Welcome to Sinorhizobium meliloti

Introduction

Sinorhizobium meliloti is a well-studied soil-dwelling bacterium that forms beneficial symbiotic associations with leguminous plants. Despite its importance, our knowledge of small open reading frame (sORF)-encoded proteins (SEPs) in S. meliloti is limited due to the difficulty in annotating and detecting these small but potentially significant molecules. However, recent advances in ribosome profiling (Ribo-seq) have enabled us to detect translated sORFs with high sensitivity.

In this study, we established a Ribo-seq procedure for S. meliloti 2011 and detected translation for 60% of the annotated coding sequences during growth in minimal medium. Using advanced computational tools and manual curation, we predicted the translation of 37 non-annotated sORFs with high confidence. To validate our findings, we supplemented our Ribo-seq data with mass spectrometry (MS) analyses from multiple sample preparation approaches and proteogenomic search databases.

Our integrated approach confirmed the existence of 47 annotated SEPs and identified 11 additional novel SEPs, expanding the small proteome of S. meliloti by 48 new molecules. Importantly, several of these novel SEPs are part of predicted operons and are conserved across related bacterial species, suggesting potential physiological functions. Our study showcases the power of combining Ribo-seq and MS approaches to discover novel SEPs and expand our understanding of bacterial physiology. These findings have important implications for future research into the biology of S. meliloti and related bacteria.

Publication

The publication describing this project can be accessed via the following DOI: https://doi.org/10.1093/femsml/uqad012

Data availability

The raw sequencing data used in this study can be accessed via the GEO accession number GSE206492.

The Mass spectrometry data is available on ProteomeXchange: PXD034931.

The iPtgxDBs can be downloaded from https://iptgxdb.expasy.org/.

The processed files used in this JBrowse2 genome browser can be downloaded here.

JBrowse2

Access Area

Default session

Annotation tracks

We provide multiple annotation tracks for the S. meliloti genome.
All annotation files can be loaded and unloaded using their respective check box in the track selector.
Annotation files are indexed and specific genes can be searched by gene name, locus tag or gene id using the search box in the top center of the JBrowse2 instance.
This JBrowse2 instance includes:

Track Description
The Reference Annotation The reference annotation for Haloferax volcanii
DeepRibo Predictions A list of ORF predictions created using the tool DeepRibo.
List of novel sORFs A list of 47 novel sORFs identified by Ribo-seq.
Start Codon Motifs All ATG motifs for the reference genome.
Alternative Start Codon Motifs All GTG and TTG motifs for the reference genome.
Stop Codon Motifs All TAA, TAG and TGA motifs for the reference genome.

Coverage tracks

Coverage tracks show the normalized read counts per nucleotide position. There are multiple mapping types used (threeprime/fiveprime/global). The mapping method of each file is marked in their description.

Shareable Links

JBrowse2 allows you to easily share observations with your colleagues and collaborators.
Using the "share"-button next to the session name, you can automatically generate a link. Anyone that uses this link will see the exact session you are currently looking at. This includes colors, zoom level, scale, loaded tracks etc...
This is a very powerful tool for sharing potential discoveries.

JBrowse2 user guide

For more information on how to use JBrowse2, please have a look at the comprehensive user guide provided by the JBrowse team. The chapter on basic usage is highly recommended to get familiar with the JBrowse2 interface.

Contributors

This project is a collaboration between the universities of Giessen, Würzburg, Greifswald, Freiburg and the Swiss Intitute of Bioinformatics.

AG Evguenieva-Hackenberg
  • Apl. Prof. Dr. Elena Evguenieva-Hackenberg
  • Robina Scheuer
  • Saina Azarderakhsh
  • Susanne Barth-Weber
AG Becher
  • Prof. Dr. Dörte Becher
  • Dr. Sandra Maaß
  • Jürgen Bartel
AG Ahrens
  • Dr. Christian H. Ahrens
  • Benjamin Heiniger
AG Sharma
  • Prof. Cynthia Sharma
  • Dr. Lydia Hadjeras
AG Backofen
  • Prof. Rolf Backofen
  • Rick Gelhausen

References