Profile fungal communities. From soil to clinic.
End-to-end Internal Transcribed Spacer (ITS) amplicon sequencing and analysis for fungal community characterisation across environmental, agricultural and clinical samples — targeting the standard fungal barcoding marker.
Fungal barcoding via ITS1 / ITS2
Nucleome Informatics offers end-to-end ITS amplicon sequencing and data analysis services for fungal community characterisation across environmental, agricultural and clinical samples.
The ITS region is the standard fungal barcoding marker. Sequencing of the ITS1 or ITS2 sub-region provides taxonomic resolution of fungal communities in a targeted, cost-effective manner.
Our analysis combines sequencing quality control, primer and adapter trimming, denoising into amplicon sequence variants (ASVs), chimera removal and taxonomic classification against curated fungal reference databases, along with diversity and comparative community analysis.
- Amplicon sequencing data quality assessment and preprocessing
- Primer trimming and quality filtering of ITS1/ITS2 reads
- Denoising into amplicon sequence variants (ASVs)
- Chimera detection and removal
- Taxonomic classification against curated fungal reference databases
- Alpha- and beta-diversity analysis
- Comparative and differential abundance analysis across groups
- Secure delivery of raw, intermediate and final analysis files
ASV-Based Resolution
Denoising-based resolution of amplicon sequence variants delivers improved taxonomic accuracy over traditional OTU clustering — resolving true biological variants rather than arbitrary clusters.
Flexible Marker Choice
Choose ITS1 or ITS2 targeting to suit your study objectives and the taxonomic resolution your questions require.
Built for fungal community analysis
From marker selection through diversity statistics — a workflow designed for reproducible, high-resolution fungal profiling.
ITS1 / ITS2 Targeting
Flexible marker-region selection to suit study objectives and taxonomic resolution requirements.
ASV-Based Analysis
Denoising-based resolution of amplicon sequence variants for improved accuracy over traditional OTU clustering.
Curated Fungal Databases
Taxonomic assignment using established, curated fungal ITS reference databases.
Chimera-Checked Workflow
Systematic detection and removal of chimeric sequences prior to taxonomic assignment.
Diversity Analysis
Alpha- and beta-diversity metrics with group-wise statistical comparisons.
Comparative Analysis
Community composition and abundance compared across samples or experimental groups.
From first principles to expert-level analysis
New to fungal community sequencing? Start with Foundations. Planning a study or reviewing results? Jump to Practitioner or Expert. Each level builds on the one before it, so you can read this page as a short course or dip in where you need to.
The big idea in plain language: every fungus carries a stretch of DNA called ITS that works like a species barcode. Reading that barcode from a sample tells you which fungi are present and in what proportions.
Fungi are everywhere, mostly unseen
Soil, plant roots, indoor air, skin and gut all hold diverse fungal communities. Most fungi are microscopic and cannot be grown easily, so DNA is the practical way to identify them.
ITS is the fungal barcode
The internal transcribed spacer (ITS) sits between ribosomal genes. It changes quickly enough to separate species, which is why it is the standard fungal barcoding marker.
ITS1 or ITS2
The ITS has two variable sub-regions, ITS1 and ITS2, separated by the short 5.8S gene. Primers copy one of them from every fungus in the sample at once.
Reads become variants, then names
The sequencer reads millions of copies. Software removes errors, groups identical sequences into amplicon sequence variants (ASVs), and matches each to a curated fungal reference database to give it a name.
Diversity in two questions
Alpha diversity asks how rich and even one sample is. Beta diversity asks how different two samples are from each other.
Which fungi differ?
Comparative analysis checks groups, such as treated versus control soil, and lists the fungi that are consistently more or less abundant.
For scientists planning a project or reading a report: how design choices and quality control decide whether a fungal profile can be trusted.
ITS length varies
Unlike 16S, ITS products differ in length between species. Reads should therefore not be cut to one fixed length. Primers are trimmed instead, and reads are filtered on quality and expected errors.
Choosing ITS1 or ITS2
Primer sets for each sub-region favour different groups, and no single pair captures every fungus equally. The choice depends on the taxa and sample types you care about.
Primer removal comes first
Primers must be clipped before denoising, otherwise leftover primer bases confuse error learning and chimera checks. Reads without primers are usually discarded.
Curated fungal databases
Fungal names change often, so assignment relies on curated resources. UNITE groups ITS sequences into species hypotheses, with nearly 10 million reference sequences in the 2024 description.
Depth and rarefaction
A rarefaction curve shows whether more sequencing would still reveal new ASVs. Fungal soil communities are rich, so curves often rise for longer than in simple communities.
