[Tobacco transformants expressing the Medicago truncatula ornithine aminotransferase cDNA].

The Medicago truncatula ornithine aminotransferase cDNA was cloned under the potent constitutive 35S RNA promoter of the cauliflower mosaic virus and transferred into the genome of tobacco Nicotiana tabacum SR1 plants. Transformed tobacco plants grew better in salinity stress, but did not differ in proline content under normal or stress conditions from control plants. It was assumed that the role of ornithine aminotransferase in the molecular mechanisms of stress resistance is not associated with additional proline synthesis.

[Silencing of the nk1 gene in the SR1 Nicotiana tabacum plants by RNA interference].

Primary transformants of SR1 Nicotiana tabacum plants with RNA interference-based silencing of the gene for extracellular ribonuclease Nk1 were constructed. It was demonstrated that the profiles of ribonuclease activities of leaf protein extracts from these plants lacked ribonuclease with electrophoretic mobility corresponding to that of the Nk1 protein. Primary transformants did not differ phenotypically from control plants. They represent a new model for investigation of the biological role of extracellular ribonucleases, including the molecular mechanisms of resistance to pathogens.

[Transgenic plants tolerant to abiotic stresses].

References are analyzed concerning production and studying of transgenic plants tolerant to various kinds of abiotic stresses; mechanisms of plant protection against stresses; the genes encoding the great spectrum of compounds giving to plants ability to survive in conditions of the stresses considerably repressing development and even lethal for control plants.

[Analysis of serial sequences of seeds in sugar beet plants upon apozygotic reproduction].

Dichotomic serial sequences of fruits of two types (with and without seeds) on shoots were analyzed in sugar beet upon apozygotic reproduction. Serial sequences were analyzed using serial statistical tests. The distribution of fruits of the two types was nonrandom in most cases. The variation of serial sequences is considered in terms of the epigenetic variation of discrete characters in plants.

[Effective expression of the gene encoding an extracellular ribonuclease of Zinnia elegans in the SR1 Nicotiana tabacum plants].

Complementary DNA for the extracellular RNase of Zinnia elegans was cloned under control of the cauliflower mosaic virus 35S RNA constitutive promoter and transferred into the Nicotiana tabacum SR1 plants. Primary tobacco transformants were characterized by a high level of RNase activity.

[Evaluation of salt tolerance in Nicotiana tabacum plants bearing an antisense suppressor of the proline dehydrogenase gene].

We studied the stress resistance of genetically modified (GM) tobacco plants bearing an antisense suppressor of the gene for proline dehydrogenase. Such plants are characterized by elevated proline content. The progeny of the transgenic plants were shown to have elevated salt tolerance.

[Increase in the level of proline and osmotic pressure of cytoplasm in transformed tobacco bearing an antisense suppressor of the proline dehydrogenase gene]. / Povyshenie soderzhaniia prolina i osmoticheskogo davleniia kletochnogo soka u transformantov tabaka, nesushchikh antismyslovoi supressor gena prolindegidrogenazy.

The antisense suppressor was constructed for proline dehydrogenase gene (PDH; a fragment of PDH from Arabidopsis in antisense orientation and under the control of 35S promoter of cauliflower mosaic virus, CMV). In Nicotiana tabacum SR1 tobacco transformants bearing antisense suppressor for PDH, the proline content and the cytoplasm osmotic pressure were increased. The proline content in these transformants varied, whereas cytoplasm osmotic pressure was stable, which seems to reflect complicated relationships between these characteristics of the plant cell.

[Production of regenerants in sugar beet]. / Poluchenie regenerantov u sakharnoi svekly.

The experimental results are presented on production of plants-regenerants of the sugar beet (Beta vulgaris L.) via callus formation or direct organogenesis from the leaf tissues. The method of aseptic treatment was developed for the seeds with strong bacterial and fungal invasion. The regenerant plants were obtained in the presence of various concentrations of synthetic hormones, such as cytokinin (6-benzaminopurine) and auxin (naphthylacetic acid), and inhibitor of auxin transport in plants (2,3,5-triiodobenzoic acid). This combination of growth regulators made it possible to avoid callus formation. The genotype of initial plants affected the capacity for callus formation and regeneration. The temperature influenced rhizogenesis in regenerants.