Role of 2-phenylethanol in regulating population density and biocontrol efficacy of Scheffersomyces spartinae W9 via quorum sensing.

The marine antagonistic yeast Scheffersomyces spartinae W9 can significantly control gray mold in strawberries caused by Botrytis cinerea. 2-Phenylethanol (2-PE), a quorum sensing molecule, is also a volatile organic compound secreted by S. spartinae W9. Herein, we investigated the role of 2-PE in regulating the population density and biocontrol efficacy of S. spartinae W9. The results showed that 2-PE significantly increased the population density and biofilm formation ability of S. spartinae W9, and further enhanced its stress tolerance. 2-PE significantly enhanced the ability of S. spartinae W9 to inhibit the mycelial growth and spore germination of B. cinerea, and also improved its biocontrol efficacy and colonization ability against gray mold on strawberries. Further analysis of the associated regulatory genes revealed that 2-PE significantly upregulated the expression of 2-PE biosynthesis-related genes including ARO8, ARO9, and ARO10, cell proliferation-related genes including CDC25, RNR2, and TDH1, biofilm formation-related genes including FLO8, ECM4_1, and ERG3, as well as stress tolerance-related genes GRE2_4, CYS3, and AOX2. These results provide a more comprehensive molecular explanation of how 2-PE acts as a quorum-sensing molecule to improve the population density and biocontrol efficacy of S. spartinae W9.