Biodiversity Data Journal :
Data Paper (Biosciences)
|
Corresponding author: Nina Filippova (filippova.courlee.nina@gmail.com)
Academic editor: Ning Jiang
Received: 30 Jan 2024 | Accepted: 19 Mar 2024 | Published: 27 Mar 2024
© 2024 Nina Filippova, Elena Zvyagina, Elena Rudykina, Tagir Ishmanov, Ilya Filippov, Tatiana Bulyonkova, Alevtina Dobrynina
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Filippova N, Zvyagina E, Rudykina EA, Ishmanov TF, Filippov IV, Bulyonkova TM, Dobrynina AS (2024) DNA-based occurrence dataset on peatland fungal communities studied by metabarcoding in north-western Siberia. Biodiversity Data Journal 12: e119851. https://doi.org/10.3897/BDJ.12.e119851
|
|
The paper represents the first DNA-based occurrence dataset on peatland fungal communities published for north-western Siberia, the first for Russia and complements several existing datasets on metabarcoding of peat soils globally.
The aim of the present publication is to describe the first DNA-based occurrence dataset on fungal communities in peat soils and other substrates studied by the eDNA approach in the Mukhrino raised bog, located in a large paludified area of north-western Siberia. A comparison of the species diversity of larger fungi identified by the conventional approach and by eDNA showed a high proportion of shared taxa. Other groups (mainly Ascomycota), described by metabarcoding, revealed high diversity compared with conventional observation. Overall, the species richness identified in one peatland locality (the Mukhrino Bog) was comparable in number of species to the global estimation of fungal diversity in peatlands, previously reported in literature.
peat, histosols, sphagnum, fungi, environmental DNA, eDNA, GBIF
Peatlands are a special ecosystem type that forms in humid conditions when large masses of organic carbon accumulate and form the peat layer in anoxic conditions (
The study of the fungal diversity of peatlands globally started over a century ago and was described in a series of reviews (
The metabarcoding of fungi has greatly improved the global estimate of fungal diversity and provided valuable insights into the ecological composition of fungal communities in various ecosystems (
This dataset complements a series of published open datasets on fungal communities in north-western Siberia and globally, complementing the complex approach to the research of peat soils (conventional observation, barcoding and metabarcoding):
The standardised approach for data storage of metabarcoding results in general and fungal metabarcoding specifically has been developed in recent years (
The study of the peatland fungal community in the vicinity of Mukhrino field station (the middle taiga zone of north-western Siberia) has been carried out for over a decade. The permanent plot-based monitoring of the fruiting dynamics of larger fungi was initiated in 2014 and continues to date with biweekly counts on 5 m2 circular plots on a total area of 1315 m2 (
To supplement direct observation of fruitbodies with an environmental DNA approach, we completed a series of samplings of common substrates in the same locality in the Mukhrino Bog. Four major substrates were subjected to metabarcoding analysis: peat (from the surface layer to a depth of about 3 m), leaf litter of six bog plants, wood (represented by standardised wooden dowels) and mycorrhizal roots of two bog-dwelling trees. Metabarcoding of the ITS2 region (Illumina MiSeq platform) revealed about 1200 OTUs and 800 Linnean taxa. The community analysis of different substrates, based on metabarcoding results, showed significant differences between all four substrates; a high difference between two different bog habitats (hummocks and hollows); a significant difference between all litter types of bog plants; and an insignificant difference between the roots of two bog pine species. The results also showed a high influence of season on community composition (from the beginning to the end of summer) and a high influence of peat depth parameter for the community of peat substrate.
The taxonomic diversity revealed by the eDNA approach was compared with earlier results at three levels: 1) with the global literature-based checklist of fungi in peatlands based on a literature dataset; 2) with the accumulated checklist of fungi in the Mukhrino Bog, based on an earlier conventional approach; 3) to verify both approaches at more strict limits, we made the comparison of larger fungi (Agaricomycetes) revealed most thoroughly in the Mukhrino Bog by a ten-year direct observation period with the same group revealed by eDNA analysis.
In order to study the fungal community of raised bogs, four major substrates were subjected to metabarcoding analysis: peat (from the surface layer to about 3 m depth), plant litter (6 plant species), wood (standardised wooden dowels) and mycorrhizal roots (Pinus sylvestris L., P. sibirica Du Tour) (Fig.