Controls and replicates
Extraction blanks, a fungal mock community and enough biological replicates tell you how much of what you see is signal, contamination or batch effect.
For method developers and reviewers: the biological and statistical caveats that decide whether an apparent result holds up.
ASV or OTU?
ASVs resolve exact sequences, but fungal ITS can differ between copies within one genome. A 2022 best-practice review argued OTUs can recover fungal diversity better than ASVs for long markers, so the choice should match the question.
Copy-number bias
Across 91 fungi with sequenced genomes, rDNA copy number ranged from about 14 to 1,442. Read counts therefore reflect gene copies, not cell numbers, and should not be read as biomass.
Intragenomic variation
In a survey of 2,414 fungal genomes, 641 species carried more than one ITS copy and 419 of those had copies that differed. One organism can then appear as several ASVs.
Compositional statistics
Sequencing returns proportions, so a bloom in one fungus makes others look lower. Compositionally aware methods such as ANCOM-BC, ALDEx2 and CLR-based models are designed for this.
Primer and length bias
In a gut mycobiome comparison, ITS primers showed amplification bias and longer products above about 600 bp were under-represented. Mock communities reveal such biases.
Full-length ITS
The same best-practice review reported that the full-length ITS region places fungi more accurately than ITS2 alone, which is relevant to long-read designs.
- ITS
- Internal transcribed spacer: the fungal barcode region between the ribosomal genes.
- ASV
- Amplicon sequence variant: an exact, error-corrected sequence.
- OTU
- Operational taxonomic unit: a cluster of similar sequences, often at 97% identity.
- Species hypothesis
- A UNITE group of ITS sequences treated as a putative species.
- Phred Q30
- A base-call quality score meaning about 1 error in 1,000 bases.
- Chimera
- An artefactual sequence stitched from two parents during PCR.
- Alpha / beta
- Diversity within one sample, and dissimilarity between samples.
- CLR
- Centred log-ratio: a transform for proportion data.
How a barcode region becomes a fungal profile
These schematics show the region we target, what happens to a sample on its way to reads, and why fungal ITS data need extra care compared with bacterial 16S.
DNA extraction
Tough fungal cell walls are broken open and DNA is purified from soil, plant tissue, swabs or clinical material.
Amplify ITS1 or ITS2
PCR with fungal-targeting primers copies the chosen sub-region from every fungus at once.
Index and pool
A second short PCR adds a unique index per sample, so many samples can share one run.
Paired-end sequencing
Both ends of each amplicon are read, giving overlapping reads that are later merged.
From raw reads to community profiles
Each sample passes through a quality-controlled analysis workflow designed to move from raw amplicon sequencing data to annotated fungal community profiles.
Raw data QC
Per-base quality, adapter and primer content are reviewed for every sample.
Primer trimming & filtering
ITS1 or ITS2 primers are clipped, then reads are filtered on quality and expected errors without forcing one fixed length.
Denoising
The run's error model is learned and exact sequence variants (ASVs) are inferred per sample.
Chimera removal
PCR chimeras are detected and removed before classification.
Taxonomic assignment
ASVs are classified against curated fungal ITS reference databases.
Diversity analysis
Alpha metrics, beta-diversity distances and ordination to describe richness and composition.
Comparative analysis
Community composition and abundance compared across samples or groups, with FDR control.
Reporting & delivery
Taxonomic profiles, diversity statistics and QC summaries shared through secure storage.
Data QC & Pre-processing
Sequencing quality assessed; primer trimming and quality filtering of ITS reads.
Denoising / ASV Generation
Quality-filtered reads denoised into amplicon sequence variants.
Chimera Removal
Chimeric sequences identified and removed for accurate classification.
Taxonomic Assignment
ASVs classified against curated fungal ITS reference databases.
Diversity Analysis — Alpha- and beta-diversity metrics to characterise community richness and composition.
Comparative Analysis — Community composition and abundance compared across samples or groups.
Reporting & Delivery — Taxonomic profiles, diversity statistics and QC summaries delivered securely.
Trust the data before you trust the biology
Every downstream result depends on clean reads. These interactive plots use simulated data to show what good and poor quality look like, and why denoising matters.
Within samples and between them
Alpha diversity summarises one community. Beta diversity compares communities and is the basis of most group comparisons. All plots below are simulated to illustrate the outputs you receive.
