P-163 - Friend or foe? Comparative Multi‐Omics to dissect the role of Pseudomonas GacS/GacA in the evolutionary transition from phytopathogen to mutualist

Monday, July 14, 2025

13:30 - 15:15

Location: Confex Hall 3

Microbial infection strategies (pathogens & non-pathogens)

Presenting Author(s)

FM

Federico Matias Muzio

Univ of Pittsburgh
Pittsburgh, Pennsylvania, United States

Author(s)

AG

Alexandra D. Gates, PhD

Postdoctoral Researcher
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
AB

Aditi Bhat

Univ of Pittsburgh - Pittsburgh, PA
Pittsburgh, Pennsylvania, United States
CH

Cara Haney

University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Closely related bacteria in the genus Pseudomonas, including pathogens and mutualists, compete for host-associated nutrients and exhibit lifestyle-specific adaptations. Pseudomonas fluorescens subsp. brassicacearum includes both mutualists and pathogens of plants, serving as a model to study colonization and lifestyle-specific mechanisms. Through comparative genomics we revealed gain and loss of pathogenesis genes in closely related strains, suggesting lifestyle transitions can occur over short evolutionary timescales. We found the GacA/S two-component system is essential for expressing recently acquired genomic islands, indicating a swift GacA/S regulon divergence, which may influence bacterial lifestyle. To identify additional genes associated with beneficial and pathogenic lifestyles in closely related Pseudomonas, we are using comparative multi-omics on gacA mutants, with the objective of obtaining transcriptomic and metabolomic data to identify genes and molecules related to Pseudomonas lifestyle. We are using strains across the Pseudomonas genus that include both mutualists and pathogens of plants and performing metabolomics and transcriptomics on wild-type and gacA mutants. This will allow us to identify genes, pathways, and metabolites that are part of the conserved GacA/S regulon, or lifestyle specific. The integration of results will provide insights into the mechanisms that drive lifestyle transitions in plant-associated Pseudomonas.