Curcumin from Curcuma longa affects the virulence of Pectobacterium wasabiae and P. carotovorum subsp. carotovorum via quorum sensing regulation

Abstract

In plant soft-rotting bacteria Pectobacterium, quorum sensing (QS) regulates the secretion of an arsenal of plant cell wall degrading extracellular enzymes (PCWDEs) and flagella-mediated motility via two different signaling molecules such as 3-oxohexanoyl-Lhomoserine lactone (3-oxo-C6-AHL) and 3-oxooctanoyl-L-homoserine lactone (3-oxo-C8-AHL). In the present investigation, the phytochemical compound curcumin was assessed for its QS inhibitory potential against AHL-dependent PCWDEs production and motility in P. wasabiae SCC3193, P. carotovorum subsp. Carotovorum Pcc21 and P. carotovorum subsp. Carotovorum Pcc. Interestingly, curcumin at sub-MIC effectively inhibited the production of PCWDEs as well as the swimming and swarming motility of all tested pathogens in a non-bactericidal fashion. Subsequently, the in vitro root pathogenicity assay in Arabidopsis thaliana unveiled the rescuing efficacy of curcumin against the pathogenicity of tested plant pathogens by attenuating its QS mediated virulence factors production. Besides, studies with QS mutant strain Pcc21-M10 also evidenced the QSI property of curcumin.

Phloretin, an Apple Phytoalexin, Affects the Virulence and Fitness of Pectobacterium brasiliense by Interfering With Quorum-Sensing

“…They were also congruent with reports on the inhibition of virulence in P. aeruginosa by different flavonoids (Paczkowski et al, 2017). In the last decade, a number of publications have confirmed the involvement of plant extracts and more specifically, plant-derived phenolics including salicylic acid, carvacrol, eugenol, rosmarinic acid, curcumin and others in QS interference and the reduction of bacterial virulence (Adonizio et al, 2006;Annapoorani et al, 2012;Joshi et al, 2016a,b;Sivaranjani et al, 2016;Fernandez et al, 2018). As many natural compounds hold toxicity toward bacterial cells, it is not always straightforward to separate between different modes of action.…”

“…The swimming-motility assays were performed according to the method described by Sivaranjani et al (2016). In the swimming assay, cultures grown for 16 h, 28 • C, of the test bacterial pathogens were treated with phloretin (0, 0.1, 0.2, and 0.4 mM) or ciprofloxacin 5 ng/ml and stab-inoculated into the center of the medium containing 1% tryptone, 0.5% NaCl and 0.3% agar.…”

High-Throughput, Quantitative Screening of Quorum-Sensing Inhibitors Based on a Bacterial Biosensor

“…Strains used for the screening of QQ bacteria were isolated from soil samples with the in situ trap cultivation method , and grown in LB medium at 28 °C. Swarming medium (5 g/L Difco Bacto agar, 8 g/L Difco nutrient broth, and 5 g/L glucose) and swimming medium (3 g/L Difco Bacto agar, 5 g/L NaCl, and 10 g/L tryptone) were used for motility assays. , Pectate lyase medium [10 g/L polygalacturonic acid, 10 g/L yeast extract, 0.38 μM CaCl 2 , 100 mM Tris-HCl (pH 8.5), 2 g/L sodium azide, and 8 g/L agarose], polygalacturonase medium [10 g/L polygalacturonic acid, 10 g/L yeast extract, 2.2 mM EDTA, 110 mM sodium acetate (pH 5.5), 2 g/L sodium azide, and 8 g/L agarose], and cellulase medium [1 g/L carboxymethyl cellulose, 25 mM sodium phosphate (pH 7.0), 2 g/L sodium azide, and 8 g/L agarose] were used . Antibiotics were used at the following concentrations: kanamycin, 50 μg/mL; gentamicin, 30 μg/mL; ampicillin, 50 μg/mL; chloramphenicol, 20 μg/mL; tetracycline, 15 μg/mL.…”

The New Antibacterial Properties of the Plants: Quo vadis Studies of Anti-virulence Phytochemicals?

“…Several anti-virulence phytochemicals have been shown to reduce establishment and damage caused by bacteria in vivo, mainly in the nematode Caenorhabditis elegans in murine models (Castillo-Juárez et al, 2015) and animals of importance in aquaculture (Zhao et al, 2015). Also, they have preventive effects on phytopathogenic bacterial infections in some models with Arabidopsis thaliana, Brassica oleracea and Solanum tuberosum, among others (Jhosi et al, 2015;Sivaranjani et al, 2016). Although there is evidence that disruption of virulence by phytochemicals is a potential strategy to prevent disease, there are emerging issues and challenges that have been little studied and are detailed below (Mulat et al, 2019).…”