PURIFICATION OF AN ANTIBIOTIC EFFECTIVE AGAINST GAEUMANNOMYCES-GRAMINIS VAR TRITICI PRODUCED BY A BIOCONTROL AGENT, PSEUDOMONAS-AUREOFACIENS

Inhibition of the fungus that causes take-all of wheat, Gaeumannomyces graminis (Sacc.) Arx and Oliver var. tritici Walker, by a biocontrol agent, Pseudomonas aureofaciens Q2-87, was demonstrated both in vitro and in vivo. Q2-87 was originally isolated from the rhizosphere of wheat grown in a take-all suppressive soil. An antifungal compound was isolated from a chemically-defined broth culture of strain Q2-87. The structure of the compound was established to be 1,3,6-trihydroxy-2,4-diacetophenone through infrared, [H-1]nuclear magnetic resonance (NMR), [C-13]NMR, u.v., and high-resolution fast-atom bombardment (FAB) mass spectrometry. The synthesized product of the proposed structure demonstrated activity equal to the purified natural product.