Four substrates studied by metabarcoding analyses: A – peat (from the surface layer to about 3 m depth, the surface sample from 0-5 cm depth shown as example); B – plant litter (Eriophorum vaginatum L. dead leaves shown as example); C – wood (standardised wooden dowels); D – mycorrhizal roots of P. sylvestris and P. sibirica.
Layout of the Mukhrino field station infrastructure and position of plots (Hu – hummock, Ho – hollow) where metabarcoding samples were extracted (plots used only for peat and leaf litter samples); red dots mark the position of circular 5 m2 plots for monitoring larger fungi; lower right insert: overview of two habitats (hummock and hollow).
All field operations were made wearing gloves and the instruments (knife, scissors and tweezers when necessary) were sterilised between samples with bleach and alcohol according to recommendations (
Sampling of peat and eDNA extraction protocol
To study the fungal community of peat, six plots were located in two habitats: hummocks and hollows (Fig.
All samples were soaked in 400 µl of lysis buffer overnight, then homogenised using a micro-tube homogeniser with glass beads according to manufacturer instructions (total DNA extraction soil kit, SileksMagNA) (Fig.
Sample preparation of peat: A – freeze-dried sample of Sphagnum fuscum (Schimp.) H.Klinggr. (about 5 g field weight), B – homogenisation using a pestle and a mortar, C – approximately 0.05 g of peat powder pooled from each sample (to be further processed according to manufacturer instructions).
This experiment design resulted in a total of 46 samples with the following environmental variables for analysis: habitat (2 types), species of Sphagnum (6 species), peat depth (4 depths) and seasonal variation (4 dates); and experimental variables to test: the efficiency of sampling approach (composite 5 g vs. single 0.05 g samples); the efficiency of sample homogenisation and extraction replicas (Fig.
Sampling of plant litter and eDNA extraction
The community of fungal saprotrophs of the six common plant species was studied by collecting their leaf litter: Rhododendron groenlandicum (Oeder) Kron & Judd, Chamaedaphne calyculata (L.) Moench, Rubus chamaemorus L. (in hummock habitats), Andromeda polifolia L., Eriophorum vaginatum L. and Scheuchzeria palustris L. (in hollow habitats). The litter was picked randomly from the surface of Sphagnum over an area of approximately 10 m2 in each plot. Sampling was performed in the same plots and on the same dates as the peat substrate (see above). A total of 5 g of field weight substrate of each plant was collected three times per season (June, July and September), totalling 28 samples.
All samples were packed in sterile paper bags and dried in a dehydrator at 40°C. Each sample was then ground in a coffee grinder (all parts were sterilised between the samples) in order to break down hard plant material and homogenise the composite sample. From each composite sample, about 0.05 g of plant powder was transferred to a 1.5 ml Eppendorf tube, soaked and homogenised with a lysis buffer as above (Fig.
Sampling of mycorrhizal roots and eDNA extraction
To study the mycorrhizal community of bog trees, we collected the ectomycorrhizal roots of two common bog-dwelling trees: P. sylvestris and P. sibirica. The roots were collected in two localities («Mukhrino» and «Shapsha», located about 30 km from each other across the Ob-Irtysh River confluence) for geographical variability. In each locality, 5 to 10 trees growing about 10 m apart were marked for the following root extraction and dendrochronological boring. Sampling was done twice a year at the beginning and at the end of the vegetation season (June and September), producing a total of 40 root samples. About 30 g of fine roots were extracted from samples taken about 20–30 cm apart in several sites around each tree trunk. The samples were additionally cleaned from fine debris in the laboratory; the cleaned roots were collected in Eppendorf tubes (about 0.5 ml volume) and frozen (Fig.
Sampling of wood and eDNA extraction
To study the total DNA of the dead wood community, we used an approach of standardised substrates (
DNA detection, library preparation, PCR and sequencing
A total of 144 samples of environmental DNA, extracted from four substrates, were obtained and stored at −20°C until being processed. The samples of extracted DNA were outsourced for processing by an independent company (Evrogen, Moscow). The quality of the obtained metagenomic DNA was checked by electrophoresis on an agarose gel. Quantification was carried out by measuring the concentration of DNA by Qubit 2, using the dsDNA HS reagent kit (ThermoFisher Scientific). The preparation of libraries for sequencing was carried out in accordance with the protocol described in 16S Metagenomic Sequencing Library Preparation (Part #15044223 Rev. B; Illumina). Amplification of ITS variable regions was carried out using primers: fITS7: 5'-GTGARTCATCGAATCTTTG-3' and ITS4: 5'-TCCTCCGCTTATTGATATGC-3' (
Raw data storage. The raw reads (FastQ archives and a metadata table) were uploaded to NCBI Sequence Reads (bioproject accession number PRJNA1007262).
