Characterization of two Synechococcus sp. PCC7002‐related cyanobacterial strains in relation to 16S rDNA,crtR gene,lipids and pigments

Two Synechococcus strains from the Culture Collection of the Institute for Marine Sciences of Andalusia (Cádiz, Spain), namely Syn01 and Syn02, were found to be closely related to the model strain Synechococcus sp. PCC7002 according to 16S rDNA (99% identity). Pigment and lipid profiles and crtR genes of these strains were ascertained and compared. The sequences of the crtR genes of these strains were constituted by 888 bp, and showed 99% identity between Syn01 and Syn02, and 94% identity of Syn01 and Syn02 to Synechococcus sp. PCC7002. There was coincidence in photosynthetic pigments between the three strains apart from the pigment synechoxanthin, which could be only observed in Synechococcus sp. PCC7002. Species of sulfoquinovosyl‐diacyl‐glycerol (SQDG), phosphatidyl‐glycerol (PG), mono‐ and di‐galactosyl‐diacyl‐glycerol (MGDG and DGDG) were detected by high performance liquid chromatography‐mass spectrometry analysis of lipid extracts. The most abundant species within each lipid class were those containing C18:3 together with C16:0 fatty acyl substituents in the glycerol backbone of the same molecule. From these results it is concluded that these cyanobacterial strains belong to group 2 of the lipid classification of cyanobacteria.