Abstract
Cyanobacteria are an important constituent of biocrusts, communities dominated by lichens, mosses and associated microorganisms, which are prevalent in drylands worldwide and that largely determine their functioning. Despite their importance, there are large gaps in our knowledge of cyanobacteria associated to biocrusts, particularly in areas such as the Mediterranean Basin. We studied the diversity of these cyanobacteria in a gypsiferous grassland from Central Spain using both morphological identification after cultivation and genetic analyses with the 16S rRNA gene. Eight different morphotypes were observed, most of them corresponding to filamentous and one of them to unicellular cyanobacteria. We found cyanobacterial genera typical of biocrust communities, such as Microcoleus, Schizothrix or Tolypothrix, and N-fixing cyanobacteria as Scytonema or Nostoc. Genetic information allowed us to identify cultures belonging to recently described genera such as Roholtiella, Nodosilinea and Mojavia. In this study we describe two new phylotypes of Microcoleus and Scytonema, which are key genera contributing to ecosystem functioning in biocrust-dominated ecosystems worldwide.
