2017,    N 3 (29)    

MYCOLOGY

Pavlov I., Litovka Y., Litvinova E., Timofeev A., Pashenova N., Safronova I., Kulakov S., Mulyava V.V., Mulyava V.E.

Armillaria borealis Marxm. & Korhonen: distribution, phytopathogenicity and morphology

The northern distribution limit (58 °N) of Armillaria borealis in Siberia was first established. The maximum height of colonization of the substrate with the formation of fruit bodies reaches 950 m in the mountains of the Eastern Sayan. Siberian strains of A. borealis are phytopathogenic for coniferous and deciduous trees. Intraspecific heterogeneity in the degree of inhibition of test plants with artificial inoculation for three months has been proved. 33% of fungal cultures are characterized by a high speed of the mycelium fan propagation through the cambium Populus tremula and the formation of necrosis zones (35-75 mm) due to the synthesis of lignocellulase enzymes and secondary metabolites. 82% of the strains cause a massive post-emergence attack of the Abies sibirica seedlings due to the formation of a dense mycelium in the contact zone of the fungus with the root system. The radial growth rate of A. borealis on natural and synthetic media under laboratory conditions is 0.1-0.6 mm per day at 16-23 ° C. The main morphological and cultural differences are associated with the formation of rhizomorphs. Their maximum formation occurs on carrot agar at a temperature of 23 ° C. A decrease in temperature to 16 оС leads to an early laying of rhizomorphs on a natural substrate and their absence on a synthetic medium. No significant micromorphological differences were observed. All strains form generative septate hyphae with a width of 1.5-4 μm and skeletal dark-colored hyphae without septa up to 3.0 μm in width. Anastomoses irregular, clamp connection absent.

Keywords: ARMILLARIA BOREALIS, ROOT PATHOGENS, MORPHOLOGY, CULTURAL FEATURES, PHYTOPATHOGENICITY, FOREST DECLINE