Hfq mediates transcriptome-wide RNA structurome reprogramming under virulence-inducing conditions in a phytopathogen

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Messenger RNA (mRNA) structure is crucial for gene expression regulation.
• The specific roles of mRNA folding in plant bacterial pathogens are not well understood.
• Understanding these mechanisms can reveal new targets for controlling bacterial infections.

Purpose of the Study:

• To investigate the impact of nutritional conditions on mRNA structure in Pseudomonas syringae.
• To elucidate the mechanisms by which mRNA structure influences bacterial virulence.
• To identify key regulatory factors involved in mRNA structure-mediated gene expression.

Main Methods:

• Dimethyl sulfate sequencing (DMS-seq) was employed to map mRNA structures.
• Experiments were conducted under both nutrient-rich and nutrient-deficient (minimal medium) conditions.
• Gene expression analysis was performed to identify key regulatory proteins.

Main Results:

• Significant changes in mRNA structure were observed in minimal medium, impacting global translation efficiency (TE).
• The expression of the Hfq protein was found to increase under nutrient-deficient conditions.
• Transcription regulators RpoS and CysB were identified as direct activators of Hfq expression.

Conclusions:

• Nutritional stress induces significant mRNA structural changes in Pseudomonas syringae, leading to altered translation efficiency and increased virulence.
• The Hfq protein, regulated by RpoS and CysB, plays a central role in this mRNA-mediated regulatory pathway.
• The conserved nature of Hfq and its interaction with RpoS suggests a broadly important mechanism for RNA-based gene control and feedback loops in bacteria.