Suchergebnisse

Cyanobacteria are key microbes in topsoil communities that have important roles in preventing soil erosion, carbon and nitrogen fixation, and influencing soil hydrology. However, little is known regarding the identity and distribution of the microbial components in the photosynthetic assemblages that form a cohesive biological soil crust (biocrust) in drylands of Europe. In this study, we investigated the cyanobacterial species colonizing biocrusts in three representative dryland ecosystems from the most arid region in Europe (SE Spain) that are characterized by different soil conditions. Isolated cyanobacterial cultures were identified by a polyphasic approach, including 16S rRNA gene sequencing, phylogenetic relationship determination, and morphological and ecological habitat assessments. Three well-differentiated groups were identified: heterocystous-cyanobacteria (Nostoc commune, Nostoc calcicola, Tolypothrix distorta and Scytonema hyalinum), which play an important role in N and C cycling in soil; nonheterocystous bundle-forming cyanobacteria (Microcoleus steenstrupii, Trichocoleus desertorum, and Schizothrix cf. Calcicola); and narrow filamentous cyanobacteria (Leptolyngbya frigida and Oculatella kazantipica), all of which are essential genera for initial biocrust formation. The results of this study contribute to our understanding of cyanobacterial species composition in biocrusts from important and understudied European habitats, such as the Mediterranean Basin, a hotspot of biodiversity, where these species are keystone pioneer organisms ; This research was supported by grants from the Spanish Government and European Regional Funds (CGL2013-44870-R, CGL2014-59946-R and CGL2017-86258-R). The study has also received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 706351, Project Cyano4REST. B.R-R. was supported by a predoctoral fellowship from the foundation Tatiana Pérez de Guzmán el Bueno. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript