Phytotoxins produced by the oak pathogen Discula quercina
Two phytotoxic metabolites, p-hydroxybenzaldehyde and indol-3-aldehyde, were isolated and identified by spectroscopic methods from solid cultures of Discula quercina, an endophytic fungal pathogen frequently associated with oak decline in Italy. In addition, the fungus produced an unusual acyclic keto acid as a major metabolite, which was identified by spectroscopic and chemical methods as 5-oxo-6E,8E-octadecadienoic acid. In leaf puncture assays on Quercus suber and Q. ilex leaves, indol-3-aldehyde proved to be more toxic than p-hydroxybenzaldehyde, while 5-oxo-6E,8E-octadecadienoic acid was inactive even at the highest concentration used (1 mg ml−1). Although indol-3-aldehyde is a known microbial metabolite, its phytotoxic activity has hitherto not been reported. This report is the first to describe the production of phytotoxic compounds by D. quercina.
Document Type: Research Article
Affiliations: 1: Dipartimento di Scienze del Suolo, della Pianta, dell’Ambiente e delle Produzioni Animali, Università di Napoli Federico II, Portici, Italy 2: Dipartimento di Protezione delle Piante-Sezione di Patologia vegetale, Università di Sassari, Via E. De Nicola, 07100 Sassari, Italy
Publication date: April 1, 2011