Arthrospira (Spirulina) plantensis is a filamentous non-N2-fixing cyanobacterium and known to be an important organism for industrial application and as a food supply.
The strain NIES-39 was originally isolated from a saline lake in Africa and grows under severe conditions such as high salt and alkaline pH. Despite the importance in industrial applications,
little is known about the biology and genetic system of A. platensis and related cyanobacterial species because of, at least in part, the difficulty in genetic transformation.
Almost complete genome sequence of A. platensis NIES-39 was determined. Optical mapping analysis revealed that the genome consists of a single circular chromosome of 6.8Mb.
A total of 6,630 protein-coding genes, two sets of rRNA genes and 40 tRNA genes were predicted and annotated. Of the protein-coding genes, 78% are similar to those of other
organisms and the remaining 22% are currently unknown.
Comparative genome analysis with other sequenced cyanobacterial genomes highlighted genes specific to filamentous cyanobacteria. Surprisingly, almost 10% of the genome (612 kb)
is composed of group II introns, phage-like sequences, insertion elements and other types of repetitive sequences. In addition, the genome harbors many pseudogenes, suggesting
that the genome is undergoing rapid evolution to adapt to environmental conditions. The genome was found to contain a number of restriction-modification systems for protecting
the genome from exogenous DNA elements. These results may provide important clues for post-genome studies, including the development of genetic transformation system, and for further industrial utilization.
|We have analyzed the proteome of Arthrospira platensis NIES-39 by using the following method; 2D-PAGE followed by N-terminal amino acid sequencing.
|Genomic size||6,788,435 bp|
|G+C content||43.65 %|
|Number of ORFs assigned||6,630|
|Percentage of the coding regions||81.25 %|
|Percentage of the intronic regions||0.00 %|
|Number of rRNA genes||
|Number of tRNA genes||
|Number of other features
The nucleotide sequence of the A. platensis NIES-39 genome was determined by the whole genome shotgun sequencing method as in the case of other organisms analyzed at NITE-DOB.