Sequence processing and bioinformatics pipeline
The obtained sequences were processed using QIIME2 (Quantitative Insights Into Microbial Ecology 2, version 2023.9).
The pipeline of sequence analysis is applied as follows:
Curated sequence classification
To make the automatic classification plausability check, manual curated sequence classification was performed for the most locally studied group of larger agaricoid fungi:
The study sites are the Mukhrino field station and the Mukhrino Bog, which are located in the middle taiga zone of Western Siberia, near the regional capital city of Khanty-Mansiysk (
60.89151 and 61.06549 Latitude; 68.67719 and 69.45882 Longitude.
The sequence analysis revealed a total of 1259 OTUs classified into 471 species, 423 genera, 223 families, 86 orders, 30 classes, seven phyla and one kingdom at a 99% similarity level. About 42% of taxa were identified at the species level, 21% at the genus level and the rest at higher taxonomic levels (Table
Taxonomic structure of fungal community revealed by sequence analysis of eDNA in Mukhrino Bog.
Kingdom |
Phyla |
Class |
Order |
Family |
Genus |
Species |
|
Total number of taxa |
1 |
7 |
30 |
86 |
223 |
423 |
471 |
Number of OTUs identified to this level |
32 |
67 |
83 |
152 |
131 |
267 |
527 |
Percentage of OTUs identified to this level |
3% |
5% |
7% |
12% |
10% |
21% |
42% |
To compare the revealed taxonomic diversity with earlier published results, we used several checklists of fungi in peatlands:
Number and percentage of species shared by different checklists (global literature-based dataset, metabarcoding results in the Mukhrino Bog and conventional approach in the Mukhrino Bog): A. a matrix of percentage (lower part) and number of shared species (upper part) between each two lists; B. a diagram showing percentage of species shared by several checklists.
Curated sequence classification results
The curated sequence classification showed quite significant differences when compared at the species level. Both classifications showed 100% similarity at the class, order, family and genus taxonomical ranks. However, at the species level, 23% species (27 from 118) were assigned different names as a result of curated classification: nine species were re-identified as other species, 14 taxa improved identification to species level and four species were reduced to genus level (Table
Curated sequence classification results and comparison with machine identification at species level
ID | Machine identification | Curated identification | Curation type |
1 | Cortinarius pluvius (Fr.) Fr. 1838 | Cortinarius sp. 9 | reduced to genus level |
2 | Lepiota neophana Morgan | Lepiota sp. | |
3 | Mycena semivestipes (Peck) A.H. Sm. 1947 | Mycena sp. 2 | |
4 | Tomentella longisterigmata X. Lu, K. Steffen & H.S. Yuan 2018 | Tomentella sp. | |
5 | Bovista promontorii Kreisel 1967 | Bovista aestivalis (Bonord.) Demoulin 1979 | re-identified to other species |
7 | Cortinarius hydrotelamonioides Rob. Henry 1970 | Cortinarius kauffmanianus A.H. Sm. | |
8 | Cortinarius paleaceus Fr. 1838 | Cortinarius lindstroemii Niskanen, Kytov. & Liimat. 2020 | |
9 | Flammula abieticola (A.H. Sm. & Hesler) E.J. Tian & Matheny 2020 | Flammula alnicola (Fr.) P. Kumm. 1871 | |
10 | Galerina calyptrata P.D. Orton 1960 | Galerina cf. calyptrata P.D. Orton 1960 | |
11 | Inocybe tigrina R. Heim 1931 | Inocybe flocculosa Sacc. 1887 | |
12 | Lentinellus flabelliformis (Bolton) S. Ito 1959 | Lentinellus micheneri Lentinellus micheneri | |
13 | Suillus subluteus (Peck) Snell 1944 | Suillus praetermissus Zvyagina & Svetash. 2021 | |
14 | Lactarius Pers. 1797 | Lactarius tabidus Fr. 1838 | improved identification to species level |
15 | Cortinarius (Pers.) Gray 1821 | Cortinarius bataillei (J. Favre ex M.M. Moser) Høil. 1984 | |
16 | Cortinarius (Pers.) Gray 1821 | Cortinarius glandicolor (Fr.) Fr. 1838 | |
17 | Cortinarius (Pers.) Gray 1821 | Cortinarius kauffmanianus A.H. Sm. 1933 | |
18 | Cortinarius (Pers.) Gray 1821 | Cortinarius lindstroemii Niskanen, Kytov. & Liimat. 2020 | |
