The expansin gene NtEXPA5 increases stress tolerance of tobacco hairy roots through an effect on the antioxidant system

Abstract

Background: Expansins are non-enzymatic proteins involved in the softening of cell walls, the mechanism of action of which is associated with the weakening and breaking of hydrogen bonds between xyloglucans and cellulose microfibrils and is aimed at ensuring cell expansion. The aim of our work was to obtain hairy roots of tobacco with constitutive expression of the NtEXPA5 expansin gene, their morphometric analysis and assessment of the state of their antioxidant system in response to stress factors. Materials and methods: The hairy roots were obtained from transgenic tobacco plants expressing the NtEXPA5 gene under the control of the 35S promoter. Results: Constitutive expression of the NtEXPA5 gene promoted an increase in the length and dry weight of hairy roots both under normal conditions and under the action of salinity, copper sulfate, cadmium acetate, and mannitol. Both under normal conditions and under the action of stress factors in transgenic hairy roots, an increase in the activity of superoxide dismutase and the total antioxidate activity was recorded. Conclusion: Expansins exert their positive effect on the productivity and stress tolerance of plants not only through their influence on cell expansion, but also through the effect on the antioxidant system.