Stagonolides G−I and Modiolide A, Nonenolides Produced by Stagonospora cirsii, a Potential Mycoherbicide for Cirsium arvense

• Published in: Journal of natural products (Washington, D.C.) D.C.), 2008-11, Vol.71 (11), p.1897-1901
• Main Authors: Evidente, Antonio, Cimmino, Alessio, Berestetskiy, Alexander, Andolfi, Anna, Motta, Andrea
• Format: Article
• Language: English
• Subjects: Ascomycota - chemistry; bioassays; biological control agents; chemical structure; chicory; Cichorium intybus; Cirsium - drug effects; Cirsium - growth & development; Cirsium arvense; Dose-Response Relationship, Drug; esters; Herbicides - chemistry; Herbicides - isolation & purification; Herbicides - pharmacology; heterocyclic compounds; Heterocyclic Compounds, 1-Ring - chemistry; Heterocyclic Compounds, 1-Ring - isolation & purification; Lactones - chemistry; Lactones - isolation & purification; modiolide; mycoherbicides; nonenolide; noxious weeds; phyllostictines; phyllostoxins; phytotoxicity; plant pathogenic fungi; seedlings; spectral analysis; stagonolide; Stagonospora; Stagonospora cirsii; weed control
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np800415w

Stagonospora cirsii Davis, a fungal pathogen isolated from Cirsium arvense (commonly called Canada thistle) and proposed as a potential mycoherbicide of this perennial noxious weed, produces phytotoxic metabolites in liquid and solid cultures. Stagonolide, the main phytotoxic metabolite, and five new related nonenolides, named stagonolides B−F, were isolated from the fungus. When grown on solid culture, nonenolide yields increased. A further four nonenolides were isolated and characterized by spectroscopy. Three were new compounds and named stagonolides G−I, and the fourth was identified as modiolide A, previously isolated from Paraphaeosphaeria sp., a fungus separated from the horse mussel. Leaf disk-puncture assays at 1 mg/mL of stagonolides H−I and modiolide A were phytotoxic to C. arvense. Only stagonolide H inhibited chicory seedling root growth. The most potent toxin, stagonolide H, indicated selectivity when tested on leaves of eight different plants: Canada thistle was most sensitive to the compound.