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Diplodia corticola is one of the most aggressive fungal pathogens of Quercus species involved in the decline of Mediterranean oak forests. In this study, three strains of D. corticola associated with holm (Quercus ilex) and cork (Quercus suber) oak trees exhibiting dieback symptoms and cankers in Algeria were selected to investigate the production of secondary metabolites. Metabolomic analyses revealed the production of several known compounds, such as sphaeropsidins, diplopyrones and diplofuranones. Moreover, the comparative investigation of secondary metabolites produced by the analyzed strains with different degrees of virulence revealed possible implications of these compounds in the fungal virulence. In particular, sphaeropsidins seem to be the main phytotoxic compounds of D. corticola involved in the infections of Quercus species, with a possible synergistic influence of the less representative compounds in the fungal virulence. [ABSTRACT FROM AUTHOR]

Mitidjospirone, a new spiridioxynaphthalene, was isolated from the mycelial extract of a strain of Lasiodiplodia mitidjana, a recently described species belonging to the family Botryosphaeriaceae. Its structure was elucidated by extensive spectroscopic analysis and the absolute configuration was determined by electronic circular dichroism (ECD) experiment. Furthermore, several known compounds were identified during the screening of secondary metabolites produced by four strains of L. mitidjana. [ABSTRACT FROM AUTHOR]

An undescribed 5,6-dihydropyran-2-one, namely diplopyrone C, was isolated and characterized from the cultures of an isolate of the fungus Diplodia corticola recovered from Quercus suber in Algeria. The structure and relative stereostructure of (5S,6S,7Z,9S,10S)-5-hydroxy-6-(2-(3-methyloxiran-2-yl)vinyl)-5,6-dihydro-2H-pyran-2-one were assigned essentially based on NMR and MS data. Furthermore, ten known compounds were isolated and identified in the same cultures. The most abundant product, the tetracyclic pimarane diterpene sphaeropsidin A, was tested for insecticidal effects against the model sucking aphid, Acyrthosiphon pisum. Results showed a toxic dose-dependent oral activity of sphaeropsidin A, with an LC50 of 9.64 mM. [ABSTRACT FROM AUTHOR]