Root exudates protect rhizosphere Pseudomonas from water stress
Document Type
Article
Publication Date
9-1-2025
School
Biological, Environmental, and Earth Sciences
Abstract
Arid and semi-arid regions, which account for over 40% of global land area, are affected by fluctuations in temperatures and rainfall. In these environments, plants recruit beneficial rhizosphere microorganisms to mitigate stress and enhance survival. This study investigates the molecular mechanisms by which Pseudomonas synxantha 2-79, a rhizobacterium associated with wheat grown in arid regions, adapts to water stress through its interaction with root exudates. We found that water-stressed wheat root exudates contain elevated levels of choline and glycine betaine, which serve as osmoprotectants for 2-79. Exposure to these exudates upregulated genes involved in the uptake and catabolism of these quaternary ammonium compounds (QACs), enhancing the bacterium’s ability to cope with osmotic stress. Mutants lacking QAC transporters displayed reduced growth under osmotic stress, highlighting the importance of these pathways in rhizosphere competence. Furthermore, the study revealed that 2-79 also produces biofilms containing protective exopolysaccharides, such as alginate and Psl, which aid in stress resilience. Overall, our findings provide insights into how root exudates shape bacterial adaptation to the water-stressed rhizosphere and highlight the role of QAC metabolism and biofilm formation in microbial survival and plant-microbe interactions under drought conditions.
Publication Title
Applied and Environmental Microbiology
Volume
91
Issue
9
Recommended Citation
Bhattacharyya, A.,
Pablo, C.,
Mavrodi, O.,
Flynt, A.,
Weller, D.,
Thomashow, L.,
Mavrodi, D.
(2025). Root exudates protect rhizosphere Pseudomonas from water stress. Applied and Environmental Microbiology, 91(9).
Available at: https://aquila.usm.edu/fac_pubs/22164