Unravelling the genomic mosaic of a ubiquitous genus of marine cyanobacteria

@article{citeulike:2841303, abstract = {BACKGROUND:The picocyanobacterial genus Synechococcus occurs over wide oceanic expanses, having colonized most available niches in the photic zone. Large scale distribution patterns of the different Synechococcus clades (based on 16S rRNA gene markers) suggest the occurrence of two major lifestyles ('opportunists'/'specialists'), corresponding to two distinct broad habitats ('coastal'/'open ocean'). Yet, the genetic basis of niche partitioning is still poorly understood in this ecologically important group.RESULTS:Here, we compare the genomes of 11 marine Synechococcus isolates, representing 10 distinct lineages. Phylogenies inferred from the core genome allowed us to refine the taxonomic relationships between clades by revealing a clear dichotomy within the main subcluster, reminiscent of the two aforementioned lifestyles. Genome size is strongly correlated with the cumulative lengths of hypervariable regions (or 'islands'). One of these, encompassing most genes encoding the light-harvesting phycobilisome rod complexes, is involved in adaptation to changes in light quality and has clearly been transferred between members of different Synechococcus lineages. Furthermore, we observed that two strains (RS9917 and WH5701) which have similar pigmentation and physiology, have an unusually high number of genes in common, given their phylogenetic distance.CONCLUSIONS:We propose that while members of a given marine Synechococcus lineage may have the same broad geographical distribution, local niche occupancy is facilitated by lateral gene transfers, a process in which genomic islands play a key role as a repository for transferred genes. Our work also highlights the need for developing picocyanobacterial systematics based on genome-derived parameters combined with ecological and physiological data.}, author = {Dufresne, Alexis and Ostrowski, Martin and Scanlan, David and Garczarek, Laurence and Mazard, Sophie and Palenik, Brian and Paulsen, Ian and de Marsac, Nicole T. and Wincker, Patrick and Dossat, Carole and Ferriera, Steve and Johnson, Justin and Post, Anton and Hess, Wolfgang and Partensky, Frederic }, citeulike-article-id = {2841303}, doi = {10.1186/gb-2008-9-5-r90}, journal = {Genome Biology}, number = {5}, posted-at = {2008-06-05 17:53:29}, priority = {2}, title = {Unravelling the genomic mosaic of a ubiquitous genus of marine cyanobacteria}, url = {http://dx.doi.org/10.1186/gb-2008-9-5-r90}, volume = {9}, year = {2008} }

TY - JOUR ID - citeulike:2841303 L3 - citeulike-article-id:2841303 TI - Unravelling the genomic mosaic of a ubiquitous genus of marine cyanobacteria JF - Genome Biology VL - 9 IS - 5 N2 - BACKGROUND:The picocyanobacterial genus Synechococcus occurs over wide oceanic expanses, having colonized most available niches in the photic zone. Large scale distribution patterns of the different Synechococcus clades (based on 16S rRNA gene markers) suggest the occurrence of two major lifestyles ('opportunists'/'specialists'), corresponding to two distinct broad habitats ('coastal'/'open ocean'). Yet, the genetic basis of niche partitioning is still poorly understood in this ecologically important group.RESULTS:Here, we compare the genomes of 11 marine Synechococcus isolates, representing 10 distinct lineages. Phylogenies inferred from the core genome allowed us to refine the taxonomic relationships between clades by revealing a clear dichotomy within the main subcluster, reminiscent of the two aforementioned lifestyles. Genome size is strongly correlated with the cumulative lengths of hypervariable regions (or 'islands'). One of these, encompassing most genes encoding the light-harvesting phycobilisome rod complexes, is involved in adaptation to changes in light quality and has clearly been transferred between members of different Synechococcus lineages. Furthermore, we observed that two strains (RS9917 and WH5701) which have similar pigmentation and physiology, have an unusually high number of genes in common, given their phylogenetic distance.CONCLUSIONS:We propose that while members of a given marine Synechococcus lineage may have the same broad geographical distribution, local niche occupancy is facilitated by lateral gene transfers, a process in which genomic islands play a key role as a repository for transferred genes. Our work also highlights the need for developing picocyanobacterial systematics based on genome-derived parameters combined with ecological and physiological data. AU - Dufresne, Alexis AU - Ostrowski, Martin AU - Scanlan, David AU - Garczarek, Laurence AU - Mazard, Sophie AU - Palenik, Brian AU - Paulsen, Ian AU - de Marsac, Nicole AU - Wincker, Patrick AU - Dossat, Carole AU - Ferriera, Steve AU - Johnson, Justin AU - Post, Anton AU - Hess, Wolfgang AU - Partensky, Frederic PY - 2008/// UR - http://dx.doi.org/10.1186/gb-2008-9-5-r90 ER -