphate pathway, and nucleotide synthesis were highly conserved in Chao 1910. The genome of Chao 1910 encoded the complete pathways of phosphate transport, phosphate absorption, polyphosphate synthesis/decomposition, and other efficient phosphorus utilization pathways. Unlike other strains of M. aeruginosa, Chao 1910 did not possess the gene cluster for microcystin synthesis, which indicated that it relied on efficient phosphorus utilization to gain the competitive advantage. [Conclusion] Chao 1910 is the first M. aeruginosa strain with completed sequencing of the whole genome isolated from Chaohu Lake. It helps us to reveal the molecular mechanism of competitive advantage for the bloom-forming cyanobacteria in Chaohu Lake.