Microevolutionary differentiation of cereal tetraploid species by formation of recombinant genomes

The process of microevolutionary differentiation of cereals by formation of recombinant genomes was studied in dynamics (F6–F17) with tetraploid wheat-rye amphidiploids as examples. Evidence that joint growing of tetra ploid amphidiploids having a common (pivotal) genome in their composition and differing in secondary (differential) genomes leads to their hybridization with high probability has been found. The forms developed are characterized by a very wide range of variability caused by different combinations of chromosomes and chromosome segments in dif­ferential genomes yet maintain the same structure of the pivotal genome. Intergenomic recombinations at the level of intact chromosomes were characteristic of homeologous groups with a high rate of stabili zation of the chromosomal composition, and recombinations at the level of chromosomal segments, of groups with a low stabilization rate, where heterologous chromosome pairs remained preserved for a long time. Dominance of regulatory genetic systems of the pivotal genome provides a high pairing level of homeologues from heterologous pairs in meiosis followed by intergenomic recombinations at the level of chromosome segments. Experimen tal data suggest that newly developed tetraploid forms interbreed easily forming a single hybrid zone, where permanent redistribution of genetic material of differential genomes and further range expansion of genotypic variability available to selection take place during alternation of generations whereby such a zone becomes a poten tial centre of speciation. Subsequent adaptive radiation of hybrid material in an ecologically separated environment occurs by selection of forms with different variants of the recombinant genome in various ecological niches

The creation and characterization of the bread wheat line with a centric translocation T2DL.2RL

The development of bread wheat introgressions with alien genetic material from cultural and wild Triticeae species is an effective method for expanding the wheat gene pool necessary for breeding. To date, numerous collections of introgressions as substitutions and chromosome modifications have been obtained; however, the creation and study of wheat with new valuable traits still remain an important line of research. Rye Secale cereale L., whose chromosomes carry genes that control valuable economic and biological characteristics and properties, is widely used to produce new wheat forms. In this study, a wheat-rye translocation obtained by backcrossing the wheat-rye disomic-substitution line 2R(2D)1 with the variety Novosibirskaya 67 was characterized. The chromosomal composition of karyotypes was studied using fluorescent in situ hybridization and C-banding. Two centric translocations, derived from two long arms of chromosomes 2D and 2R, T2DL.2RL, were identified, the remaining 40 wheat chromosomes did not undergo modifications. Meiosis in the lines was stable. Chromosomes T2DL.2RL formed bivalents in all meiocytes, which confirmed their homology. The morphological characteristics of the spike in the T2DL.2RL line and Novosibirskaya 67 did not differ. A comparative analysis of productivity between the T2DL.2RL translocation line and the parental forms, Novosibirskaya 67 and the 2R(2D)1 line, was carried out. The T2DL.2RL line is inferior to Novosibirskaya 67 in all characters with different confidence levels. The productivity characters of the 2R(2D)1 line exceeded or did not differ from those of T2DL.2RL, however, the mass of 1000 grains was significantly lower. The results showed the effect of the T2DL.2RL translocation on the trait “plant height”. This character was significantly lower than that of Novosibirskaya 67 in two vegetation periods. Consequently, the T2DL.2RL translocation reduces plant height and productivity

Молекулярно-генетическая характеристика образцов озимой мягкой пшеницы в связи с селекцией на устойчивость к полеганию

The objective of the study was to analyze the genomic structure and allelic composition of the dwarfing Rht-B1, Rht-D1 and Rht8 genes in 37 varieties and breeding samples of soft winter wheat in connection with breeding for lodging resistance in the Republic of Belarus. The molecular cytogenetic marking (C-banding) and DNA typing of genotypes were used. As a result, the analysis of the chromosomal composition of the breeding material showed that 21 winter wheat samples are characterized by the standard karyotype with the genomic structure AABBDD (2n = 42). Five variants of translocations affecting the chromosomes 1B, 3B, 5B, 6B, and 7B were revealed in the karyotypes of the remaining samples. It was found that the chromosomes of the 2nd and 4th homologous groups, in which the main dwarfing genes (Rht-B1, Rht-D1, and Rht8) are localized, did not undergo structural changes. Genotyping showed that 45.9 % of the samples contain one of the dwarfing alleles (Rht-B1b, Rht-D1b, Rht8c) in their genotype. A combination of two commercially significant alleles (Rht-B1b and Rht8c) in the genotype were identified in one of the winter wheat samples. The genotype with a combination of the Rht-B1a, Rht-D1a and Rht8b alleles occurred with the highest frequency (37.8 %) in the analysed breeding material. The Rht-B1b, Rht-D1a, Rht8b; Rht-B1a, Rht-D1a, Rht8a genotypes showed the frequency of 16.2 %. The Rht-B1a, Rht-D1a, Rht8c; Rht-B1a, Rht-D1b, Rht8b; Rht-B1a, Rht-D1b, Rht8j genotypes were identified in 5.4 % of the samples; the Rht-B1a, Rht-D1b, Rht8а genotypes – in 8.1 % of the samples. The analysis of the plant height, taking into account the karyotyping and genotyping data showed that the targeted selection of the most efficient allelic combinations of dwarfing genes is important for the cultivation region. The studies carried out allow us to suggest that the selection by the overwintering level can contribute to the fixation of the Rht8b allele in the breeding material, which is apparently associated with better winter hardiness in the conditions of Belarus.Цель – анализ геномной структуры и аллельного состава генов короткостебельности Rht-B1, Rht-D1 и Rht8 у 37 сортов и селекционных образцов озимой мягкой пшеницы в связи с селекцией на устойчивость к полеганию в Республике Беларусь. Методы. Молекулярно-цитогенетическое маркирование (С-бэндинг) и ДНК-типирование генотипов. Результаты. В ходе анализа хромосомного состава селекционного материала установлено, что 21 образец озимой пшеницы характеризуется стандартным кариотипом с геномной структурой AABBDD (2n = 42). В кариотипах остальных образцов выявлено пять вариантов транслокаций, затрагивающих хромосомы 1В, 3В, 5В, 6В и 7В. Установлено, что хромосомы 2-й и 4-й гомеологичных групп, в которых локализованы основные гены короткостебельности Rht-B1, Rht-D1 и Rht8, не подверглись структурным изменениям. В результате генотипирования показано, что 45,9 % образцов содержат в генотипе один из аллелей короткостебельности (Rht-B1b, Rht-D1b, Rht8с). Сочетание в генотипе двух коммерчески значимых аллелей короткостебельности Rht-B1b и Rht8с выявлено у одного образца озимой пшеницы. С наибольшей частотой (37,8 %) в проанализированном селекционном материале встречался генотип с комбинацией аллелей Rht-B1а, Rht-D1а и Rht8b. С частотой 16,2 % присутствовали генотипы Rht-B1b, Rht-D1а, Rht8b; Rht-B1а, Rht-D1а, Rht8а. Генотипы Rht-B1а, Rht-D1а, Rht8с; Rht-B1а, Rht-D1b, Rht8b; Rht-B1а, Rht-D1b, Rht8j выявлены у 5,4 % образцов, генотип Rht-B1а, Rht-D1b, Rht8а – у 8,1 % образцов. Заключение. Анализ высоты растения с учетом данных кариотипирования и генотипирования показал важность целенаправленного подбора наиболее эффективных для региона возделывания сочетаний аллелей генов короткостебельности. Проведенные исследования позволили предположить, что отбор по уровню перезимовки может способствовать закреплению в селекционном материале аллеля Rht8b, ассоциированного, по-видимому, с лучшей зимостойкостью в условиях Беларуси

