Figure 1

Phylogenetic tree of photosynthetic bacteria. The tree was constructed using the phylogenetic software MEGA4.1 with un-rooted neighbor joining 16S rRNA dendrogram from five phyla of photosynthetic microbes, including cyanobacteria, heliobacteria, purple bacteria, green sulfur bacteria and filamentous anoxygenic phototrophs (FAPs) (each phylum of bacteria highlighted in different color). Bacterial names and accession numbers of 16S rRNA genes are listed as follows: (1) purple bacteria: Roseobacter denitrificans OCh114 (CP000362), Roseobacter litoralis (X78312), Rhodobacter capsulatus (D16428), Rhodobacter sphaeroides 2.4.1 (X53853), Rhodopseudomonas faecalis strain gc (AF123085), Rhodopseudomonas palustris (D25312), Rhodopseudomonas acidophila (FR733696), Rhodopseudomonas viridis DSM 133 (AF084495), Rubrivivax gelatinosus (D16213); (2) heliobacteria: Heliobacterium gestii (AB100837), Heliobacterium modesticaldum (CP000930); (3) cyanobacteria: Oscillatoria amphigranulata strain 19-2 (AF317504), Oscillatoria amphigranulata strain 11-3 (AF317503), Oscillatoria amphigranulata strain 23-3 (AF317505), Microcystis aeruginosa NIES-843 (AP009552), Nostoc azollae 0708 (NC_014248); (4) green sulfur bacteria: Chlorobaculum thiosulfatiphilum DSM 249 (Y08102), Pelodictyon luteolum DSM 273 (CP000096), Chlorobium limicola DSM 245 (CP001097), Chlorobaculum tepidum TLS (M58468), Chlorobium vibrioforme DSM 260 (M62791); and (5) FAPs: Chloroflexus aurantiacus J-10-fl (M34116), Chloroflexus aggregans (D32255), Oscillochloris trichoides (AF093427), Roseiflexus castenholzii DSM 13941 (AB041226). Archaea (Archaeoglobus profundus DSM 5631 (NC_013741) and Methanocaldococcus jannaschii DSM 2661 (NC_000909)) were used as an out-group.