Comparative Genome Analysis of the Closely Related Synechocystis Strains PCC 6714 and PCC 6803

Synechocystis sp. PCC 6803 isthe most popularcyanobacterial model for prokaryotic photosynthesis and for metabolic engineering to produce biofuels. Genomic and transcriptomic comparisons between closely relatedbacteriaarepowerfulapproachestoinferinsightsintotheirmetabolicpotentials andregulatorynetworks. To enable acomparative approach, we generated the draft genome sequenceofSynechocystissp. PCC 6714, aclosely related strain of 6803 (16S rDNA identity 99.4%) that also is amenable to genetic manipulation. Both strains share 2838 protein-coding genes, leaving 845 uniquegenes inSynechocystissp. PCC 6803 and 895 genes in Synechocystis sp. PCC 6714. The genetic differences include a prophage in the genome of strain 6714, a different compositionofthe pooloftransposable elements, anda ∼40 kb genomic island encodingseveral glycosyltransferases and transportproteins.Weverifiedseveralphysiological differencesthat were predicted on the basis of the respective genome sequence. Strain 6714 exhibited a lower tolerance to Zn 21 ions, associated with the lackof acorresponding export system and a lowered potential of salt acclimation due to the absence of a transport system for the re-uptake of the compatible solute glucosylglycerol. These new data will support the detailed comparative analyses of this important cyanobacterial group than has been possible thus far. Genome information for Synechocystis sp. PCC 6714 has been deposited in Genbank (accession no AMZV01000000).