ABSTRACT
A strain was isolated from tobacco phylloplane and preliminarily identified as Pseudomonas fluorescens TL-1, which had the visible inhibition against ten plant pathogenic fungi, viz., Curvularia lunata, Bipolaris maydis, Valsa mali, Rhizoctonia solani, Colletotrichum gloeosporioides, Sclerotinia sclerotiorum, Botrytis cinerea, Alternaria alternate, Fusarium oxysporum and Verticillium dahlia in dual culture experiments. The ethyl acetate extract of nutrient broth seeded with Pseudomonas fluorescens TL-1 suspension was separated into fifty-nine fractions by the Sephadex LH-20 column and the antifungal activity of each fraction was tested with paper disc diffusion method against Curvularia lunata. The results showed that fraction 1 to 3 had the strongest inhibitory effects on Curvularia lunata. Furthermore, GC/MS analysis of the constituents of fraction 1 to 59 confirmed that phenol, 2, 4-bis (1, 1-dimethylethyl) was the active compound for the antifungal activity from Pseudomonas fluorescens TL-1.