Woody plants in the oldest arboretum in southern Siberia are dying off as a result of pathogenic effects of Heterobasidion parviporum and H. abietinum
Yu. A. Litovka1,2, A. A. Timofeev1,2, P. V. Makolova1,2, I. N. Pavlov1,2
1Reshetnev Siberian State University of Science and Technology, Krasnoyarsk, Russian Federation
2Krasnoyarsk Science Centre of the Siberian Branch of Russian Academy of Science, V. N. Sukachev Institute of Forest, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk, Russian Federation
Keywords: root rot disease, resistance, phytopathogen, Heterobasidion abietinum, Heterobasidion parviporum
Abstract
For the first time, the phytopathogenic fungus Heterobasidion abietinum Niemelä & Коrhonena has been detected on coniferous trees Siberian pine ( Pinus sibirica Du Tour), Siberian fir ( Abies sibirica Ledeb.), and Siberian larch ( Larix sibirica Ledeb.) in southern Siberia, far from its previously established range. It is possible that its spread to the arboretum occurred due to the movement of planting material from European botanical gardens. Among other Heterobasidion species, H. parviporum Niemelä & Коrhonena is common in the dark coniferous forests of Siberia on Siberian spruce ( Picea obovata Ledeb.), Siberian pine and Siberian fir. In terms of phytopathogenicity and ability to colonize wood with well-developed resin ducts (especially Siberian spruce), H. abietinum is significantly inferior to H. parviporum . It has been established that the Siberian strains of H. abietinum and H. parviporum are closely related. A stable difference (with the formation of separate clades) only in the glyceraldehyde 3-phosphate dehydrogenase (GPD) gene. The vast areas of Siberian fir forests (about 13 million hectares), as well as regular outbreaks of mass insect infestations: (Siberian moth ( Dendrolimus sibiricus Tschetverikov), four-eyed fir bark beetle ( Polygraphus proximus Blandford), which lead to mass weakening and drying of Siberian fir, provide optimal conditions for the development of the low-pathogenic species H. abietinum . Forests that are not subjected to various types of stress are resistant to H. abietinum . Areas of forest dieback as a result of the phytopathogenic effect of H. abietinum has been established only in the conditions of an arboretum on soils after long-term agricultural use. Global climate change, accompanied by an increase in extreme weather events (droughts, storm winds, etc.), as well as an increase in anthropogenic impact (various types of logging and industrial pollution), creates conditions for a further increase in the aggressiveness of root pathogens, particularly H. abietinum .
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