Abstract

The diatom Didymosphenia geminata (DG) is an invasive unicellular alga from benthic freshwater environments. This alga is capable of produce massive algal blooms, causing serious consequences of ecological, economic and aesthetic nature. In 2004 DG was reported for the first time in the southern hemisphere, affecting New Zealand and quickly spread all along the south island. In 2010 this microalga was detected for the first time in south America, in the Futaleufú river watershed (Los Lagos Region, Chile), and in 2013 was reported its presence in the Magellan region (subantarctic region), invading gradually the Blanco lake, Blanco, Grande and Serrano rivers, the latter located in the Torres del Paine National Park. So far, the identification of DG in Magellan region was performed using taxonomic classification and the geographical origin of the microalgae has not been elucidated yet, thus we performed genetic analysis to clarify its origin. Five samples from each of four water reservoirs (river or lake), where obtained to collect cells of DG. Because the complex diversity of microorganisms present in the samples, a filtration and purification protocol was developed to isolate DG from other microalgae. Subsequently, DNA extraction protocol based on the CTAB method was standardized. Genetic analysis using specific primers to amplify a fragment of the mitochondrial gene 18S of DG was performed. Our results showed the genetic identification of DG in 3 freshwater courses of the Magellan region. This study set the methodological basis for future genetic and genomic analysis of this species.