Cyanobacteria are oxygenic photosynthetic prokaryotes that contribute largely to the balance between CO2and O2in the atmosphere. Adapted to a wide range of environmental conditions, they colonize most ecosystems. In continental and marine water bodies, the abundance of bloom-forming representatives disrupts the equilibrium of these environments, and the potentially associated cyanotoxins may be harmful to animals and Man.

Created in July 2009, the Collection of Cyanobacteria houses the Pasteur Culture Collection of Cyanobacteria (PCC) and continues its different service activities (acquisition and preservation of the organisms; sales of strains and consultation). This biological resource is also the base of our main research programs, one on the biodiversity of cyanobacteria, the other on the diversity of secondary metabolites, particularly cyanotoxins, produced by these microorganisms.

Biodiversity of cyanobacteria. The cyanobacterial collection of the PCC comprises more than 750 axenic strains isolated from very diverse habitats. The sequencing of the 16S rDNA of the majority of the PCC strains (Coll. Génoscope, Evry) permitted to select reference strains for several on-going genomic projects in which the Collection of Cyanobacteria is actively involved to investigate the diversity and evolution of cyanobacteria at phylum, family and species levels (collaborations with Genoscope, Evry; DOE-JGI, Berkeley, California; University of Düsseldorf, Germany; Penn State University, Pennsylvania).

CyanobacterialNRPS/PKS metabolites. Cyanobacteria produce a large variety of bioactive compounds, some of which are toxic. Several funded projects permitted to focus on the most commonly occurring cyanobacterial hepatotoxin producers, such as MicrocystisPCC 7806 (Cadel-Six et al., 2008; Frangeul et al., 2009; Straub et al., 2010 In press), and on neurotoxic filamentous cyanobacteria with the strain OscillatoriaPCC 6506 (Cadel-Six et al., 2009). We have extended these investigations to a larger scale covering the on-going PCC strains genomes as well as new isolates from tropical marine environments. The ensemble of our studies should permit to get deeper insights into the diversity and evolution of these non-ribosomal metabolites (collaborations with ANR CES ARISTOCYA; Genoscope, Evry; University of Helsinki; University of Bonn).

Keywords: Cyanobacteria, biodiversity, evolution, cyanotoxins, NRPS PKS metabolites

Humbert, J.-F., C. Quiblier, and M. Gugger. 2010. Molecular approaches for monitoring potentially toxic marine and freshwater phytoplankton species. Analytical and Bioanalytical Chemistry 397:1723-1732. PMID: 20333361

Straub, C., P. Quillardet, J. Vergalli, N. Tandeau de Marsac, and J.-F. Humbert. 2010. A day in the life of Microcystis aeruginosa PCC 7806 as revealed by a transcriptomic approach. PLoS One. In press

Janssen, P., N. Morin, M. Mergeay, B. Leroy, R. Wattiez, T. Vallaeys, K. Waleron, A. Wilmotte, P. Quillardet, N. Tandeau de Marsac, E. Talla, C. Zhang, and N. Leys. 2010. Genome sequence of the edible cyanobacterium Arthrospira PCC 8005. Journal of Bacteriology 192:2465-2466. PMID: 20233937

Cadel-Six S., Iteman I., Peyraud-Thomas C., Mann S., Ploux O., Méjean A. 2009.Identification of a polyketide synthetase coding sequence specific for anatoxin-a producing OscillatoriaCyanobacteria.Appl. Environ. Microbiol. 75, 4909-4912. PMID: 19447947.

Briand, E., N. Escoffier, C. Straub, M. Sabart, C. Quiblier, and J.-F. Humbert. 2009. Spatiotemporal changes in the genetic diversity of a bloom-forming Microcystis aeruginosa (cyanobacteria) population. The ISME Journal 3:419-429. PMID: 19092863