Anti-Biofilm and Antivirulence Activities of Metabolites from Plectosphaerella cucumerina against Pseudomonas aeruginosa

Abstract

This study reported the efficacy of the metabolites of Plectosphaerella cucumerina, one phyllosphere fungus from Orychophragmus violaceus, against Pseudomonas aeruginosa quorum sensing (QS) and QS-regulated biofilms. The minimum inhibitory concentration (MIC) of the ethyl acetate (EtOAc) extract from P. cucumerina against P. aeruginosa PAO1 was 1.25 mg mL−1. At sub-MIC concentrations, P. cucumerina extract (0.25–1 mg mL−1) not only inhibited biofilm formation but also disrupted preformed biofilms of P. aeruginosa PAO1 without affecting its growth. Fluorescence and scanning electron microscope (SEM) showed architectural disruption of the biofilms when treated with P. cucumerina metabolites. Further investigation demonstrated that metabolites in P. cucumerina attenuated the QS-dependent virulence factors. LC-MS/MS spectra coupled with experimentally standard samples suggested that patulin and emodin might act as the principal components possessing anti-biofilm and antivirulence activities. This is the first report of (1) the isolation of P. cucumerina from the phyllosphere of O. violaceus and (2) anti-biofilm, antivirulence, and biofilm disruption activities of this fungus. Thus, this study provides fascinating new pathways for screening antipathogenic agents.

The ability of plants to produce strigolactones affects rhizosphere community composition of fungi but not bacteria

“…This species of filamentous fungus can thrive on plant debris as free-living saprophytes; but can also be pathogenic to a range of plant species including Arabidopsis thaliana, tomato, and other horticultural crops (Alam et al, 2017;Carlucci et al, 2012). Interestingly, P. cucumerina has also been isolated from healthy leaves of Orychophragmus violaceus, an edible medicinal plant from China (Zhou et al, 2017). Furthermore, extracts of this fungus supress the formation and disrupt bacterial biofilms (Zhou et al, 2017).…”

“…Interestingly, P. cucumerina has also been isolated from healthy leaves of Orychophragmus violaceus, an edible medicinal plant from China (Zhou et al, 2017). Furthermore, extracts of this fungus supress the formation and disrupt bacterial biofilms (Zhou et al, 2017). Intriguingly, four P. cucumerina were shown to have different abundances in rhizospheres of max4 compared to the wild-type plants.…”

Growth inhibition and metabolomic analysis of Xanthomonas oryzae pv. oryzae treated with resveratrol

“…MICs of compounds (1-9) were determined by following the two-fold dilution method [38]. In brief, overnight cultures of Xoo (1%, v/v) were resuspended in fresh nutrient agar (NB) medium in the presence of the samples (0.001-0.1 mg/mL for compounds (1-6) and 0.01-1 mg/mL for compounds (7-9)) in 96-well plates, then incubated at 28 °C and 180 rpm for 18 h. The MICs of compounds (1)(2)(3)(4)(5)(6)(7)(8)(9) against Xoo are shown in Table 1.…”

Resveratrol inhibits the growth of Xanthomonas oryzae pv. oryzae and the metabolomic analysis

“…MICs of compounds (1-9) were determined by following the two-fold dilution method [36]. In brief, overnight cultures of Xoo (1%, v/v) were resuspended in fresh nutrient agar (NB) medium in the presence of the samples (0.001-0.1 mg/mL for compounds (1-6) and 0.01-1 mg/mL for compounds (7-9)) in 96-well plates, then incubated at 28 °C and 180 rpm for 18 h. The MICs of compounds (1)(2)(3)(4)(5)(6)(7)(8)(9) against Xoo are shown in Table 1.…”