Biodiversity of freshwater microalgae: germplasm bank and obtaining of molecular markers of cryopreserved species

Abstract

The purpose of the project is to begin a germplasm bank, cryopreserved in liquid nitrogen, of freshwater microalgae (phytoplanktonic, but also thycoplanktonic, benthic and sub-aerial which may be cultivated and frozen), in order to maintain the biodiversity of these organisms, along with a database of information on the species. The first step to achieve this intent is to isolate clones throughout the UGRHI from the State of Sao Paulo, including previously demarcated stations by the Biota Program, cultivate them and insert them in the collection of metabolically active culture of the Collection of Freshwater Microalgae Cultures of UFSCar. Immediately after isolation, we will develop freezing protocols aiming the progressive transfer of such cultures to the frozen "bank" (cryopreservation).The studies of DNA barcode will begin with Chlorophyceae, but later expanding to other groups of which DNA barcodes are already being obtained more routinely, such as diatoms and dinoflagellates. For this, the organisms will be previously identified by traditional taxonomy. Although the "DNA barcoding" is already being successfully applied for several groups of non-green algae, it does not happen with the green algae or 'higher' plants, which requires further research. We believe that this theme is also proper to begin studies for prospecting of metabolic specific molecules that may be applied as biomarkers and, therefore, interesting for the taxonomic characterization of the species to be frozen. The approach of biomarkers will start with the profiles of fatty acids and extracellular polysaccharides (monomer composition and some physical properties), which have the potential to be useful to delimit higher taxa, like orders and genera, and even species, according with literature. We will also begin, in a later stage of the project, the novel experimental approach of comparative analysis by electronic sensors of the profile of released compounds by the species as biomarkers. Besides the taxonomic utility, biomarkers yield important information on the economic point of view, which enriches the information bank of the frozen collection. The expected results are: the substantial increase in collection of metabolically active cultures, which will be gradually transferred to the collection of cryopreserved species; the availability of frozen clones along with important information about the species; the transfer of the DNA-barcode results for the BOLD, COBOL and GenBank data systems; and the creation of a database with information not only on the sequences and primers, but also about the environment, as physical and chemical characteristics of water. The list of the frozen/active collections will be inserted to the project Biota database. (AU)