Reaction to Hydrogen-Peroxide Action in Nicotiana tabacum Plants Transformed by the Cholinoxidase Gene (codA)

Abstract

Genetic engineering of glycine betaine (GB) synthesis offers a new approach to improvements in the productivity and stress resistance of cultivated plants. The possible effect of the bacterial heterologous sequence on the reaction of plants under oxidative stress (OS) induced by 3 mM of hydrogen peroxide (H2O2) was determined. The independent transgenic tobacco lines (Nicotiana tabacum L.) Cod 16 and Cod 45 with the choline oxidase (codA) gene from Arthrobacter gloiformis, which is responsible for GB synthesis, were used. The transgenic lines differed from wild-type plants with lower resistance to H2O2, which led to a more significant decrease in the pool of photosynthetic pigments and a greater intensity of lipid peroxidation and dynamics of superoxide dismutase (SOD) and peroxidase (PO) activity. In terms of OS manifestation, transgenic lines with initially similar values of GB accumulation (0.825–0.910 mmol/g) had significant differences among themselves. In the Cod 16 line, the reaction to OS induction was earlier (1 h after H2O2 treatment), and there was a more significant increase in PO activity and proline content than in the Cod 45 line and the original variety. In the Cod 45 line, there is a significant increase in SOD activity and proline content in response to OS induction 24 h after treatment, and, in contrast to the wild-type plants and the Cod 16 line, it is accompanied by a significantly higher content of carotenoids in the leaves. When genetic-engineering methods are used to increase the productivity and resistance of plants to stress, it is necessary to take into account the functional interaction of antioxidants and osmoprotectors.