Disruptive effects of resveratrol on a bacterial pathogen of beans

Authors: Cooper, Bret

Submitted to: Journal of Proteome Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2022
Publication Date: 12/30/2022
Citation: Cooper, B. 2022. Disruptive effects of resveratrol on a bacterial pathogen of beans. Journal of Proteome Research. 22(1):204-214. https://doi.org/10.1021/acs.jproteome.2c00633.
DOI: https://doi.org/10.1021/acs.jproteome.2c00633

Interpretive Summary: Halo blight disease, caused by a bacterium, reduces harvests of the dry, edible common bean. Natural resistance genes in the bean plant can provide protection against some strains by producing phytoalexins, antibiotic compounds. One such phytoalexin that reduces bacterial replication is resveratrol. To learn more about the antibiotic properties of resveratrol, USDA-ARS scientists in Beltsville, Maryland, used mass spectrometry, an analytical technique, to measure the changes in proteins after bacteria were exposed to resveratrol. The results show that the bacterium is actively engaged in trying to eliminate resveratrol from cells and that resveratrol decreases enzymes the bacterium needs to produce energy and to move. Hence, the antibiotic properties of resveratrol include reducing bacterial energy needed for reproduction and slowing bacterial motility. These findings will be of interest to scientists in the government, at universities, and at private institutions who want to understand how beans and other plants resist pathogen infection.

Technical Abstract: Upon inoculation, common beans immune to Pseudomonas savastanoi pv. phaseolicola race 5 (R5) accumulate resveratrol, a phytoalexin. How resveratrol acts upon on this bacterium is not known, although resveratrol reduces ATPase activity, motility, quorum sensing, and biofilm formation in animal pathogenic bacteria in vitro. In this study, mass spectrometry was used to monitor the effects of resveratrol on a bean bacterial pathogen. R5 responded by producing multidrug efflux proteins to pump resveratrol out of cells. Other changes in R5 enzyme abundances were consistent with a slowed tricarboxylic acid cycle, the consequence of which likely impeded ATP production by oxidative phosphorylation. There also were enzymatic shifts consistent with decreased pools of GMP and AMP and decreased amounts of flagellar proteins. A motility assay in resveratrol confirmed a reduction in R5 flagellar movement, and mass spectrometry of metabolite extracts confirmed decreased pools of GMP and AMP. Mass spectrometry also detected the accumulation of a reactive aldehyde byproduct of resveratrol catabolism. Overall, the study reveals that resveratrol likely imparts its antibiotic activity during plant immunity by disturbing the bacterial tricarboxylic acid cycle, interfering with ATP biosynthesis at the electron transport chain, and by decreasing bacterial proteins needed for pathogenicity and leaf colonization.