Differences in Cytoskeleton Reorganization in Tobacco Root Cells in the Original Samsun Variety and a Transgenic Line with FeSOD1 Overexpression under Salinity

Abstract

The aim of the study was to study the state and reaction of cytoskeletal elements, microtubules and actin filaments, in root cells of Samsun tobacco plants and its transgenic line expressing the FeSOD1 gene from Arabidopsis thaliana with the pea rbcS leader sequence for the localization of the gene product in chloroplasts encoding Fe-dependent superoxide dismutase, constitutively inducing intracellular oxidative stress, by increasing the H₂O₂ pool for a long-term effect of moderate concentrations of NaCl and Na₂SO₄. The main hypothesis was to identify the positive protective effect of controlled constant oxidative stress on the stability of the most sensitive system that provides growth by division and growth by extension (the tubulin cytoskeleton) and effective intracellular transport and structural stability (the actin filament system). Localization of the microtubule cytoskeleton and actin filaments using antibodies to tubulin clone DM1α and actin clone 10-B3 by transmission electron microscopy and immunocytologically, detected by treatment with the second antibodies conjugated with Alexa‑488, made it possible to establish signs of reorganization and disassembly of the actin filament network under the action of NaCl and Na₂SO₄ as in control and in transgenic plants. At the same time, in transgenic plants, differences can be noted even without exposure, which indicates the effectiveness of this method for stimulating a protective response. These data suggest that the state of the system of the tubulin cytoskeleton and actin filaments may be an indicator of the resistance of FeSOD1 transgenic plants to salinity. A relationship has also been established between the reorganization of the cytoskeleton and vacuolization, especially with Na₂SO₄.