Biosynthesis of Protoilludene Sesquiterpene Aryl Esters by Siberian Strains of the Genus Armillaria Fungi

Abstract

Secondary metabolites of the basidiomycetes of Armillaria borealis Marxm. and Korhonen, A. cepistipes Velen., A. gallica Marxm., A. ostoyae (Romagn.) Herink, and A. sinapina Bérubé and Dessur isolated in Southern Siberia (Krasnoyarsk region and Tyva Republic) and in the Far East (Sikhote-Alin) were studied. Metabolites belonging to the class of protoilludene sesquiterpene aryl esters of the melleolides group have been identified in the species A. borealis, A. cepistipes, and A. sinapina. The strains differ in the spectrum of synthesized melleolides. A. borealis strain 74g synthesized a wider range of melleolides than other strains of the species: melleolides B, C, D and H, melledonals B and C, 5'-O-methylmelledonal, 13-hydroxy-5'-O-methylmelledonal, and armillarinin. It was shown that the composition of the medium influenced the amount of synthesized metabolites. All of the studied strains synthesizing melleolides exhibited a toxicogenic and phytopathogenic effect on seeds and seedlings of Picea abies (L.) H. Karst. and Abies sibirica Ledeb. A significant decrease in seed germination energy, laboratory and ground seed germination, the development of the root system of conifer seedlings was revealed. The maximum inhibitory effect was shown by the culture fluid of A. borealis 74g with the greatest amounts and variety of melleolides in the metabolome profile.