New freshwater Bathycoccaceae lineage from Argentinean Patagonia shows distance related population structure

LARA, E.; FERNANDEZ PARRA, L.; SCHIAFFINO, M. R.; IZAGUIRRE I.

Granada

Congreso; 2015 Aquatic Sciences Meeting ASLO; 2015

ASLO

We detected by molecular fingerprinting the presence of the first freshwater member ever reported of the family Bathycoccaceae in a latitudinal gradient of lakes situated in Southern Argentina Patagonia. A fragment comprising the SSU rRNA gene + ITS region was cloned from environmental DNA using specific mamiellophyte primers. The unique SSU rRNA gene sequence obtained clustered robustly with Bathycoccus prasinos, a marine picoalga of considerable importance in planktonic ecosystems. Analysis of the ITS region showed the presence of a typical ITS2-Helix 3 in the ITS-2 region, a synapomorphy of Bathycoccaceae. In order to test whether there are biogeographic patterns that influence community composition, we compared ITS regions obtained from clones from the six different lakes to infer intra-specific diversity. No surveyed environmental parameter appeared to be correlated to haplotype composition. In contrast, we demonstrated that, in opposition to what has been observed in marine Bathycoccaceae, community composition is significantly influenced by geographic distance and by the presence of natural barriers between the lakes. We conclude therefore that geographical isolation is probably a cause for genetic differentiation in freshwater Bathycoccaceae.