Zampieri Raffaella Margherita, Bizzotto Edoardo, Campanaro Stefano, Caldara Fabrizio, Bellucci Micol, La Rocca Nicoletta
Institute of Research on Terrestrial Ecosystems, National Research Council, Florence, Italy.
Department of Biology, University of Padua, Padua, Italy.
Front Microbiol. 2025 Mar 10;16:1545008. doi: 10.3389/fmicb.2025.1545008. eCollection 2025.
Hot springs are considered modern terrestrial environments analogous to Archean continental surfaces, where photosynthetic life could have evolved. In this habitat cyanobacteria dominate thanks to the adaptations to high temperature and the capability to acclimate to low light intensity and far-red enriched spectra typical of microbial biofilms. The isolation and characterization of new cyanobacterial species from these environments is fundamental to discover genetic and physiological traits allowing them to thrive under such unfavorable conditions, giving useful information to understand the evolution and plasticity of oxygenic photosynthesis as well as to assess their metabolic biodiversity for biotechnological purposes. In this study, we present the polyphasic characterization of a filamentous cyanobacterium, denominated strain ETS-13, isolated from mud biofilms collected in the Euganean Thermal District (Italy). The area is known since ancient times for the presence of thermal springs and muds exploited for the beneficial properties linked to heat, electrolytes, and organic compounds produced by the microbiota. The ETS-13 genome was assembled and annotated, while phylogenetic analyzes were performed using a combined approach based on the 16S rRNA sequence and considering the 16S-23S ITS secondary structures. In addition, morphological, biochemical, and physiological features of the organism were investigated, allowing its classification as a new species of the genus, named , which formed a cluster with other species of Leptolyngbyaceae from thermal environments. Interestingly, the strain was the first isolated in Italy capable of performing Far-Red Light Photoacclimation (FaRLiP) when exposed to far-red light, a feature found in other species of the same genus so far tested for this acclimation and isolated form geographically distant and different environments.
温泉被认为是类似于太古宙大陆表面的现代陆地环境，光合生命可能在此进化。在这个栖息地，蓝细菌占主导地位，这得益于它们对高温的适应能力以及适应低光照强度和微生物生物膜典型的富含远红光光谱的能力。从这些环境中分离和鉴定新的蓝细菌物种，对于发现使它们在如此不利条件下茁壮成长的遗传和生理特征至关重要，这为理解有氧光合作用的进化和可塑性以及评估它们用于生物技术目的的代谢生物多样性提供了有用信息。在本研究中，我们展示了一种丝状蓝细菌的多相特征，该菌株命名为ETS-13，是从意大利尤加尼安热区采集的泥质生物膜中分离出来的。自古以来，该地区就因温泉和泥浆的存在而闻名，这些温泉和泥浆因其与微生物群产生的热量、电解质和有机化合物相关的有益特性而被开发利用。我们对ETS-13的基因组进行了组装和注释，同时使用基于16S rRNA序列并考虑16S-23S ITS二级结构的组合方法进行了系统发育分析。此外，还研究了该生物体的形态、生化和生理特征，从而将其分类为一个新物种，命名为 ，它与来自热环境的其他细鞘丝藻科物种形成了一个聚类。有趣的是，该菌株是意大利首次分离出的在暴露于远红光时能够进行远红光光适应（FaRLiP）的菌株，这一特征在迄今为止针对这种光适应进行测试并从地理上遥远且不同的环境中分离出来的同一属的其他物种中也有发现。
