The Roscoff Culture Collection (RCC): a collection dedicated to marine picoplankton
Vaulot, Daniel; Gall, Florence; Le Marie, Dominique; Guillou, Laure; Partensky, Frédéric
The Roscoff Culture Collection (RCC, http://www. sb-roscoff. fr/Phyto/RCC/index. php) holds over 500 strains of marine cyanobacteria and microalgae with a strong emphasis on picoplankton, i. e. cells with size below 2-3 microns. Most of these strains have been obtained from the Equatorial Pacific, the Tropical Atlantic, the Mediterranean Sea, the Red Sea, the North Sea and the English Channel. A large fraction of strains are characterized based on ultrastructure features, pigment analyses and SSU rDNA sequencing. With respect to prokaryotes, the RCC holds more than 100 strains of Prochlorococcus and Synechococcus. Both genera exhibit considerable ecotypic variability since they colonize virtually all oceanic waters from tropical oligotrophic regions to temperate coastal areas. These two cyanobacteria should receive increasing attention with the recent availability of complete genome sequences of four representative isolates. In recent years, we have also isolated novel picoeukaryotic strains from several algal classes (Prasinophyceae, Prymnesiophyceae, Bolidophyceae, Dictyochophyceae, Pelagophyceae...). As an example, we have now 20 strains of Ostreococcus (Prasinophyceae, Mamiellales), the smallest photosynthetic eukaryote initially isolated from Thau lagoon in France. These Ostreococcus strains originate from environments as diverse as the Red Sea or the coast of Brittany. We are currently extending our collection to heterotrophic picoplankton, since this compartment is probably very diversified, as revealed by recent molecular studies.