The BCCM/ULC collection: a Biological Ressource Center to give access to the Antarctic cyanobacterial diversity

anglais. On the Antarctic continent, Cyanobacteria represent the key primary producers and the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They may present interesting features to survive freeze/thaw cycles, sea-sonally contrasted light intensities, high UV radiations, dessication and other stresses. The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.). It makes it available for researchers to study the taxonomy, evolu-tion, adaptations to harsh environmental conditions, and genomic make-up. It pres-ently includes 226 cyanobacterial strains, with 119 being of Antarctic origin (cata-logue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The morphological identification shows that the strains belong to the orders Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. We present here the molecular datasets showing the diversity of the BCCM/ULC strains, studied on the basis of the 16S rRNA gene. A selection of strains was also characterized by sequencing of rpoC1, recA, and gyrA genes after amplification with newly designed primers. Our results mainly show that 25 OTUs included strains of Antarctic origin. Moreo-ver, strains identified as members of the genera Leptolyngbya or Phormidium ap-pear in several lineages. This supports the need to revise these polyphyletic genera with a simple filamentous morphology. A certain divergence of some Antarctic strains from related strains isolated from other regions can also be observed. It suggests that a portion of the Antarctic cyanobacterial flora may have evolved in-dependently from the cyanobacteria in other continents.

BCCM/ULC collection of cyanobacteria