Formation of Atypical Tubulin Structures in Plant Cells as a Nonspecific Response to Abiotic Stress

E. N. BARANOVA1, N. K. CHRISTOV4, L. V. KURENINA1, M. R. KHALILUEV1,2, E. G. TODOROVSKA4 and Е. А. SMIRNOVA1,3
1 All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550,
2 Russian Timiryazev State Agrarian University Moscow, 127550 Russia
3 Lomonosov MSU Moscow, 119991 Russia
4 AgroBioInstitute, BG-1164 Sofi a, Bulgaria

Abstract

BARANOVA, E. N., N. K. CHRISTOV, L. V. KURENINA, M. R. KHALILUEV, E. G. TODOROVSKA and Е. А. SMIRNOVA, 2016. Formation of atypical tubulin structures in plant cells as a nonspecifi c response to abiotic stress. Bulg. J. Agric. Sci., 22: 987–992

In response to abiotic and biotic stress factors the production of reactive oxygen species (ROS) in plant cells is increased and series of cascade reactions for their neutralization are being triggered. Targets of ROS in cells can be various biochemical and physiological processes, as well as cellular organelles including the cytoskeleton. Many abiotic stress factors, by provoking increase of the level of ROS in plant cells, elicit reorganization of the microtubules leading to disruption of mitosis. The reorganization of interphase and mitotic microtubule system was proposed to be an integral part of the response of cells to external stimuli. The state of microtubule system (tubulin cytoskeleton) under various abiotic stresses, including salinity, low temperatures, Al toxicity and fl ooding, was analysed in cells of representatives of family Solanaceae (S. lycopersicum L., S. tuberosum L. and N. tabacum L.) and cereals (T. aestivum L. and H. vulgare L.) by using transmission electron microscopy. Various tubular structures that were structurally different from microtubules were observed in plant cells subjected to abiotic stress. Fibrillar bundles with different densities of their constituent components, macrotubules, orderly packed paracrystalline aggregates and strands having hexagonal packing in cross sections, were observed in potato leaf mesophyll cells under low positive temperature stress, wheat root cells subjected to fl ooding stress, barley root cells under Al toxicity stress, as well as in root cells of tomato and tobacco under salinity stress imposed by NaCl or Na2SO4. The structure of these cytoskeletal elements is identical to stable atypical tubulin polymers induced by different chemical treatments. The presented data suggests that the formation of abnormal tubulin structures in plant cells is a common and non-specifi c response to various abiotic stress factors.

Key words: tubulin, cytoskeleton, microtubule, stress condition, ultrastructure

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