Skip to main content
ISMPMI Congress 2025 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Poster

Session: Session 1 Presenting Authors at Posters (Odds)

P-323 - Hfq-mediated sRNA-mRNA pairing facilitates growth adaptation of Xylella fastidiosa to nutrient downshift through extracellular vesicles

Monday, July 14, 2025
13:30 - 15:15  
Location: Confex Hall 3
RNA on the move: Advances in Cross-Species communiation &Translational Research

The Gram-negative bacterial plant pathogen Xylella fastidiosa (Xf) poses a major threat to agriculture, causing severe diseases in economically important crops. To colonize plant hosts and spread via insect vectors, Xf transitions between planktonic and biofilm growth states. Here, we investigated the regulation of bacterial growth adaptation to the transition from a nutrient-rich to a nutrient-poor environment. A sudden nutrient downshift induces biofilm formation and triggers a transcriptomic response characterized by nutrient adjustments and quorum sensing signaling. We found that genetic deletion of the RNA chaperone Hfq reduces the transcriptional response to nutrient downshift, including reduced induction of transcriptional regulators, revealing Hfq as a key master regulator in this process. Xf ∆hfq cells are locked in biofilm mode, with altered morphology and reduced motility both in culture and in planta. Since Hfq facilitates base pairing between sRNAs and mRNAs, we performed sRNA-seq, identifying Hfq-associated sRNA candidates that regulate mRNAs involved in this adaptation. Furthermore, Hfq was found to be associated with extracellular vesicle (EV) membranes, whose production increased during sudden nutrient downshift, suggesting that Hfq mediates the nutrient downshift response in a contact-independent manner. Our findings provide insight into RNA silencing as a fundamental strategy of Xf to adapt to nutrient-poor environments such as xylem fluids.