ARS | Publication request: PRODUCTION AND TOXICITY OF 2,3-DIHYDRO-5-HYDROXY-2-METHYL-4H-1-BENZOPYRAN-4-ONE BY PHIALPHORA GREGATA

Submitted to: Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 29, 1998
Publication Date: N/A

Interpretive Summary: Phialophora gregata is a vascular fungal pathogen of soybean. Although this fungal pathogen causes an important soybean disease, it is not known how the pathogen kills soybean plant cells. From ongoing work, it was found that this fungus produced an unknown metabolite when grown on sterile white rice. This metabolite was purified from rice cultures by standard chemical procedures. The structure of this metabolite was determined by a chemist and identified as 2,3-dihyro-5-hydroxy-2methyl-4H-1-benzopyran-4-one. In repeated laboratory tests it was found that this metabolite prevented callus formation on soybean hypocotyl tissue. This is the first time this metabolite has been shown to be produced by a Phialophora species of fungi and is toxic to soybean cells. This new information is of value to soybean plant pathologists and soybean physiologists because it identifies a new toxic metabolite produced by an important soybean fungal pathogen.

Technical Abstract: A metabolite, 2,3-dihydro-5-hydroxy-2-methyl-4H-1-benzopyran-4-one, was isolated from 3 week old rice cultures of Phialophora gregata, a soybean pathogen, grown at 25 percent. This material in repeated bioassays prevented callus formation on soybean hypocotyl sections at 100 and 200 microgram/ml callus culture medium. This is the first report of the production of this metabolite by a member of the Phialphora genus and of its toxicity to soybeans.