ИСТИНА

Statement of the Problem: Mitochondria are the most important organelles of eukaryotic cells, performing various functions in the cell, the main one of which is respiration. Mitochondria (including fungal mitochondria) undergo permanent fragmentation to small organelles and reverse assembly into larger filamentous structures. In the fungi described the extreme form of mitochondrial assembly - the mitochondrial reticulum - a continuous network of filamentous mitochondria distributed throughout the cell. We found that some species of xylotrophic basidiomycetes form extra-long mitochondria. The purpose of this study is to study of extra-long mitochondria of xylotrophs. Results of the study will be at the same time a contribution to understanding how fungi have adapted to the using of such "difficult" substrate as wood and a contribution to the expansion of our knowledge about such important eukaryotic organelle as mitochondrion. Methodology & Theoretical Orientation: To study the dynamics of the distribution of mitochondria used methods of fluorescence microscopy, and to study the ultrastructure - transmission electron microscopy. We applied an inhibitory analysis to test the hypothesis about the formation of giant mitochondria in xylotrophs as an adaptation to the conditions of fasting for nitrogen and protection against autophagy. Conclusion & Significance: Extra-long mitochondria are continuous long channels located along the longitudinal axis of mycelial cells clearly differ from the mitochondrial reticulum. Xylotrophic fungi can destroy wood, which is extremely poor in nitrogen content. It can be assumed that the formation of extra-long mitochondria in the mycelium of xylotrophs cultivated on such media is one of the adaptations of wood-destroying fungi to life under nitrogen limited. The work was supported by the Russian Foundation for Basic Research (RFBR № 18-04-00266).