title: Diversity and phylogeny of Baltic Sea picocyanobacteria inferred from their ITS and phycobiliprotein operons.
abstract: Picocyanobacteria of the genus Synechococcus span a range of different colours, from red strains rich in phycoerythrin (PE) to green strains rich in phycocyanin (PC). Here, we show that coexistence of red and green picocyanobacteria in the Baltic Sea is widespread. The diversity and phylogeny of red and green picocyanobacteria was analysed using three different genes: 16S rRNA-ITS, the cpeBA operon of the red PE pigment and the cpcBA operon of the green PC pigment. Sequencing of 209 clones showed that Baltic Sea picocyanobacteria exhibit high levels of microdiversity. The partial nucleotide sequences of the cpcBA and cpeBA operons from the clone libraries of the Baltic Sea revealed two distinct phylogenetic clades: one clade containing mainly sequences from cultured PC-rich picocyanobacteria, while the other contains only sequences from cultivated PE-rich strains. A third clade of phycourobilin (PUB) containing strains of PE-rich Synechococcus spp. did not contain sequences from the Baltic Sea clone libraries. These findings differ from previously published phylogenies based on 16S rRNA gene analysis. Our data suggest that, in terms of their pigmentation, Synechococcus spp. represent three different lineages occupying different ecological niches in the underwater light spectrum. Strains from different lineages can coexist in light environments that overlap with their light absorption spectra.
authors: Department of Marine Microbiology, Netherlands Institute of Ecology, NIOO-KNAW, P.O. Box 140, 4400 AC Yerseke, The Netherlands.
authors: Thomas
authors: T
authors: Haverkamp
authors: Silvia G
authors: SG
authors: Acinas
authors: Marije
authors: M
authors: Doeleman
authors: Maayke
authors: M
authors: Stomp
authors: Jef
authors: J
authors: Huisman
authors: Lucas J
authors: LJ
authors: Stal
mesh_terms: D001483:Base Sequence; D044822:Biodiversity; D003062:Codon; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D017753:Ecosystem; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009792:Oceans and Seas; D009876:Operon; D052980:Phycobilins / Q000235:genetics; D052979:Phycobiliproteins / Q000235:genetics*; D010798:Phycocyanin / Q000235:genetics; D010799:Phycoerythrin / Q000235:genetics; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D046940:Synechococcus / Q000235:genetics*; D014557:Urobilin / Q000031:analogs & derivatives / Q000235:genetics
chemical_list: D003062:Codon; D021903:DNA, Ribosomal Spacer; D052980:Phycobilins; D052979:Phycobiliproteins; D012336:RNA, Ribosomal, 16S; D010798:Phycocyanin; D010799:Phycoerythrin; D014557:Urobilin; C044986:phycourobilin