Finding the taxa that really differ
Tests ask which fungal taxa are more or less abundant between groups. Effect size and statistical confidence should be read together, with false discovery rate control across all taxa tested.
| Method | Idea | Good for |
|---|---|---|
| DESeq2 | Negative-binomial model on counts | Sensitive; widely used; watch composition effects |
| ANCOM-BC | Bias-corrected log-ratio model | Compositional data; good false-positive control |
| ALDEx2 | CLR on Monte Carlo draws | Small samples; conservative |
| LEfSe | Rank tests plus LDA effect size | Exploratory biomarker discovery |
Structured outputs for community biology
At project completion, clients receive a structured set of sequencing, analysis and reporting outputs via secure shared storage.
Raw & Processed Data
FASTQ files — raw and processed amplicon sequence data.
QC Reports
Sample-level sequencing and preprocessing QC summaries.
ASV Tables
Amplicon sequence variant count tables per sample.
Taxonomic Tables
Taxonomy assigned to each ASV at available ranks.
Diversity Summaries
Alpha- and beta-diversity metrics, ordination plots and group comparisons.
Summary Report
Sample-wise QC, ASV and taxonomic-assignment statistics.
Secure Delivery
Project files via secure shared storage or cloud access.
Comparative Outputs
Group-wise abundance and composition comparisons when designed.
What we accept
Flexible input options for sequencing-plus-analysis or analysis-only projects.
DNA from Diverse Matrices
We accept genomic DNA extracted from soil, plant tissue, environmental swabs, clinical samples or other relevant matrices, as well as pre-generated amplicon sequencing data where analysis-only services are required.
Project-specific requirements for DNA quantity, concentration, purity, primer selection and sequencing depth are finalised according to the study design.
Contact us for a project-specific sample submission checklist and recommended sequencing depth.
Soil · Plant · Environmental · Clinical
or pre-generated FASTQ
Proven on real fungal communities
Production metrics from soil fungal profiling and comparative community studies.
Soil Fungal Community Profiling
Multi-sample · ASV generation · Taxonomic classification
| Mean raw-data Q30 | 93.4% |
| Mean processed-data Q30 | 97.2% |
| Mean reads passing filter | ~88% |
| Mean ASVs per sample | ~410 |
| Mean genera identified | ~95 |
The study achieved high sequencing quality and consistent ASV recovery, with taxonomic profiles and diversity statistics delivered alongside a project summary report.
Comparative Fungal Community Analysis
Treatment groups · Replicate cohorts
| ASV recovery | Consistent |
| Diversity metrics | Reproducible |
| Technical replicates | Supported |
| Group-wise comparisons | Enabled |
| Differential abundance | Available |
In production studies, we have observed consistent ASV recovery and reproducible diversity metrics across technical replicates, supporting robust group-wise comparisons.
What ITS sequencing can tell you, and where the field is heading
ITS amplicon sequencing is the workhorse of fungal ecology and mycobiome research. Recent studies show both its power and the biological quirks that need careful handling.
| Approach | Strengths | Watch-outs |
|---|---|---|
| ITS1 (short reads) | Established primer sets; good species-level signal for many groups | Primer bias against some lineages; variable product length |
| ITS2 (short reads) | Widely used; broad reference coverage | Can amplify plant DNA in host samples; less accurate placement than full-length ITS in one review |
| Full-length ITS (long reads) | More accurate taxonomic placement in a 2022 reanalysis | Higher cost per read; fewer reads per run |
| 18S / 28S markers | Fewer length and primer-mismatch problems in a gut mock community | Less species-level resolution; smaller reference sets for fungi |
UNITE species hypotheses
The 2024 UNITE description reports nearly 10 million reference ITS sequences grouped into about 2.4 million species hypotheses, each with a DOI so studies can cite them unambiguously (Abarenkov et al., 2024).
ASV or OTU
A 2022 review of fungal metabarcoding reported that OTUs recovered fungal diversity better than ASVs for long markers, while ASVs give exact, reusable sequences. Reporting both views is a practical safeguard.
Compositional methods
The same review found that methods designed for compositional data gave more reliable estimates of shifts in community structure than methods that ignore composition.
Extraction and primers
A gut mycobiome study found that DNA extraction kits favoured some species, and that ITS primers showed amplification bias and under-represented long products (Frau et al., 2019).
Controls matter
Reagent and environmental contaminants matter most when little DNA is present. Extraction blanks and statistical decontamination help flag them (Davis et al., 2018).
Mock communities
A defined mixture of fungal species run alongside samples shows how accurately a workflow recovers composition and makes batches comparable.
Service highlights
End-to-end support for research, environmental, agricultural and clinical ITS projects.
