AUTHOR=Zhou Jinwei , Bi Shiyuan , Chen Hongjuan , Chen Tongtong , Yang Rui , Li Minghui , Fu Yonghong , Jia Ai-Qun 

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

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00769

DOI=10.3389/fmicb.2017.00769

ISSN=1664-302X

ABSTRACT=<p>This study reported the efficacy of the metabolites of <italic>Plectosphaerella cucumerina</italic>, one phyllosphere fungus from <italic>Orychophragmus violaceus</italic>, against <italic>Pseudomonas aeruginosa</italic> quorum sensing (QS) and QS-regulated biofilms. The minimum inhibitory concentration (MIC) of the ethyl acetate (EtOAc) extract from <italic>P. cucumerina</italic> against <italic>P. aeruginosa</italic> PAO1 was 1.25 mg mL<sup>−1</sup>. At sub-MIC concentrations, <italic>P. cucumerina</italic> extract (0.25–1 mg mL<sup>−1</sup>) not only inhibited biofilm formation but also disrupted preformed biofilms of <italic>P. aeruginosa</italic> PAO1 without affecting its growth. Fluorescence and scanning electron microscope (SEM) showed architectural disruption of the biofilms when treated with <italic>P. cucumerina</italic> metabolites. Further investigation demonstrated that metabolites in <italic>P. cucumerina</italic> 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 <italic>P. cucumerina</italic> from the phyllosphere of <italic>O. violaceus</italic> and (2) anti-biofilm, antivirulence, and biofilm disruption activities of this fungus. Thus, this study provides fascinating new pathways for screening antipathogenic agents.</p>