Molecular Data Reveal a Cryptic Diversity in the Genus Urotricha (Alveolata, Ciliophora, Prostomatida), a Key Player in Freshwater Lakes, With Remarks on Morphology, Food Preferences, and Distribution

作者：Daniela Frantal, Sabine Agatha, Daniela Beißer, Jens Boenigk, Tatyana Darienko, Gianna Dirren‐Pitsch, Sabine Filker, Michael Gruber, Barbara Kammerlander, Laura Nachbaur, Ulrike Scheffel, Thorsten Stoeck, Kuimei Qian, Birgit Weißenbacher, Thomas Pröschold, Bettina Sonntag · 发表于：Frontiers in Microbiology · 年份：2022 · DOI：10.3389/fmicb.2021.787290 · 被引用次数：28 · 研究领域：Protist diversity and phylogeny、Microbial Community Ecology and Physiology、Environmental DNA in Biodiversity Studies

Species of the ciliate genus Urotricha are key players in freshwater plankton communities. In the pelagial of lakes, about 20 urotrich species occur throughout an annual cycle, some of which play a pivotal role in aquatic food webs. For example, during the phytoplankton spring bloom, they consume a remarkable proportion of the algal production. In ecological studies, urotrich ciliates are usually merely identified to genus rank and grouped into size classes. This is unsatisfying considering the distinct autecological properties of individual species and their specific spatial and temporal distribution patterns. As a basis for future research, we characterized in detail four common urotrich morphotypes, i.e., specimens identified as U. furcata and tentatively as U. agilis , U. pseudofurcata , and U. castalia , using state-of-the-art methods. We used an integrative polyphasic approach, in which morphological studies ( in vivo observation, silver staining methods, scanning electron microscopy) were linked with a molecular approach exploiting four different gene fragments as taxonomic DNA barcodes with different resolution potential (SSU rDNA, ITS-1, ITS-2, hypervariable V4 and V9 regions of the SSU rDNA). We shed light on the diversity of urotrich ciliates as well as on their global distribution patterns, and annual cycles. Additionally, we coupled individual species occurrences and environmental parameters, and subsequently modeled the distribution and occurrence, using logisti...