THE STRUCTURE AND BIOLOGICAL PROPERTIES OF SECONDARY METABOLITES PRODUCED BY PELTASTER FRUCTICOLA, A FUNGUS ASSOCIATED WITH APPLE SOOTY BLOTCH DISEASE

Peltaster fructicola, one of the fungi that cause sooty blotch of appl e (Malus X domestica) fruit, produced four metabolites in liquid cultu re that were isolated and structurally identified as trichothecolone, trichothecolone acetate, 6-methylsalicylic acid, and 2,5-dihydroxybenz oic acid. These toxins were not detected in a culture of Leptodontidiu m elatius, another fungus associated with apple sooty blotch. The four toxins were nonspecific; they caused necrosis when spotted on differe nt cultivars or strains of apple and on eight weed species. In additio n, trichothecolone acetate and 6-methylsalicylic acid showed strong an tifungal properties against Botryosphaeria dothidea, B. obtusa, Collet otrichum gloeosporioides, and C. acutatum in vitro. Prior treatment of fruit with 6-methylsalicylic acid reduced infection of fruit inoculat ed with C. acutatum.