Roncero-Ramos Beatriz, Muñoz-Martín M Ángeles, Chamizo Sonia, Fernández-Valbuena Lara, Mendoza Diego, Perona Elvira, Cantón Yolanda, Mateo Pilar
Departamento de Agronomía, Universidad de Almería, Almería, Spain.
Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain.
PeerJ. 2019 Jan 3;7:e6169. doi: 10.7717/peerj.6169. eCollection 2019.
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 (, , and ), which play an important role in N and C cycling in soil; nonheterocystous bundle-forming cyanobacteria (, , and cf); and narrow filamentous cyanobacteria ( and ), 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.
蓝细菌是表土群落中的关键微生物，在防止土壤侵蚀、碳氮固定以及影响土壤水文方面发挥着重要作用。然而，对于在欧洲旱地形成具有凝聚力的生物土壤结皮（生物结皮）的光合组合中微生物成分的身份和分布，我们知之甚少。在本研究中，我们调查了来自欧洲最干旱地区（西班牙东南部）三个具有代表性的旱地生态系统中定殖于生物结皮的蓝细菌物种，这些生态系统具有不同的土壤条件。通过多相方法对分离出的蓝细菌培养物进行鉴定，包括16S rRNA基因测序、系统发育关系确定以及形态和生态栖息地评估。鉴定出三个明显不同的类群：异形胞蓝细菌（、、和），它们在土壤氮和碳循环中起重要作用；非异形胞束状蓝细菌（、、和cf）；以及窄丝状蓝细菌（和），所有这些都是生物结皮初始形成的重要属。本研究结果有助于我们了解来自欧洲重要但研究不足的栖息地（如地中海盆地，生物多样性热点地区，这些物种是关键先锋生物）的生物结皮中的蓝细菌物种组成。
