Ma Guolin, Logares Ramiro, Xue Yuanyuan, Yang Jun
Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Ningbo Observation and Research Station, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China.
Front Microbiol. 2022 Sep 26;13:969799. doi: 10.3389/fmicb.2022.969799. eCollection 2022.
The cell size of microbial eukaryotic plankton normally ranges from 0.2 to 200 μm. During the past decade, high-throughput sequencing of DNA has been revolutionizing their study on an unprecedented scale. Nonetheless, it is currently unclear whether we can accurately, effectively, and quantitatively depict the microbial eukaryotic plankton community using size-fractionated filtration combined with environmental DNA (eDNA) molecular methods. Here we assessed the microbial eukaryotic plankton communities with two filtering strategies from two subtropical reservoirs, that is one-step filtration (0.2-200 μm) and size-fractionated filtration (0.2-3 and 3-200 μm). The difference of 18S rRNA gene copy abundance between the two filtering treatments was less than 50% of the 0.2-200 μm microbial eukaryotic community for 95% of the total samples. Although the microbial eukaryotic plankton communities within the 0.2-200 μm and the 0.2-3 and 3-200 μm size fractions had approximately identical 18S rRNA gene copies, there were significant differences in their community composition. Furthermore, our results demonstrate that the systemic bias introduced by size-fractionation filtration has more influence on unique OTUs than shared OTUs, and the significant differences in abundance between the two eukaryotic plankton communities largely occurred in low-abundance OTUs in specific seasons. This work provides new insights into the use of size-fractionation in molecular studies of microbial eukaryotes populating the plankton.
微生物真核浮游生物的细胞大小通常在0.2到200微米之间。在过去十年中，DNA高通量测序以前所未有的规模彻底改变了对它们的研究。然而，目前尚不清楚我们是否能够使用大小分级过滤结合环境DNA（eDNA）分子方法准确、有效且定量地描绘微生物真核浮游生物群落。在这里，我们通过两种过滤策略评估了来自两个亚热带水库的微生物真核浮游生物群落，即一步过滤（0.2 - 200微米）和大小分级过滤（0.2 - 3微米和3 - 200微米）。对于95%的总样本，两种过滤处理之间18S rRNA基因拷贝丰度的差异小于0.2 - 200微米微生物真核生物群落的50%。尽管0.2 - 200微米以及0.2 - 3微米和3 - 200微米大小分级内的微生物真核浮游生物群落具有大致相同的18S rRNA基因拷贝，但它们的群落组成存在显著差异。此外，我们的结果表明，大小分级过滤引入的系统偏差对独特的操作分类单元（OTU）的影响大于共享的OTU，并且两个真核浮游生物群落之间丰度的显著差异主要发生在特定季节的低丰度OTU中。这项工作为在浮游生物中微生物真核生物的分子研究中使用大小分级提供了新的见解。
