In vitro tolerance to antifungal glycoalkaloids and biofilm forming ability of the antagonistic yeast Meyerozyma guilliermondii strain SQUCC-33Y

Meyerozyma guilliermondii strain SQUCC-33Y is an antagonistic yeast against Alternaria alternata , the tomato fruit rot pathogen. In a previous study, we demonstrated the potential of M. guilliermondii SQUCC-33Y in the control of A. alternata -induced postharvest fruit rot of tomato. In this study, M. guilliermondii SQUCC-33Y was evaluated for its ability to tolerate antifungal glycoalkaloids of tomato and to form biofilm under in vitro conditions. Glycoalkaloids were extracted from immature green tomato fruits. Electrospray ionization-mass spectrometry (ESI-MS) analysis showed the presence of α-tomatine, β-tomatine, tomatidine, lycoperoside A, lycoperoside H, coumaric acid and sinapic acid in the glycoalkaloids extract. In vitro antifungal assays showed that M. guilliermondii SQUCC-33Y and A. alternata were tolerant to glycoalkaloids of tomato, while Rhizoctonia solani was sensitive. M. guilliermondii SQUCC-33Y was able to form biofilm as determined by in vitro microtiter plate assay.