Physiological and biochemical characteristics of transgenic winter wheat plants withoverexpression of ornithine-d-aminotransferases gene

Abstract

Ornithine-d-aminotransferase may be an important regulator of cellular metabolism, as the reaction catalyzed by this enzyme links a number of biochemical systems. Introducing the exogenous ornithine-d-aminotransferase gene (oat)into the plant genome is one of the promising methods of creating wheat genotypes resistant to abiotic stresses. The aim of this study has been to determine the physiological and biochemical characteristics of transgenic plants of new promising genotypes of winter soft wheat of the seed generation T2 with overexpression of the ornithine-d-aminotransferase gene under normal and stressful conditions. The enzyme activity, the free proline content, the photosynthetic pigments content and morphometric indicators were studied. It was shown that the presence of an additional copy of the oat gene in transgenic plants leads to an increase in the activity of the ornithine-d-aminotransferase enzyme (by 1.5—1.7 times, compared to the original plants), but they do not significantly differ from the original genotypes in terms of the free of L-proline content neither under physiological conditions nor under conditions of water deficit. It was found that under stressful conditions during period booting — anthesis, genetically modified plants of the seed generation T2 kept a higher total chlorophyll content (on average by 10 %) compared to the original genotypes, while under physiological conditions the difference between them was insignificant. Under drought conditions, an increase in the carotenoids to chlorophylls ratio in the original genotypes, compared to transgenic plants, was also established. A comparative analysis of the morphometric indicators of the main shoot at full maturity showed that under physiological conditions, the plants of transgenic lines did not differ from the plants of the original genotypes in spike length, however, they prevailed in terms of the main shoot stem height and the length of the roots.