End-to-End ITS Analysis
From raw amplicon sequencing data through QC, ASV generation, taxonomic classification and reporting.
ASV-Based Resolution
Denoising-based approach for improved taxonomic accuracy over traditional clustering methods.
Curated Fungal Databases
Reliable taxonomic assignment using established, curated ITS reference databases.
Transparent QC
Sample-wise and cohort-level quality metrics incorporated into project reporting.
Flexible Study Design
Support for individual samples, cohorts and comparative community studies.
Secure Data Delivery
Raw, intermediate and final datasets delivered through secure project storage.
Frequently asked, in plain language
From the basics to the finer points of study design and statistics.
basicWhat is ITS amplicon sequencing?
basicWhich samples can I send?
basicWhat will I receive?
intermediateShould I choose ITS1 or ITS2?
intermediateWhy are ITS reads not trimmed to one length?
intermediateWhich database is used for naming fungi?
advancedDo ASV counts equal the number of fungal species?
advancedDoes read abundance reflect how much of each fungus is present?
advancedWhy might different statistical tests disagree?
Key literature & resources
Selected sources behind the methods and reference values on this page. Figures labelled "simulated", "schematic" or "illustrative" are generated for this page, not client data.
- Schoch CL, et al. Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for Fungi. PNAS 2012;109:6241–6246.
- Tedersoo L, Bahram M, Zinger L, Nilsson RH, Kennedy PG, Yang T, Anslan S, Mikryukov V. Best practices in metabarcoding of fungi: from experimental design to results. Molecular Ecology 2022;31:2769–2795. Record
- Abarenkov K, et al. The UNITE database for molecular identification and taxonomic communication of fungi and other eukaryotes: sequences, taxa and classifications reconsidered. Nucleic Acids Research 2024;52:D791–D797. Record
- Nilsson RH, et al. Mycobiome diversity: high-throughput sequencing and identification of fungi. Nature Reviews Microbiology 2019;17:95–109.
- Bradshaw MJ, et al. Extensive intragenomic variation in the internal transcribed spacer region of fungi. iScience 2023;26. Record
- Lofgren LA, et al. Genome-based estimates of fungal rDNA copy number variation across phylogenetic scales and ecological lifestyles. Molecular Ecology 2019;28:721–730. Record
- Frau A, et al. DNA extraction and amplicon production strategies deeply influence the outcome of gut mycobiome studies. Scientific Reports 2019;9:9328. Link
- Callahan BJ, et al. DADA2: high-resolution sample inference from Illumina amplicon data. Nature Methods 2016;13:581–583.
- Callahan BJ, McMurdie PJ, Holmes SP. Exact sequence variants should replace operational taxonomic units in marker-gene data analysis. ISME Journal 2017;11:2639–2643.
- Martin M. Cutadapt removes adapter sequences from high-throughput sequencing reads. EMBnet.journal 2011;17:10–12.
- Gardes M, Bruns TD. ITS primers with enhanced specificity for basidiomycetes: application to the identification of mycorrhizae and rusts. Molecular Ecology 1993;2:113–118.
- Ihrmark K, et al. New primers to amplify the fungal ITS2 region: evaluation by 454-sequencing of artificial and natural communities. FEMS Microbiology Ecology 2012;82:666–677.
- Bengtsson-Palme J, et al. Improved software detection and extraction of ITS1 and ITS2 from ribosomal ITS sequences of fungi and other eukaryotes for analysis of environmental sequencing data. Methods in Ecology and Evolution 2013;4:914–919.
- Kõljalg U, et al. Towards a unified paradigm for sequence-based identification of fungi. Molecular Ecology 2013;22:5271–5277.
- McMurdie PJ, Holmes S. phyloseq: an R package for reproducible interactive analysis and graphics of microbiome census data. PLoS ONE 2013;8:e61217.
- Anderson MJ. A new method for non-parametric multivariate analysis of variance. Austral Ecology 2001;26:32–46.
- Love MI, Huber W, Anders S. Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biology 2014;15:550.
- Lin H, Peddada SD. Analysis of compositions of microbiomes with bias correction. Nature Communications 2020;11:3514.
- Gloor GB, et al. Microbiome datasets are compositional: and this is not optional. Frontiers in Microbiology 2017;8:2224.
- Yang L, Chen J. A comprehensive evaluation of microbial differential abundance analysis methods: current status and potential solutions. Microbiome 2022;10. Record
- Davis NM, et al. Simple statistical identification and removal of contaminant sequences in marker-gene and metagenomics data. Microbiome 2018;6:226.









