Phytotoxic metabolites of Phoma sorghina, a new foliar pathogen of pokeweed

Phoma sorghina is a newly described leaf spot pathogen on pokeweed. The fungus produced six Phytotoxins in liquid culture which were isolated and structurally identified as 6-methylsalicylic acid, epoxydon, desoxyepoxydon, phyllostine, 2,3′-dihydroxy-4-methoxy-5′,6-dimethyl diphenylether, and epoxydon 6-methylsalicylate ester. The cell-free culture filtrate and all six toxins caused necrosis when spotted on pokeweed leaves and eight other weed species thus all six toxins were nonspecific Phytotoxins. Epoxydon, desoxyepoxydon and the diphenylether showed strong antimicrobial properties against all bacteria and fungi tested. 6-Methylsalicylic acid, epoxydon and the diphenylether also inhibited sorghum root growth.