Comparative genome analysis of the closely related Synechocystis strains PCC 6714 and PCC 6803.
Bottom Line: PCC 6714.Genome information for Synechocystis sp.PCC 6714 has been deposited in Genbank (accession no AMZV01000000).
Affiliation: Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany.Show MeSH
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Mentions: The higher number of transposon genes in Synechocystis 6803 is correlated with a low degree of syntheny between the two strains. Another situation exists with the rfb-gene cluster that differs entirely between the two strains and encodes several glycosyltransferases possibly involved in cell wall biosynthesis and the modification of cell surface properties. This region has features of a genomic island, since the adjacent genes are conserved between the two Synechocystis strains, but the GC content drops considerably (from 48 to 35%) within this region in both strains (Fig. 2). Genomic islands consist of sets of genes that become laterally transferred, belong to the flexible gene pool of a bacterial phylum and frequently provide a certain fitness advantage.30 Accordingly, the most closely related homologues matching to these proteins are found in a wide variety of organisms. For the 50 genes located in the Synechocystis 6714 rfb gene cluster, the phylogenetically top-matching proteins belong to groups as diverse as Zetaproteobacteria, Bacilli, Clostridia, Armatimonadetes, Rhodopirellula, and Stigonematales cyanobacteria. The top-matching proteins against the Synechocystis 6803 rfb gene cluster proteins are of comparable diversity. A particular example is also the norf2 gene which was annotated on the basis of transcriptome data.19 The most closely related proteins to Norf2 (Fig. 2) are annotated in Thiocapsa marina (69% identical and 86% similar residues) and several Thioalkalivibrio species, pointing further to the alien origin of this genomic region.Figure 2.
Affiliation: Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany.