Scientific Journal of KubSAU

The review examines research unusual properties of RNA. RNA has the ability to act as both genes and enzymes (ribozymes). This property could offer a way around the «chicken-and-egg» problem: genes require enzymes; enzymes require genes. Furthermore, RNA can be transcribed into DNA, in reverse of the normal process of transcription. These facts are reasons to consider that the RNA world could be the original pathway to cells. The general notion of an «RNA World» is that, in the early development of life on the Earth, genetic continuity was assured by the replication of RNA and genetically encoded proteins were not involved as catalysts. There is now strong evidence indicating that an RNA World did indeed exist before DNAand protein-based life. RNA has multiple functions. Among these, "messenger RNA" carries genetic information from DNA to protein formation. RNA is often a single-stranded spiral, but also exists in double-stranded form. In 1998, Craig Mello and Andrew Fire discovered through their studies of the roundworm C. elegans a phenomenon dubbed "RNA interference". In this phenomenon, double-stranded RNA blocks messenger RNA so that certain genetic information is not converted during protein formation. This "silences" these genes, i.e. renders them inactive. The phenomenon plays an important regulatory role within a genome. Recent years have been perhaps the most fruitful period yet in terms of research in the area of mRNA stability (Phenomena: Gene Silencing; RNA interference; Identity of mRNA decay in vivo and in vitro). The elaboration of new methods in biothechnology have been presented

The differential stability of mRNA is an important mechanism for posttranscriptional regulation of gene expression in eukaryotes. Messenger RNA stability is controlled by specific genes and growth conditions. The review examines the theoretical possibility of mRNA stabilization in vivo as a consequence of replacing carbon atoms (C) or phosphorus (P), composed of nucleic acid on the silicon (Si) atom. During isolation of poly-(A)+mRNA from plant tissues by the two-cycle affinity chromatography on poly-(U)-Sepharose, regular changes in poly- (A)++mRNA yield were observed. The changes varied both with the plant genotype and growth conditions. Celite treatment of heated and unheated total RNA preparations from developing corn kernels and from green and etiolated wheat seedlings. Messenger RNA that differed in the length of poly- (A)-sequences was used for hybridization. It is evident that a reduction of poly-(A)-length causes alterations in spatial structure of mRNA, and associated proteins and cations Mg++ become accessible to celite absorption. Heating promotes melting of secondary structure, already initiated, and increases the efficiency of mRNA stabilization by celite. Interpreting the facts interact celite with mRNA in vitro and stabilization of mRNA in vivo by cycloheximide with a modern point of view can be considered with the position research of the phenomenon of RNA interference

This overview and theoretical article deals with the consideration of hypothetical possibilities for the development of molecular-kinetic markers of agricultural plants allowing to quantify the effect of genotype-environment interaction on the basis of stability studies of mRNA. The development in view is based on the results of studies of the mRNA decay identity in vivo and in vitro (the ommp system), as well as the phenomenon of RNA interference (RNAi), widely studied in plants. The ommp system has allowed to establish the relationship of the cultivar-specific growth reaction to the effects of low positive temperatures, dehydration, salinity, illumination and biologically active substances with the stability of the total and a number of gene-specific mRNAs of green and etiolated seedlings of winter soft wheat (Triticum aestivum L.) and winter barley (Hordeum vulgare L.). Similar studies of mRNA stability have been conducted on ripening grains of maize (Zea mays L.), with a particular result of the in vivo and in vitro decay identity confirmed for major mRNAs of stored proteins, 19 and 22 kDa zeins, of normal maize and mutant according to the regulatory gene opaque-2, changing the amount and stability of zein mRNA in the maturing grain of high-lysine maize. Regulatory response of the organism through RNAi is also multiple and includes neutralization of viral and bacterial infections, reaction to pathogens and biologically active substances, circadian rhythms, water stress, hypoxia, mechanical stress, mineral nutrition, salt stress and temperature changes. Unfavorable environmental influences result in an increase or decrease in the expression of certain microRNAs (miRNAs). The change in mRNA stability is an important component of the gene expression regulation system in eukaryotic cells. The main determinants of mRNA stability are in the 3'-untranslated region. It is the It is the (U)nА sequence and the degree of polyadenylation of mRNA, i.e. length of its terminal homonucleotide chain. It is to this region that mRNA molecules are complementary to miRNA. The most important component, which largely determines the regularity of the genotype-environment interaction, is the polyadenyl sequence at the 3 'end of the mRNA. Its length depends both on the genotype and on the environmental conditions. There is evidence that polyadenylation degree of mRNA determines the secondary structure of the molecule. As is known, deadenylation of mRNA reduces its lifetime, and when the poly-A-tail reaches several dozens of nucleotides, an explosive disintegration of the mRNA molecule occurs. Consequently, in a living cell the following mRNA decomposition scheme appears to be logical: shortening the poly-A-tail of the mRNA opens the sites of miRNA interaction with the 3'-non-coding region of the mRNA molecule, which causes its degradation. Thus, it is safe to assume that the interaction of mRNA and miRNA in the ommp system is the underlying process for molecular-kinetic markers under development

In the review article we present a comparative analysis of frost resistance of varieties of winter barley and sunflower (Helianthus annuus L.) by the results of freezing in the refrigerating chambers and by the hygroscopicity of mature grain. On the example of a number of varieties of both cultures, it is shown that the higher the frost resistance of the variety, the smaller the volume of the supernatant can be obtained by extracting the press cake with a solution containing magnesium cations. It is assumed that increased hygroscopicity of winter barley and sunflower press cake is associated with a relatively high content of so - called "water-soluble starch" - β-glucan polysaccharides in its grain. The possibility of regulation of the degree of hygroscopicity under the influence of potassium (KNO3), zinc (ZnSO4) and gibberellic acid (GA3) was studied on a number of sunflower varieties. It was shown that treatment with a solution of potassium (a concentration of 50 ppm KNO3) of sunflower plants at the stage of 4 leaves leads to a significant increase in hygroscopicity of grain and hardiness of plants, little effect was given treatment with zinc (30 ppm ZnSO4) and a lesser effect was observed when treating plants gibberellovaja acid (20 ppm). Potassium treatment significantly intensified the biosynthesis of free Proline, phenolic compounds and soluble proteins. When processing zinc significantly increased the content of carbohydrates in sunflower plants. Hygroscopicity showed a significant correlation with the content of free Proline (R2=0.621), phenolic compounds (R2=0.907), total carbohydrates (R2=0.673) and soluble proteins (R2=0.708). It is assumed that the treatment of plants with potassium and zinc plays a key role in increasing the hygroscopicity of grain. The results of comparative studies of frost resistance on the degree of survival of plants during freezing in cold rooms and the degree of hygroscopicity of mature grain showed that these two methods of assessing frost resistance give very close data. At the same time, in terms of simplicity and low economic costs, the proposed method of assessing frost resistance is many times superior to the method of direct freezing of plants

100 years ago, on June 4, 1920, 32-year-old Professor of the Saratov University Nikolai Ivanovich Vavilov (1887-1943) first reported at the III all-Russian selection Congress at the University of Saratov on his discovery of homological series in the study of parallelisms in the phenomena of hereditary variability by analogy with homological series of organic compounds. This discovery in genetics received the rank of law, the only one after the laws of G. Mendel. This major study was a further development of the genetic idea of C. Darwin on the origin of species. It showed the ways in which close species and genera of plants have a parallel formative process, because the crucial in the process of evolutionary development of living organisms – first of all, their genetic features. In cases where the development of a trait requires the joint and consistent action of many genes, the occurrence of homological series is inevitable, and this does not contradict the random variability of C. Darwin. In addition to its great genetic significance as a law of evolution, the law of homological series in hereditary variability is of great importance for botanists, plant breeders and breeders: it not only determines the place of each form in the plant world, but can also indicate to the breeder possible directions in his practical work. According to a number of geneticists and breeders, if G. Mendel discovered the rules of heredity, then N. I. Vavilov discovered the rules of variability