| The cyanobacteria Microcystis aeruginosa are widely distributed in temperate lakes,which gain extensive attention due to their capacity of producing microcystin.Understanding the genome characteristics of M.aeruginosa will help to elucidate the mechanism of environmental adaptation at the molecular level.M.aeruginosa Chao 1910(termed Chao 1910 for short)was isolated and identified from Chaohu Lake.Through sequencing and assembling by third-generation sequencing,we obtained the whole genome sequence of Chao 1910.Based on the genome sequence,we analyzed the genomic characteristics and phosphorus metabolism pathway of Chao 1910.The genome size of M.aeruginosa Chao 1910 is 5,669,822 bp,with the GC content of 42.2%,and 5,659 open reading frames can be annotated.Compared to the previously reported Microcystis strains with complete genome sequence,Chao 1910 is most similar to M.aeruginosa NIES-843.Despite 10 secondary metabolite biosynthetic gene clusters in Chao 1910 genome can be predicted,the microcystin synthesis gene cluster(mcy)is absent.Chao 1910 genome also contains 4 possible prophage regions.According to homology analysis,genes in these regions may be derived from different phages,suggesting the complexity of Chao 1910 genome.The genes of major metabolic pathways such as glycolysis,pentose phosphate pathway and nucleotide synthesis are highly conserved.Chao 1910 encodes complete pathways of phosphate transport,phosphate absorption,polyphosphate synthesis/decomposition and other efficient phosphorus utilization.Through transcriptional analysis,we verified the transcriptional effects of vital genes for phosphorus uptake and storage under different phosphorus condition.Chao 1910 is the first strain of M.aeruginosa in Chaohu Lake with the whole genome sequence.Given that M.aeruginosa are the dominant cyanobacteria in Chaohu Lake,our work will help to reveal the molecular mechanism of competitive advantages and provide a basis for controlling the bloom in Chaohu Lake. |
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