19 | Cortinarius (Pers.) Gray 1821 | Cortinarius ominosus Bidaud 1994 | |
20 | Cortinarius (Pers.) Gray 1821 | Cortinarius tenuifulvescens Kytöv., Niskanen & Liimat. 2016 | |
21 | Cortinarius (Pers.) Gray 1821 | Cortinarius bicolor Cooke 1887 | |
22 | Cortinarius (Pers.) Gray 1821 | Cortinarius collinitus (Sowerby) Gray 1821 | |
23 | Hypholoma (Fr.) P. Kumm. 1871 | Bogbodia uda (Pers.) Redhead 2013 | |
24 | Lycoperdon Pers. 1794 | Lycoperdon perlatum Pers. 1796 | |
25 | Cortinariaceae | Cortinarius glandicolor (Fr.) Fr. 1838 | |
26 | Cortinariaceae | Cortinarius collinitus (Sowerby) Gray 1821 | |
27 | Cortinariaceae | Thaxterogaster causticus (Fr.) Niskanen & Liimat. 2022 |
Rank | Scientific Name |
---|---|
kingdom | Fungi |
2022-06-01 through 2022-09-01
This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.
The dataset representing DNA-based occurrences published in GBIF as an occurrence dataset with the DNA-derived extension table based on guidelines (
Column label | Column description |
---|---|
occurrenceID (Occurrence core) | A unique identifier for the occurrence. |
scientificName (Occurrence core) | An OTU identifier from UNITE. |
scientificNameAuthorship (Occurrence core) | The authorship information for the scientificName. |
Kingdom (Occurrence core) | The full scientific name of the kingdom in which the taxon is classified. |
Phylum (Occurrence core) | The full scientific name of the phylum in which the taxon is classified. |
Class (Occurrence core) | The full scientific name of the class in which the taxon is classified. |
Order (Occurrence core) | The full scientific name of the order in which the taxon is classified. |
Family (Occurrence core) | The full scientific name of the family in which the taxon is classified. |
Genus (Occurrence core) | The full scientific name of the genus in which the taxon is classified. |
specificEpithet (Occurrence core) | The name of the first or species epithet of scientificName. |
eventID (Occurrence core) | An identifier for the set of information associated with an Event (sample number). |
organismQuantity (Occurrence core) | Number of reads of this OTU in this sample. |
organismQuantityType (Occurrence core) | "DNA sequence reads". |
habitat (Occurrence core) | A category or description of the habitat in which the dwc:Event occurred ("Treed pine-dwarfshrubs-sphagnum ombrotrophic raised bog" or "Graminoid-sphagnum lawn of ombrotrophic raised bog"). |
sampleSizeValue (Occurrence core) | Total number of reads in the sample. |
sampleSizeUnite (Occurrence core) | "DNA sequence reads". |
decimalLatitude (Occurrence core) | The geographic latitude where the dwc:Event occurred (exact locality of the sample collection). |
decimalLongitude (Occurrence core) | The geographic longitude where the dwc:Event occurred (exact locality of the sample collection). |
eventRemarks (Occurrence core) | Substrate type ("Mycorrhizal roots", "Peat", "Wooden dowels" and "Plant litter") and peat depth. |
associatedTaxa (Occurrence core) | A name of plant from which the sample was collected (for example, "host":"Pinus sylvestris"). |
eventDate (Occurrence core) | Date when the sampling of substrate was made. |
country (Occurrence core) | A name of the country where the sampling occurred ("Russia"). |
countryCode (Occurrence core) | The standard code for the country ("RU"). |
geodeticDatum (Occurrence core) | The geodetic datum ("WGS84"). |
coordinateUncertaintyInMetres (Occurrence core) | The coordinate uncertanty (all coordinates taken with GPS with uncertainty about 30 m). |
ID (DNA-derived extension) | A unique identifier for the occurrence refers to the occurrence table (occurrenceID). |
DNA_sequence (DNA-derived extension) | The DNA sequence (OTU). |
sop (DNA-derived extension) | Standard operating procedures used in assembly and/or taxonomic annotation of reads. |
target_gene (DNA-derived extension) | Targetted gene or marker name for marker-based studies (ITS). |
target_subfragment (DNA-derived extension) | Name of subfragment of a gene (ITS2). |
