Water deficiency tolerance of genetically modified common wheat cv. Zymoyarka, containing a heterologous ornithine-δ-aminotransferase gene
Keywords: wheat, transgenic plants, proline metabolism gene, soil drought, photosynthetic pigments, grain productivity
AbstractAim. To determine water deficiency tolerance of genetically modified common wheat plants (Triticum aestivum L., cv Zymoyarka), containing the heterologous ornithine-δ-aminotransferase gene, based on the analysis of grain productivity and physiological and biochemical characteristics in transgenic and non-transgenic genotypes. Methods. Biochemical spectrophotometric assays: the enzyme ornithine-δ-aminotransferase activity, the free L-proline content, and the photosynthetic pigments content; biotechnological: Agrobacterium-mediated transformation in planta; physiological: morphometric traits and elements of grain productivity; mathematical statistics. Results. It was established that the presence of an additional copy of the ornithine-δ-aminotransferase gene in transgenic plants leads to higher activity of the ornithine-δ- aminotransferase enzyme: by 1.6 times higher on average for all lines as compared to the non-transgenic plants at 70 % of fi eld capacity and by 1.5 – at 30 % fi eld capacity. However, transgenic plants did not differ significantly from the original variety in the free L-proline content either under optimal water conditions or under soil drought. The increase in the total chlorophyll (a + b) content in flag leaves of transgenic plants was established under conditions of both optimal water supply and drought, as compared with the original genotype (increase by 5–7 % and 8–11 %, respectively). The enhanced expression of the orni- thine-δ-aminotransferase gene in the transgenic plants stimulated root growth both under optimal and stressful conditions: the root length of the transformed plants exceeded that of the original variety by 3.4–3.9 cm in the variant with optimal water supply, and by 4.2–4.6 cm – under drought. They were also characterized by a more developed root system. Dry root weight of the transgenic plants exceeded the original variety both in the control (by 23–27 %), and under drought (by 37– 44 %). Under drought, the root dry weight decreased by 29 % in the plants of the original variety, compared 70 % fi eld capacity, and by 11–15 % in the lines. Under 30 % field capacity, the transgenic lines also exceeded non-transformed plants in the number of grains from the whole plant (on average for 3 lines by 26 %) and in the grain weight (by 22 %). Transgenic plants are characterized by the formation of a higher productive shoots number: from 3.2 to 3.4 compared with 2.5 in non-transgenic plants at 70 % fi eld capacity and 2.7–3.1 vs 2.2 at 30 % field capacity it was found. Conclusions. Thus, the analysis of genetically modified common wheat plants cv. Zymoyarka, containing the heterologous alfalfa ornithine-δ- aminotransferase gene, by yield structure elements, morphometric parameters and photosynthetic pigment content showed their better tolerance to soil drought as compared to non-transgenic plants. We explain the improvement of grain productivity of the whole plant in transgenic wheat lines with an additional copy of ornithine-δ-aminotransferase gene by the fact that they have a better developed root system (dry root weight of the transgenic plants exceeded the original variety both in the control by 23–27 %, and under drought by 37–44 %) and a higher (on average for 3 lines – 3.3 compared to 2.5 in non- transgenic plants at 70 % fi eld capacity and 2.9 vs 2.2 at 30 % fi eld capacity) number of productive shoots than in the origi- nal variety both under optimal and insuffi cient water supply.
How to Cite
Dubrovna, O., Priadkina, G., Mykhalska, S., & Komisarenko, A. (2021). Water deficiency tolerance of genetically modified common wheat cv. Zymoyarka, containing a heterologous ornithine-δ-aminotransferase gene. Agricultural Science and Practice, 8(1), 14-28. https://doi.org/10.15407/agrisp8.01.014
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