Jung Patrick, Brust Katharina, Schultz Matthias, Büdel Burkhard, Donner Antje, Lakatos Michael
Department of Integrative Biotechnology, University of Applied Sciences Kaiserslautern, Pirmasens, Germany.
Ecology Group, Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany.
Front Microbiol. 2021 Oct 6;12:728378. doi: 10.3389/fmicb.2021.728378. eCollection 2021.
The last decades of research led to a change in understanding of lichens that are now seen as self-sustaining micro-ecosystems, harboring diverse microbial organisms in tight but yet not fully understood relationships. Among the diverse interdependencies, the relationship between the myco- and photobiont is the most crucial, determining the shape, and ecophysiological properties of the symbiotic consortium. Roughly 10% of lichens associate with cyanobacteria as their primary photobiont, termed cyanolichens. Up to now, the diversity of cyanobionts of bipartite lichens resolved by modern phylogenetic approaches is restricted to the filamentous and heterocytous genera of the order Nostocales. Unicellular photobionts were placed in the orders Chroococcales, Pleurocapsales, and Chroococcidiopsidales. However, especially the phylogeny and taxonomy of the Chroococcidiopsidales genera remained rather unclear. Here we present new data on the identity and phylogeny of photobionts from cyanolichens of the genera , , , and from a broad geographical range. A polyphasic approach was used, combining morphological and cultivation-depending characteristics (microscopy, staining techniques, life cycle observation, baeocyte motility, and nitrogen fixation test) with phylogenetic analyses of the 16S rRNA and 16S-23S ITS gene region. We found an unexpectedly high cyanobiont diversity in the cyanobacterial lichens of the order Lichinales, including two new genera and seven new species, all of which were not previously perceived as lichen symbionts. As a result, we describe the novel unicellular Chroococcidiopsidales genera gen. nov. with the species sp. nov. (from , Australia) and gen. nov. with the species sp. nov. (from sp., Australia) and the new Chroococcidiopsidales species sp. nov. (from , Australia), sp. nov. (from ; South Africa), sp. nov. (from , Austria), as well as the two new Nostocales species sp. nov. (from sp., Czechia) and sp. nov. (from , Canary Islands, Spain). Our study highlights the role of cyanolichens acting as a key in untangling cyanobacterial taxonomy and diversity. With this study, we hope to stimulate further research on photobionts, especially of rare cyanolichens.
过去几十年的研究使人们对 lichens 的理解发生了变化，现在它们被视为自我维持的微生态系统，其中包含各种微生物，它们之间的关系紧密但尚未完全明了。在各种相互依存关系中，真菌共生体和光合共生体之间的关系最为关键，它决定了共生联合体的形态和生态生理特性。大约 10% 的 lichens 与蓝细菌作为其主要光合共生体相关联，称为蓝藻地衣。到目前为止，通过现代系统发育方法解析的二分地衣蓝藻共生体的多样性仅限于念珠藻目的丝状和异形胞属。单细胞光合共生体被归入色球藻目、侧孢藻目和球囊藻目。然而，特别是球囊藻目各属的系统发育和分类仍然相当不清楚。在这里，我们展示了来自广泛地理区域的、、、和属蓝藻地衣光合共生体的身份和系统发育的新数据。我们采用了多相方法，将形态学和依赖培养的特征（显微镜检查、染色技术、生命周期观察、藻胞运动性和固氮测试）与 16S rRNA 和 16S - 23S ITS 基因区域的系统发育分析相结合。我们在石耳目蓝藻地衣中发现了出乎意料的高蓝藻共生体多样性，包括两个新属和七个新物种，所有这些以前都未被视为地衣共生体。因此，我们描述了新的单细胞球囊藻目属，其物种为 sp. nov.（来自澳大利亚）和属，其物种为 sp. nov.（来自澳大利亚 sp.）以及新的球囊藻目物种 sp. nov.（来自澳大利亚）、sp. nov.（来自；南非）、sp. nov.（来自奥地利），以及两个新的念珠藻目物种 sp. nov.（来自捷克 sp.）和 sp. nov.（来自西班牙加那利群岛）。我们的研究突出了蓝藻地衣在解开蓝细菌分类学和多样性方面的关键作用。通过这项研究，我们希望激发对光合共生体，特别是对稀有蓝藻地衣的进一步研究。
