ISSN:
1432-072X
Keywords:
Degradation
;
Pterocarpan
;
Phytoalexins
;
Medicarpin
;
Ascochyta rabiei
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Four strains of Ascochyta rabiei pathogenic to chickpea (Cicer arietinum L.) were shown to efficiently degrade medicarpin (3-hydroxy-9-methoxypterocarpan), the main phytoalexin of this plant. Degradative studies were performed with mycelium preparations or with crude protein extracts of the fungus. Isolation and structural elucidation of 10 catabolites by chromatographic and spectroscopic techniques revealed that medicarpin degradation involves 1. reductive conversion to a 2′-hydroxyisoflavan, 2. O-demethylation, 3. aromatic hydroxylation in ring A and 4. formation of a 1a-hydroxy-pterocarp-1,4-diene-3-one. As terminal aromatic catabolite 2,4-dihydroxybenzoic acid was found. A catabolic sequence for medicarpin is postulated and the results are discussed with regard to pterocarpan dissimilation by other phytopathogenic fungi.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00415285
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