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Useros F, García-Cunchillos I, Henry N, Berney C, Lara E. How good are global DNA-based environmental surveys for detecting all protist diversity? Arcellinida as an example of biased representation. Environ Microbiol 2024; 26:e16606. [PMID: 38509748 DOI: 10.1111/1462-2920.16606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 02/28/2024] [Indexed: 03/22/2024]
Abstract
Metabarcoding approaches targeting microeukaryotes have deeply changed our vision of protist environmental diversity. The public repository EukBank consists of 18S v4 metabarcodes from 12,672 samples worldwide. To estimate how far this database provides a reasonable overview of all eukaryotic diversity, we used Arcellinida (lobose testate amoebae) as a case study. We hypothesised that (1) this approach would allow the discovery of unexpected diversity, but also that (2) some groups would be underrepresented because of primer/sequencing biases. Most of the Arcellinida sequences appeared in freshwater and soil, but their abundance and diversity appeared underrepresented. Moreover, 84% of ASVs belonged to the suborder Phryganellina, a supposedly species-poor clade, whereas the best-documented suborder (Glutinoconcha, 600 described species) was only marginally represented. We explored some possible causes of these biases. Mismatches in the primer-binding site seem to play a minor role. Excessive length of the target region could explain some of these biases, but not all. There must be some other unknown factors involved. Altogether, while metabarcoding based on ribosomal genes remains a good first approach to document microbial eukaryotic clades, alternative approaches based on other genes or sequencing techniques must be considered for an unbiased picture of the diversity of some groups.
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Affiliation(s)
| | - Iván García-Cunchillos
- Institute of Evolutionary Biology, Biological and Chemical Research Centre, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Nicolas Henry
- Research Federation for the study of Global Ocean Systems Ecology and Evolution, Paris, France
- CNRS, FR2424, ABiMS, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Cédric Berney
- CNRS, FR2424, ABiMS, Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
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Singer D, Fouet MPA, Schweizer M, Mouret A, Quinchard S, Jorissen FJ. Unlocking foraminiferal genetic diversity on estuarine mudflats with eDNA metabarcoding. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:165983. [PMID: 37543334 DOI: 10.1016/j.scitotenv.2023.165983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/30/2023] [Accepted: 07/30/2023] [Indexed: 08/07/2023]
Abstract
Environmental biomonitoring is a prerequisite for efficient evaluation and remediation of ecosystem degradation due to anthropogenic pressure or climate change. Estuaries are key habitats subject to multiple anthropogenic and natural stressors. Due to these multiple stressors, the detection of anthropogenic pressure is challenging. The fact that abundant natural stressors often lead to negative quality assessments has been coined the "estuarine quality paradox". To solve this issue, the application of molecular approaches with successful bioindicators like foraminifera is promising. However, sampling protocols, molecular procedures and data analyses need to be validated before such tools can be routinely applied. We conducted an environmental DNA survey of estuarine mudflats along the French Atlantic coast, using a metabarcoding approach targeting foraminifera. Our results demonstrate that estuarine environments have only a few active OTUs dominating the community composition and a large stock of dormant or propagule stages. This last genetic diversity components constitute an important reservoir, with different species which can potentially develop in response to the temporal variability of the multiple stressors. In fact, different OTUs were dominant in the studied estuaries. Our statistical model shows that the physical and chemical characteristics of the sediment and the climatic conditions explain only 43 % of the community composition variance. This suggests that other, less easily quantifiable factors, such as the history and use of the estuaries or the ecological drift could play an important role as well. Environmental DNA biomonitoring opens new perspectives to better characterize the genetic diversity in estuaries.
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Affiliation(s)
- David Singer
- Université d'Angers, Nantes Université, Le Mans Université, CNRS, Laboratoire de Planétologie et Géosciences, LPG UMR 6112, 49000 Angers, France; Changins College for Viticulture and Enology, University of Sciences and Art Western Switzerland, Route de Duillier 60, 1260 Nyon, Switzerland.
