A resveratrol oligomer, hopeaphenol suppresses virulence activity of Pectobacterium atrosepticum via the modulation of the master regulator, FlhDC

Abstract

Pectobacterium atrosepticum (P. atrosepticum: Pba) which causes potato soft rot and blackleg is a notorious plant pathogen worldwide. Discovery of new types of antimicrobial chemicals that target specifically to virulence factors such as bacterial motility and extracellular enzymes is required for protecting crops from pathogenic infection. A transcriptomic analysis of Pba upon hopeaphenol treatment revealed that bacterial motility-related gene expression, including a master regulator flhDC genes, was significantly influenced by hopeaphenol. We further generated a double knock-out mutant of flhDC genes by CRISPR/Cas9 system and confirmed phenotypic changes in bacterial motility, transcription of extracellular enzymes, and disease development consistent with the result of wild-type treated with hopeaphenol. The hopeaphenol-treated Pba strains, wild-type, double mutant, and complemented strain were unable to secrete the enzymes in vitro, while ΔflhDC double mutant strain reduced the secretion. Thus, our study supports that FlhDC is essential for the virulence of Pba, and proposes that hopeaphenol modulates FlhDC-dependent virulence pathways, suggesting a potential of hopeaphenol as an anti-virulence agent to manage potato soft rot and blackleg diseases.

Journey to the center of the phage; revealing the ejectosome of Pectobacterium bacteriophage ΦM1

“…The host bacterium for ΦM1, P. atrosepticum, is a globalGram-negative potato pathogen found in both temperate and tropical regions, and is known to colonize the intercellular spaces of plant cells and degrade the cell wall, causing blackleg disease and aerial stem rot (22,23). Recent studies have focused on identifying biocontrol agents against P. atrosepticum, including antimicrobial chemicals, zinc/silver nanoparticles, and antagonistic bacterial isolates (24)(25)(26)(27). Comparatively little research has been done on the potential of phage-based biocontrols.…”

A natural cyclic peptide valinomycin enhances plant innate immunity

“…With these aims, natural compounds inducing plant resistance have been widely identified, including β-aminobutyric acid, resveratrol oligomers, and bacterial PAMPs (Cohen et al, 2016;Zipfel et al, 2004). Moreover, various plant-derived natural compounds, including hopeaphenol, were identified as anti-virulence agents against pathogens (Kang, Hwang, et al, 2022;Silva et al, 2016).…”

“…However, antibiotic resistance emerged as a major concern as pesticides gradually lost their efficacy. Thus, new research directions focusing on enhancing plant immunity and suppressing pathogen virulence have been proposed as promising alternatives (Dickey et al, 2017; Kang et al, 2022). With these aims, natural compounds inducing plant resistance have been widely identified, including β-aminobutyric acid, resveratrol oligomers, and bacterial PAMPs (Cohen et al, 2016; Kang et al, 2022; Zipfel et al, 2004).…”

“…Thus, new research directions focusing on enhancing plant immunity and suppressing pathogen virulence have been proposed as promising alternatives (Dickey et al, 2017; Kang et al, 2022). With these aims, natural compounds inducing plant resistance have been widely identified, including β-aminobutyric acid, resveratrol oligomers, and bacterial PAMPs (Cohen et al, 2016; Kang et al, 2022; Zipfel et al, 2004). Moreover, various plant-derived natural compounds, including hopeaphenol, were identified as anti-virulence agents against pathogens (Kang, Hwang, et al, 2022; Silva et al, 2016).…”