Cyanobacteria are a key 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 the composition and diversity of cyanobacteria associated with 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. Nine different morphotypes were observed, eight corresponding to filamentous, and one to unicellular cyanobacteria. We found cyanobacterial genera typical of biocrust communities, such as Microcoleus and Trichocoleus, and N-fixing cyanobacteria such as Scytonema and Nostoc. Genetic information allowed us to identify cultures belonging to recently described genera such as Roholtiella, Nodosilinea and Mojavia. We also describe two new phylotypes of Microcoleus and Scytonema, which are key genera contributing to ecosystem functioning in biocrust-dominated ecosystems worldwide.

中文翻译：

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西班牙中部半干旱吉普赛地区形成生物结壳的蓝细菌的多样性

蓝藻是生物结皮的关键组成部分，是由地衣、苔藓和相关微生物主导的群落，它们在世界各地的旱地中普遍存在，并在很大程度上决定了它们的功能。尽管它们很重要，但我们对与生物结皮相关的蓝藻的组成和多样性的认识仍然存在很大差距，特别是在地中海盆地等地区。我们使用培养后的形态学鉴定和 16S rRNA 基因的遗传分析研究了这些蓝藻在西班牙中部的石膏草草地中的多样性。观察到九种不同的形态类型，八种对应于丝状，一种对应于单细胞蓝藻。我们发现了典型的生物结皮群落的蓝藻属，例如 Microcoleus 和 Trichocoleus，和固氮蓝细菌，如 Scytonema 和 Nostoc。遗传信息使我们能够识别属于最近描述的属的文化，例如 Roholtiella、Nodosilinea 和 Mojavia。我们还描述了 Microcoleus 和 Scytonema 的两种新系统型，它们是在全球以生物结皮为主的生态系统中促进生态系统功能的关键属。