pcr_primer_forward (DNA-derived extension) | Forward PCR primer ("GTGARTCATCGAATCTTTG"). |
pcr_primer_reverse (DNA-derived extension) | Reverse PCR primer ("TCCTCCGCTTATTGATATGC"). |
pcr_primer_name_forward (DNA-derived extension) | Name of the forward PCR primer ("Next-fITS7"). |
pcr_primer_name_reverse (DNA-derived extension) | Name of the reverse PCR primer ("Next-ITS4"). |
pcr_primer_reference (DNA-derived extension) | Reference for the primers (doi.org/10.1111/j.1574-6941.2012.01437.x). |
env_broad_scale (DNA-derived extension) | The major environmental system using subclasses of ENVO’s biome class ("peatland"). |
lib_layout (DNA-derived extension) | The configuration of reads ("paired"). |
seq_meth (DNA-derived extension) | Sequencing method used ("Illumina MiSeq"). |
otu_class_appr (DNA-derived extension) | Approach/algorithm and clustering level ("Internal de-novo clustering with an identity parameter of 99% (QIIME vsearch cluster-features-de-novo)"). |
otu_seq_comp_appr (DNA-derived extension) | Tool and thresholds used to assign "species-level" names to OTUs ("Classification classify-sklearn (QIIME feature-classifier classify-sklearn) on a classifier that was trained using the naive Bayes classifier algorithm (QIIME feature-classifier fit-classifier-naive-bayes)"). |
otu_db (DNA-derived extension) | Reference database ("Clustering based on the UNITE database (version 9.0 16 October 2022) using cluster-features-closed-reference with 97% identity parameter (QIIME vsearch cluster-features-closed-reference)"). |
taxonRank (Occurrence core) | The taxonomic rank of the scientificName. |
basisOfRecord (Occurrence core) | The specific nature of the data record ("materialSample"). |
The table presents supplementary materials and contains metadata on sampling strategy during metabarcoding analysis of four types of substrates in two ombrotrophic bog habitats, with other experimental and environmental parameters included in the analyses.
Column label | Column description |
---|---|
Sample_ID | A unique identifier of the sample. |
eventDate | Date when the sampling of substrate was made. |
Substrate | Substrate of the sample ("Mycorrhizal roots", "Plant litter", "Wooden dowels", "Peat"). |
Conservation | Conservation method of the sample ("Drying", "Freezing"). |
DNA_extraction_kit | DNA extraction kit ("SileksMagNA"). |
Sampling_approach | Sampling approach ("Composite from 5 points 5 m apart, totalling in 5 g of fresh weight", "Single sample from one point, 0.25 g of fresh weight"). |
Extraction_repica | Extraction replica, if existing. |
Depth | Depth at which the sample was extracted (applied for "Peat" in "Substrate"). |
Vegetation | Vegetation type where the sample was extracted ("Graminoid-sphagnum lawn of ombrotrophic raised bog", "Treed pine-dwarfshrubs-sphagnum ombrotrophic raised bog"). |
Locality | Locality name where the sample was extracted ("Mukhrino field station, Mukhrino Bog, |
Plot_number | Plot number where the sample was extracted. |
Plant_host | Plant host from which plant litter or mycorrhizal roots were extracted (totally 16 plant hosts). |
Number_of_reads | Total number of reads in this sample. |
The paper presents metabarcoding data on fungal communities of peat and other substrates sampled in the raised bog Mukhrino in north-western Siberia. Two datasets were published in open source depositories: a DNA-derived occurrence dataset published in GBIF and sequence reads archive of raw FastQ files published in NCBI. The methods of experiment design, sampling, bioinformatic piplines and data resources are described in detail. The layout of the data paper is resresented in Fig.
A grant for the organisation of a new laboratory for young researchers at Yugra State University as part of the implementation of the National Project "Science and Universities".
N. Filippova, E. Zvyagina - work on manuscript; I. Filippov, T. Ishmanov, E. Zvyagina, N. Filippova - work on data analyses; E. Rudykina, A. Dobrynina, N. Filippova - field sampling and laboratory sample processing; T. Bulyonkova - editing and translation.