| | - Marie P A Fouet
- Université d'Angers, Nantes Université, Le Mans Université, CNRS, Laboratoire de Planétologie et Géosciences, LPG UMR 6112, 49000 Angers, France
| | - Magali Schweizer
- Université d'Angers, Nantes Université, Le Mans Université, CNRS, Laboratoire de Planétologie et Géosciences, LPG UMR 6112, 49000 Angers, France
| | - Aurélia Mouret
- Université d'Angers, Nantes Université, Le Mans Université, CNRS, Laboratoire de Planétologie et Géosciences, LPG UMR 6112, 49000 Angers, France
| | - Sophie Quinchard
- Université d'Angers, Nantes Université, Le Mans Université, CNRS, Laboratoire de Planétologie et Géosciences, LPG UMR 6112, 49000 Angers, France
| | - Frans J Jorissen
- Université d'Angers, Nantes Université, Le Mans Université, CNRS, Laboratoire de Planétologie et Géosciences, LPG UMR 6112, 49000 Angers, France
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Geisen S, Lara E, Mitchell E. Contemporary issues, current best practice and ways forward in soil protist ecology. Mol Ecol Resour 2023; 23:1477-1487. [PMID: 37259890 DOI: 10.1111/1755-0998.13819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/23/2023] [Accepted: 05/17/2023] [Indexed: 06/02/2023]
Abstract
Soil protists are increasingly studied due to a release from previous methodological constraints and the acknowledgement of their immense diversity and functional importance in ecosystems. However, these studies often lack sufficient depth in knowledge, which is visible in the form of falsely used terms and false- or over-interpreted data with conclusions that cannot be drawn from the data obtained. As we welcome that also non-experts include protists in their still mostly bacterial and/or fungal-focused studies, our aim here is to help avoid some common errors. We provide suggestions for current terms to use when working on soil protists, like protist instead of protozoa, predator instead of grazer, microorganisms rather than microflora and other terms to be used to describe the prey spectrum of protists. We then highlight some dos and don'ts in soil protist ecology including challenges related to interpreting 18S rRNA gene amplicon sequencing data. We caution against the use of standard bioinformatic settings optimized for bacteria and the uncritical reliance on incomplete and partly erroneous reference databases. We also show why causal inferences cannot be drawn from sequence-based correlation analyses or any sampling/monitoring, study in the field without thorough experimental confirmation and sound understanding of the biology of taxa. Together, we envision this work to help non-experts to more easily include protists in their soil ecology analyses and obtain more reliable interpretations from their protist data and other biodiversity data that, in the end, will contribute to a better understanding of soil ecology.
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Affiliation(s)
- Stefan Geisen
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | | | - Edward Mitchell
- Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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Anthony MA, Bender SF, van der Heijden MGA. Enumerating soil biodiversity. Proc Natl Acad Sci U S A 2023; 120:e2304663120. [PMID: 37549278 PMCID: PMC10437432 DOI: 10.1073/pnas.2304663120] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/02/2023] [Indexed: 08/09/2023] Open
Abstract
Soil is an immense habitat for diverse organisms across the tree of life, but just how many organisms live in soil is surprisingly unknown. Previous efforts to enumerate soil biodiversity consider only certain types of organisms (e.g., animals) or report values for diverse groups without partitioning species that live in soil versus other habitats. Here, we reviewed the biodiversity literature to show that soil is likely home to 59 ± 15% of the species on Earth. We therefore estimate an approximately two times greater soil biodiversity than previous estimates, and we include representatives from the simplest (microbial) to most complex (mammals) organisms. Enchytraeidae have the greatest percentage of species in soil (98.6%), followed by fungi (90%), Plantae (85.5%), and Isoptera (84.2%). Our results demonstrate that soil is the most biodiverse singular habitat. By using this estimate of soil biodiversity, we can more accurately and quantitatively advocate for soil organismal conservation and restoration as a central goal of the Anthropocene.
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Affiliation(s)
- Mark A. Anthony
- Plant-Soil Interactions Unit, Research Division Agroecology and Environment, Agroscope, Zürich8046, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research, Forest Dynamics Research Unit, Birmensdorf8903, Switzerland
| | - S. Franz Bender
- Plant-Soil Interactions Unit, Research Division Agroecology and Environment, Agroscope, Zürich8046, Switzerland
- Department of Plant and Microbial Biology, University of Zürich, Zürich8008, Switzerland
| | - Marcel G. A. van der Heijden
- Plant-Soil Interactions Unit, Research Division Agroecology and Environment, Agroscope, Zürich8046, Switzerland
- Department of Plant and Microbial Biology, University of Zürich, Zürich8008, Switzerland
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