ARS | Publication request: A PHYTOTOXIC METABOLITE PRODUCED BY STILBOTHAMNIUM TOGOENSE

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 16, 2000
Publication Date: N/A

Technical Abstract: Stilbothamnium togoense (Henn.) is found in equatorial rainforests on seeds of rotting fruits and is believed to be an ancestral form of the Aspergillus flavus group. These tropical fungi are characterized by their greenish or golden yellow radiate conidial heads and by their large, simple or branched synnemata and stipitate or sessile sclerotia. The fungus was grown on rice and incubated for 21 days at 25 C. The fermented rice was extracted with methanol:water. Directed fractionation on solid phase C18 column gave an active fraction in the methanol eluate. This product was phytotoxic to duckweed (Lemna minor L.) at 590 ug/ml with a 40% reduction in frond growth with chlorosis of the fronds. IR and UV analyses of the phytotoxic product(s) indicates an aromatic or polyconjugated system as it emits fluorescence under long UV. Electro spray MS in the Atmosphere Positive Chemical Ionization (APCI) mode indicates a molecular weight of 636.