MODENUTTI Beatriz Estela
congresos y reuniones científicas
DIVERSITY OF THE ITS-1 OPERON AND PHOTOSYNTHETIC TRAITS OF ANDEAN FRESHWATER PICOCYANOBACTERIA
CRISTIANA CALLIERI; CARAVATI, E.; MODENUTTI, B.; C. CORNO; BALSEIRO, E.; ROBERTO BERTONI; MICHAUD L.
Congreso; ASLO Annual Meeting 2009; 2009
In ultraoligotrophic North Patagonian Andean lakes picocyanobacteria (Pcy) are the dominant picophytoplankters comprising 50% of the total primary production and 30% of autotrophic biomass, as average in the water column. Automated rRNA Intergenic Spacer Analysis (ARISA) was used to study the structure and the diversity of Pcy community in six of these lakes. We investigated the relationships among the Operational Taxonomic Units (OTUs) and the photosynthetic characteristics of Pcy assemblages. The six lakes clustered into two main groups mirroring their history after the Last Glacial Maximum. About 50% of significant ARISA fragments appeared to be site specific, others displayed cosmopolitan distribution. The relative DNA fluorescence of one OTU was significantly related to chlorophyll specific production. The variation of the photosynthetic traits of the two clusters characterized by different OTU diversity is consistent with the hypothesis that the ITS-1 sequence of Pcy define functionally differentiated groups. Clone libraries approach coupled with ITS-1 analyses was used to obtain phylogenetic information of ARISA fragments and an ITS-1 phylogenetic tree was inferred using marine and freshwater picocyanobacteria published sequences.