Measles in children. Weren’t you waiting? What should a pediatrician know

From a long time ago to the present day, measles remains one of the leading health problems in the world. The main reason for this is high mortality from measles – 1/500. Despite the availability of an effective and safe vaccine, which was discovered in 1963, there are still epidemic outbreaks of measles. According to WHO, there were 413,308 confirmed cases in 187 countries and 764 deaths during 2019. Most measles deaths are due to complications associated with the disease.Complications are most common in children under five or in adults over 30 years of age. The most serious complications include blindness, encephalitis leading to cerebral edema, severe diarrhoea and associated dehydration, purulent otitis and severe lower respiratory tract infections such as pneumonia. In a study from 2019, Michael J. Mina and colleagues showed that after measles in the group of unprivileged people, 11 to 73% of previous immune memory is “erased”. Currently, there is no specific etiotropic therapy for measles. One of the pathogenetic links in therapy is the use of interferon replacement therapy. According to the Federal Clinical Recommendations and WHO recommendations, the use of recombinant interferon α-2B and vitamin A is recommended. The effectiveness of interferonotherapy for measles was first shown in 1992 by the Leopardi R team. This study showed that the secretion of measles virus in human peripheral blood mononuclear cells was gradually reduced by increasing the concentrations and blocked at the concentration of interferon α-2B in 1000 units/ml. Moreover, at the XXIV World Congress of Neuroscientists (WCN) it was noted that the safest and most effective method of treatment of subacute sclerosing panencephalitis, one of the severe complications of measles, is recombinant human α-2B interferon

RYE CHROMATIN INTROGRESSION IN THE BREAD WHEAT GENOME: CYTOGENETIC ASPECTS

Alien chromatin introgression into the genome of common wheat Triticum aestivum L. is the most efficient way to enrich the gene pool of this crop. To improve the breeding value of wheat accessions, rye Secale cereale L is used as a donor of characters. Transfer of rye genetic material has certain specific features. The combination of the two cereal genomes in a single nucleus results in imbalance in all genetic systems. Fertility restoration in amphihaploids is the first step in the formation of introgression accessions. It is followed by the hybrid genome reorganization, which leads to cytological and genetic stability in the diploid progeny. In this paper, we present and analyze results that were obtained in the study of the two steps of wheat-rye hybrid genome reorganization: (1) breaching of F1 hybrid sterility (cytogenetic mechanisms of unreduced gamete formation) and (2) reorganization of wheat subgenomes during the introgression of single rye chromosomes

Karyotype Reorganization in Wheat–Rye Hybrids Obtained via Unreduced Gametes: Is There a Limit to the Chromosome Number in Triticale?

To date, few data have been accumulated on the contribution of meiotic restitution to the formation of Triticum aestivum hybrid karyotypes. In this study, based on FISH and C-banding, karyotype reorganization was observed in three groups of F5 wheat–rye hybrids 1R(1A) × R. Aberrations, including aneuploidy, telocentrics, and Robertsonian translocations, were detected in all groups. Some of the Group 1 plants and all of the Group 2 plants only had a 4R4R pair (in addition to 1R1R), which was either added or substituted for its homeolog in ABD subgenomes. In about 82% of meiocytes, 4R4R formed bivalents, which indicates its competitiveness. The rest of the Group 1 plants had 2R and 7R chromosomes in addition to 1R1R. Group 3 retained all their rye chromosomes, with a small aneuploidy on the wheat chromosomes. A feature of the meiosis in the Group 3 plants was asynchronous cell division and omission of the second division. Diploid gametes did not form because of the significant disturbances during gametogenesis. As a result, the frequency of occurrence of the formed dyads was negatively correlated (r = −0.73) with the seed sets. Thus, meiotic restitution in the 8n triticale does not contribute to fertility or increased ploidy in subsequent generations

Frequently ill children: has everything been resolved?

The article presents an analysis of causes of recurrent respiratory infections in children. The special attention is drawn to the need for improvement of the epidemiological, anamnestic, social and other data to clarify the causes and provoking factors for increased respiratory morbidity. It has been shown that allergic diseases, immunodeficiency states, persistent herpetic infections, functional gastrointestinal disorders, etc. are often hidden.under the mask of “frequently ill children”. This determines the importance of a detailed assessment of clinical manifestations of each episode of the disease and the correct interpretation of examination results for the timely diagnosis specification. It was proposed to move from targeting the “frequently ill children” group to nosological verification, which have a high level of respiratory morbidity. It has been proved that early arriving at a diagnosis makes it possible to timely prescribe etiopathogenetic therapy, which significantly increases the effectiveness of treatment. The article presents an analysis of clinical studies of the effectiveness and safety of OM-85 immunomodulator of bacterial origin in children with recurrent respiratory diseases