AUTHOR=Vallet Marine , Chong Yee-Meng , Tourneroche Anne , Genta-Jouve Grégory , Hubas Cédric , Lami Raphael , Gachon Claire M. M. , Klochkova Tatyana , Chan Kok-Gan , Prado Soizic 

TITLE=Novel α-Hydroxy γ-Butenolides of Kelp Endophytes Disrupt Bacterial Cell-to-Cell Signaling

JOURNAL=Frontiers in Marine Science

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2020.00601

DOI=10.3389/fmars.2020.00601

ISSN=2296-7745

ABSTRACT=<p>A wide range of microbial symbionts such as bacteria and fungi colonize the tissues of macrophytes. The chemical interactions between these endophytes remain underexplored. The obligate marine fungus <italic>Paradendryphiella salina</italic> was isolated from several healthy brown macrophyte species. Novel α-hydroxy γ-butenolides produced by <italic>P. salina</italic> were purified and characterized by nuclear magnetic resonance (NMR). These compounds interfere with the bacterial quorum sensing system as shown in bioassays with pathogenic bacterial model <italic>Pseudomonas aeruginosa</italic>. Ultra-performance liquid chromatography–high-resolution mass spectrometry (UHPLC-HRMS)-based comparative metabolomics revealed the presence of the main α-hydroxy γ-butenolides among all the <italic>P. salina</italic> strains isolated from different hosts as well as a high metabolic variability related to the alga-host species. Collectively, these findings highlight the key role of microbial chemical signaling that may occur within the algal holobiont.</p>