# maarjAM database
**URL:** https://forum.qiime2.org/t/maarjam-database/33257
**Category:** General Discussion
**Created:** [June 6, 2025, 3:31am UTC](https://forum.qiime2.org/t/maarjam-database/33257 "2025-06-06T03:31:36Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Salma\_Sarker](https://forum.qiime2.org/u/Salma_Sarker)
#### Post date: [June 6, 2025, 3:31am UTC](https://forum.qiime2.org/t/maarjam-database/33257/1 "2025-06-06T03:31:36Z")
Hi QIIME2 community,
I’m currently working on the analysis of arbuscular mycorrhizal fungi (AMF) using the 18S rRNA gene region (primers AMV4.5NF and AMDGR). I have already completed denoising with DADA2 and obtained my ASV representative sequences. I would now like to assign taxonomy using the MaarjAM database, which is specific to AMF.
However, I’m having trouble locating a QIIME2-compatible version of the MaarjAM database. Specifically, I’m looking for:
- A reference sequence FASTA file
- A corresponding taxonomy mapping file
- Or ideally, a pre-trained `.qza` classifier for use with `qiime feature-classifier classify-sklearn`
I’ve searched the MaarjAM website ([http://maarjam.botany.ut.ee/](http://maarjam.botany.ut.ee/)) but couldn’t find clear download options for the full reference database in a format suitable for QIIME2.
**Questions:**
1. Is there a QIIME2-compatible version of the MaarjAM database available for public use?
2. Has anyone successfully trained a classifier using this database for AMF taxonomy assignment?
3. If not, could someone kindly guide me through the process of converting the MaarjAM database into QIIME2 format?
---
### Author:  [@buzic](https://forum.qiime2.org/u/buzic)
#### Post date: [June 6, 2025, 11:42am UTC](https://forum.qiime2.org/t/maarjam-database/33257/2 "2025-06-06T11:42:45Z")
Hi @Salma_Sarker
You can download the MaarjAM databases in QIIME2-compatible formats from [here](https://maarjam.ut.ee/?action=bDownload). After downloading, you'll need to import the sequences and taxonomy files into QIIME2, then train a classifier. Your commands will look something like this:
```bash
qiime tools import \
--type 'FeatureData[Sequence]' \
--input-path maarjam_database_SSU_TYPE.qiime.fasta \
--output-path /maarjam-seqs.qza
qiime tools import \
--type 'FeatureData[Taxonomy]' \
--input-format HeaderlessTSVTaxonomyFormat \
--input-path maarjam_database_SSU_TYPE.qiime.txt \
--output-path maarjam-taxonomy.qza
qiime feature-classifier fit-classifier-naive-bayes \
--i-reference-reads maarjam-seqs.qza \
--i-reference-taxonomy maarjam-taxonomy.qza \
--o-classifier maarjam-classifier.qza
```
I tried using this database once for a test sequencing run, but ran into some issues with the primers, so I didn’t get very far. Still, I hope this is helpful for you!
all the best!
---
### Author:  [@Salma\_Sarker](https://forum.qiime2.org/u/Salma_Sarker)
#### Post date: [June 6, 2025, 12:54pm UTC](https://forum.qiime2.org/t/maarjam-database/33257/3 "2025-06-06T12:54:14Z")
Hi @buzic
Thank you so much for your help.
I’ve followed your instructions and it seems everything worked well. I was able to assign taxonomy to about 28K features using the **18S rDNA QIIME release (2021)** from MaarjAM. While no species-level assignments came through (only up to genus level), everything else looks perfect.
However, one thing that’s been bothering me is the speed— **the entire taxonomy assignment step finished within a minute** , which felt unusually fast. Below are the exact commands I used:
```auto
# Step 1: Import reference sequences and taxonomy
qiime tools import \
--type 'FeatureData[Sequence]' \
--input-path maarjam_database_SSU.qiime.fasta \
--output-path maarjam_seqs.qza
qiime tools import \
--type 'FeatureData[Taxonomy]' \
--input-path maarjam_database_SSU.qiime.txt \
--input-format HeaderlessTSVTaxonomyFormat \
--output-path maarjam_taxonomy.qza
```
I then trained the classifier and used `classify-sklearn` to assign taxonomy.
Let me know if this quick run-time is expected or if I might have missed something.
---
### Author:  [@colinbrislawn](https://forum.qiime2.org/u/colinbrislawn)
#### Post date: [June 6, 2025, 3:51pm UTC](https://forum.qiime2.org/t/maarjam-database/33257/4 "2025-06-06T15:51:02Z")
> [@Salma\_Sarker](#):
>
> Let me know if this quick run-time is expected or if I might have missed something.
This fast run time is possible if both the database and the test data is small / low complexity, and this databases is small! 🤏
Zooming out a little, every Qiime2 command _should_ tell you if it fails. I also inspect the output files with [view.qiime2.org](http://view.qiime2.org) to see more information about how the command ran.