Efficacy assessment of Pantoea jilinensis D25 fermentation broth against Botrytis cinerea

Abstract Tomato gray mold, caused by Botrytis cinerea, is one of the most devastating diseases affecting tomato plants. In this study, Pantoea jilinensis D25 fermentation broth (PJFB) was used to inhibit B. cinerea growth. The optimum fermentation time was 7 days. PJFB antifungal activity decreased when PJFB was heated to ≥60°C, whereas it was the strongest at pH 8. Moreover, ultraviolet treatment for a long time reduced its antifungal effect. PJFB, applied at 10 % (v/v), could inhibit B. cinerea growth by inhibiting its mycelial diameter, conidial production, and mycelial dry weight with the inhibition rates of 57.3 %, 51.2 %, and 78.6 %, respectively. PJFB could also increase conductivity and malondialdehyde (MDA) content in B. cinerea. Furthermore, PJFB inhibited B. cinerea on not only the leaf tissues but also the seedlings of tomato. The secondary metabolites in PJFB were determined through gas chromatography–mass spectrometry. Through laboratory toxicity analysis, we found that the major compounds in PJFB were 1,2-benzenedicarboxylic acid bis(2-methylpropyl) ester (14.3098 %), 2,4-di-tert-butylphenol (3.8036 %), 2,6,10,14-tetramethyl pentadecane (2.9947 %), and 1,3-dimethyl naphthalene (1.8586 %).