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phyloFlash is a pipeline to rapidly reconstruct the SSU rRNAs and explore phylogenetic composition of an Illumina (meta)genomic or transcriptomic dataset.

This manual explains how to install and use phyloFlash. Navigate from the menu bar above or the table of contents below.

What does phyloFlash do?

  • Summarize taxonomic diversity of a metagenome/transcriptome library from SSU rRNA read affiliations
  • Assemble/reconstruct full-length SSU rRNA sequences suitable for phylogenetic analysis
  • Quick comparison of multiple samples by their taxonomic composition using a heatmap

You may read more about the pipeline design and application in our paper.

Quick-start

Download via Conda

We recommend installing phyloFlash and its dependencies using Conda or Mamba. Conda is a package manager that will also install dependencies that are required if you don’t have them already.

phyloFlash is distributed through the Bioconda channel on Conda.

According to the Conda documentation, avoid installing new packages to your base environment but create new environments for them as required. Also, specify all desired packages at the same time when creating a new environment, instead of adding them sequentially, to avoid dependency conflicts.

We also suggest using Mamba as a drop-in substitute for Conda. It implements a more effective dependency solver and is also the default Conda frontend for the pipeline manager Snakemake. Simply replace conda with mamba in the commands below. Note that the defaults channel should be enabled.

# If you haven't set up Bioconda already
conda config --add channels defaults
conda config --add channels bioconda
conda config --add channels conda-forge
# Try the following step if "solving environment" does not terminate
conda config --set channel_priority strict
# Create new environment named "pf" with phyloflash
conda create -n pf phyloflash
# Activate environment
conda activate pf
# Check that dependencies all installed properly
phyloFlash.pl -check_env

Download pre-formatted database

Pre-formatted databases derived from SILVA releases 138 onwards are available from the following Zenodo archives:

Download, checksum, and unpack:

wget https://zenodo.org/record/7892522/files/138.1.tar.gz # 5.5 GB download
tar -xzf 138.1.tar.gz # unpacks folder 138.1/ in the current location

Specify path to the database folder with the option -dbhome when running phyloFlash (see below).

Older versions of the SILVA database have a more restrictive license, so we are unable to distribute pre-formatted versions. You will have to download the original SILVA files and run the phyloFlash_makedb.pl script yourself (see Manual).

Test phyloFlash with test dataset

Test data are included with phyloFlash. The following assumes that you installed phyloFlash to a Conda environment called pf, and that the database files have been unpacked to a folder /path/to/138.1. By default, phyloFlash will look for the database folder in the folder where it is installed. If it is located somewhere else, specify this to the -dbhome option.

conda activate pf # If Conda environment not already activated
phyloFlash.pl -dbhome /path/to/138.1 -lib TEST -CPUs 16 \
 -read1 ${CONDA_PREFIX}/lib/phyloFlash/test_files/test_F.fq.gz \
 -read2 ${CONDA_PREFIX}/lib/phyloFlash/test_files/test_R.fq.gz \
 -almosteverything

Example phyloFlash commands

# Run with test data and 16 processors (default is to use all processors available)
phyloFlash.pl -lib TEST -CPUs 16 -read1 test_files/test_F.fq.gz -read2 test_files/test_R.fq.gz

# Run with interleaved reads
phyloFlash.pl -lib LIB -read1 reads_FR.fq.gz -interleaved

# Additionally run EMIRGE for 16S rRNA sequence reconstruction
phyloFlash.pl -lib LIB -emirge -read1 reads_F.fq.gz -read2 reads_R.fq.gz

# Compress output into tar.gz archive and write a log file
phyloFlash.pl -lib LIB -zip -log -read1 reads_F.fq.gz -read2 reads_R.fq.gz

# Run both SPAdes and EMIRGE and produce all optional outputs
phyloFlash.pl -lib LIB -everything -read1 reads_F.fq.gz -read2 reads_R.fq.gz

# Run SPAdes (skip EMIRGE) and produce all optional outputs (recommended)
phyloFlash.pl -lib LIB -almosteverything -read1 reads_F.fq.gz -read2 reads_R.fq.gz

# Supply trusted contigs containing SSU rRNA sequences to screen vs reads
phyloFlash.pl -lib LIB -read1 reads_F.fq.gz -read2 reads_R.fq.gz -trusted contigs.fasta

# Use SortMeRNA instead of BBmap for initial mapping (slower, but more sensitive)
phyloFlash.pl -lib LIB -read1 reads_F.fq.gz -read2 reads_R.fq.gz -sortmerna

Use the -help option to display a brief help and the -man option to display the full help message.

Use the -sc switch for MDA datasets (single cell) or other hard to assemble read sets.

Use the -zip switch to compress output files into tar.gz archive, and -log to save run messages to a log file

Example phyloFlash report from the provided test data can be viewed here.

Contents

About

phyloFlash is written by Harald Gruber-Vodicka (Google Scholar, GitHub), Elmar A. Pruesse (Google Scholar, GitHub), and Brandon Seah (Google Scholar, GitHub)

You can find the source code for phyloFlash at GitHub: HRGV/phyloFlash

Max Planck Institute for Marine Microbiology

Citation

If you use phyloFlash for a publication, please cite our paper in mSystems:

Harald R Gruber-Vodicka, Brandon KB Seah, Elmar Pruesse. phyloFlash: Rapid SSU rRNA profiling and targeted assembly from metagenomes. mSystems 5 : e00920-20; doi:10.1128/mSystems.00920-20

and also remember to cite the dependencies used, which are listed in each phyloFlash report file.