Soares Fabiana, Trovão João, Ahn Anne-Catherine, Wilmotte Annick, Cardoso Susana M, Tiago Igor, Portugal António
Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, 3000-456, Portugal.
BCCM/ULC Culture Collection, InBios-Centre for Protein Engineering, University of Liège, Liège, B-4000, Belgium.
J Phycol. 2022 Apr;58(2):219-233. doi: 10.1111/jpy.13241. Epub 2022 Mar 5.
The Synechococcales is a large cyanobacterial order comprising both unicellular and filamentous forms, with parietal thylakoid arrangement. Previously, this order has been the subject of taxonomic revisions with new families being erected. During studies of the phototrophic communities on the limestone walls of the Old Cathedral of Coimbra (UNESCO monument), a coccoid Aphanocapsa-like cyanobacterium was isolated. It was characterized using a polyphasic approach, based on morphology, 16S rRNA phylogenetic and phylogenomic analyses, internal transcribed spacer (ITS) secondary structure, and ecology. The 16S rRNA phylogenetic analyses showed that this strain is placed in a separate and highly supported family-level clade, as part of a large group comprising the families Prochlorococcaceae and Prochlorotrichaceae, with Lagosinema as the closest (although quite distant) taxon. Additionally, the phylogenomic analysis also placed this strain in a separate lineage, situated distantly apart from the family Thermosynechococcaceae, but with strains assigned to Acaryochloris marina MBIC 11017 and Aphanocapsa montana BDHKU210001 as the closest taxa. Based on these data, as well as on the results from the secondary ITS structure, morphology, and ecology, we here propose the establishment of Petrachlorosaceae fam. nov., along with the description of Petrachloros gen. nov. and Petrachloros mirabilis sp. nov. We also address additional considerations regarding some cyanobacterial taxa within the order Synechococcales, which we believe deserve further revisions.
聚球藻目是一个大型的蓝细菌目，包括单细胞和丝状形态，类囊体排列在周质。此前，这个目一直是分类修订的对象，新的科不断被建立。在对科英布拉老教堂（联合国教科文组织古迹）石灰岩墙壁上的光合生物群落进行研究时，分离出一种类隐球藻属的球状蓝细菌。基于形态学、16S rRNA系统发育和系统基因组分析、内部转录间隔区（ITS）二级结构以及生态学，采用多相方法对其进行了表征。16S rRNA系统发育分析表明，该菌株位于一个单独的、得到高度支持的科级分支中，是包括原绿球藻科和原绿丝藻科在内的一个大群体的一部分，拉戈丝藻属是最接近的（尽管相距较远）分类单元。此外，系统基因组分析也将该菌株置于一个单独的谱系中，与嗜热聚球藻科相距甚远，但与被归入滨海无叶绿素蓝细菌MBIC 11017和蒙塔纳隐球藻BDHKU210001的菌株最为接近。基于这些数据，以及ITS二级结构、形态学和生态学的结果，我们在此提议建立新科彼得拉绿藻科，同时描述新属彼得拉绿藻属和新种奇异彼得拉绿藻。我们还讨论了关于聚球藻目内一些蓝细菌分类单元的其他考虑因素，我们认为这些因素值得进一步修订。
