Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 1998
Publication Date: N/A
Technical Abstract: Kenaf is a annual subtropical plant that is being evaluated as an alternative source of paper and pulp products. It is virtually immune to the fungal wilt pathogen, Verticillium dahliae. When kenaf is attacked by pathogens, it produces antibiotic compounds (i.e. phytoalexins) that are toxic to the pathogen. Two of these phytoalexins are hibiscanal and hibiscanone. Hibiscanal is weakly toxic to V. dahliae having an ED50 value of 25.8 ug/ml. However, hibiscanone, is an extremely active phytoalexin with an ED50 value of 1.2 ug/ml. To counter the effects of hibiscanone, V. dahliae reduces the phytoalexin to the less toxic hydroquinone. A third phytoalexin has recently been identified as 2,5-dimethyl-3-hydroxy-1,4-naphthoquinone. All of the phytoalexins are believed to be derived from farnesol diphosphate and are thus trinorsesquiterpenoids. The toxicities of these compounds, findings from 13C-acetate feeding studies to support their biosynthetic origin, and the structure of possible biosynthetic precursors will be presented.