Résumé
Cyanobacterial blooms have become ail increasing worldwide problem in aquatic habitats. Certain species of cyanobacteria produce toxins of several types that threaten the health of animals and humans and may affect tourism and recreation activities. Therefore, early identification and prediction of such toxic blooms arc, essential for proper management of the aquatic environment. Here we report on the development and application of a molecular diagnostic tool for rapid identification of potentially toxic cyanobacteria. Toxic cyanobacteria species, Aphanizomenon ovalisporum and two Microcystis strains, were isolated front Lake Kinneret (Sea of Galilee, Israel), and a large DNA fragment of the rDNA gene was cloned and sequenced for these species. Restriction enzymes were selected according to the sequences to yield species-specific fragment patterns. A set of primers was designed to amplify the 16S-ITS1-23S region, which wits then digested by the selected restriction enzymes to yield known fragment patterns. This Amplified Ribosomal DNA Restriction Analysis (ARDRA) was applied to identify toxic cyanobacteria as an experimental approach within it survey program operated in the Lake Kinneret catchments area aimed to assess the presence of cyanobacteria that may invade the take ecosystem. The ARDRA results indicated that the reconstructed wetland area in the Hula valley (also known as Agmon). located upstream from Lake Kinneret. was populated by Microcystis species during the survey period. These results were further confirmed by microscopic observations.