Molecular markers in the genetic analysis of crossability of bread wheat with rye

Bread wheat (Triticum aestivum L.), the varieties of which are widely used for the grain production, is difficultly crossable with related species of Triticeae Dum. This factor limits the chance of introduction of alien genetic material into the wheat gene pool and the possibility of new varieties breeding with good adaptation to adverse environmental factors. The crossability between wheat and related species is controlled by Kr1-Kr4 genes (Crossability with Rye, Hordeum and Aegilops spp.) and the SKr gene (Suppressor of crossability). SKr and Kr1 have the largest influence on the trait. In the case of the recessive alleles, these genes do not function and the quantity of hybrid seeds after pollination with alien species can achieve more than 50 %. SKr is located on 5BS between the GBR0233 and Xgwm234 markers, closely linked with the markers Xcfb341, TGlc2 and gene12. Kr1 was mapped on 5BL, proximally to the Ph1 gene, between the EST-SSR markers Xw5145 and Xw9340. The markers of SKr were used to control the transfer of its recessive allele into other wheat genotypes, which made it possible to obtain highly crossable forms. However, the advantages of using the SKr and Kr1 markers in marker-assisted selection and in the screening of ex situ collections are not sufficiently studied. The published Kr1 sequence for varieties with different crossability offers great prospects, because it will be possible to create allele-specific markers. In this review, the following issues are considered: genetic resources created by wheat and rye hybridization, the geographical distribution of easy-to-cross forms of wheat, genetic control of the wheat and rye compatibility, advances of the use of molecular markers in the mapping of Kr-genes and their transmission control

A system of molecular markers to identify alleles of the Rht-B1 and Rht-D1 genes controlling reduced height in bread wheat

Mutant alleles of the Rht-B1 and Rht-D1 (Reduced height) genes are widely used in bread wheat breeding for the development of intensive-type cultivars. These genes and their f lanking regions have been sequenced and the point mutations leading to the nonsense codons (Rht-B1b, Rht-B1e, Rht-B1p and Rht-D1b alleles) and various insertions (Rht-B1c, Rht-B1h and Rht-B1i-1) associated with a change in plant height have been described. DNA-markers based on the allele-specif ic PCR have been developed to identify single-nucleotide changes. However, the use of such technique imposes stringent PCR conditions, and the resulting data are not always unambiguous. An alternative can be found in the CAPS technology: it detects differences in sequences by digesting PCR products. In the absence of restrictases capable of digesting DNA at the point mutation site, restriction sites can be introduced into the primer sequence (derived CAPS). The aim of this study was to propose a system of CAPS-, dCAPS- and STS-markers for identifying alleles of the reduced height genes frequently used in breeding programs. Three CAPS have been developed to identify the Rht-B1b, Rht-D1b, Rht-B1p alleles, as well as two dCAPS for Rht-B1b, Rht-B1e. STS-markers for the insertioncontaining alleles Rht-B1c, Rht-B1h and Rht-B1i-1 have been selected from publications. The proposed markers were tested during the genotyping of 11 bread wheat accessions from the VIR collection with the abovementioned mutant alleles and the wild-type Rht-B1a and Rht-D1a. The presence of nonsense mutations was also conf irmed by the results of allele-specif ic PCR. This marker system, along with the existing ones, can be used to identify dwarf ing alleles of the Rht-B1 and Rht-D1 genes in bread wheat for genetic screening of accessions from ex situ collections and/or for marker-assisted selection

WINTER HARDINESS OF BREAD WHEAT FROM THE VIR COLLECTION IN ENVIRONMENTS OF THE NORTHWESTERN AND CENTRAL BLACK SOIL REGIONS OF RUSSIA

Background. Winter wheat resistance to adverse winter­ing conditions is one of the most important adaptive charac­teristics. To obtain high yields, modern wheat cultivars should have various protective reactions. For their success­ful combination in one genotype, the availability of appro­priate initial material is of great importance. In Russia, the accessions from the VIR collection are traditionally used as initial material for wheat breeding. The aims of the present study were (1) to evaluate winter hardiness in accessions from the VIR collection in a field test, and (2) to use the ob­tained data and those on the geographical origin of acces­sions for making up the target sub-collection and perform­ing its eco-geographical studies.Materials and methods. The initial sample for field screening contained 431 acces­sions of common winter wheat from different regions of Russia and the former USSR, and 484 accessions from 18 foreign countries. Winter hardiness of these accessions was tested in the environmental conditions of the North­western region (Pushkin, 59°41′N 30°20′E, 2006/2007, 2007/2008 and 2013/2014) and of the Central Black Soil re­gion (Yekaterinino, 52°59′N 40°50′E, Tambov Province, 2007/2008 and 2008/2009). The degree of winter hardi­ness was determined in accordance with the technique de­veloped at VIR.Results and conclusions. In 2006/2007, in Pushkin, a high and a very high degree of winter hardiness was displayed by 114 accessions with the origin from Rus­sia and the former USSR as well as by 12 accessions from foreign countries. Based on the obtained data and taking into account the diversity of the geographical origin of ac­cessions, the target sub-collection was formed, whose ac­cessions were subjected to eco-geographical two-year field studies (Pushkin, 59°41′N 30°20′E, 2007/2008, 2013/2014, and Yekaterinino, 52°59′N 40°50′N, Tambov Province, 2007/2008, 2008/2009). The Friedman’s variance analysis has shown that variation on winter hardiness in 158 acces­sions from the target sub-collection was determined by the environmental conditions of wheat cultivation (χ2э = 256.7; df = 4; χ2W=0.05 = 9.5) and by genetic differences between ac­cessions (χ2э = 239.3; df = 157; χ2W=0.05 = 187.2) at that effect of the prior was stronger than that of the latter. By using the cluster analysis (k-means algorithm), the target sub-collec­tion structure has been revealed. Twelve accessions that overwintered well at both geographical locations during all the years of testing were identified

Molecular-genetic bases of plumage coloring in chicken

The color of plumage in birds is an important feature, often determining descent to a particular species or breed. It serves as a key factor in the interaction of birds with each other due to their well-developed visual perception of the surrounding world. In poultry including chickens, the color of the plumage can be treated as a genetic marker, useful for identifying breeds, populations and breeding groups with their specific traits. The origin of diverse color plumage is the result of two interrelated physical processes, chemical and optical, due to which pigment and structural colors in the color are formed. The pigment melanin, which is presented in two forms, eumelanin and pheomelanin, is widely spread in birds. The basis for the formation of melanin is the aromatic amino acid tyrosine. The process of melano-genesis involves many loci, part of the complex expression of plumage color genes. In birds, the solid black color locus encodes the melanocortin 1 receptor (MC1R), mutations in which lead to a change in receptor activation and form different variants of the E locus. Using the GWAS analysis, possible genes affecting the formation of color in chickens were detected. The biosynthesis and types of melanin are affected by the activity of the enzyme tyrosine, and mutations in the tyrosinase gene (TYR) cause albinism in different species. The formation mechanism of brown, silver, gold, lavender and a number of other shades is determined by the influence on the work of the MC1R genes and TYR specific modifier genes. Thus, locus I currently associated with the PMEL17 gene inhibits the expression of eumelanin, and the MLPH gene affects tyrosinase function. Research on the mechanisms of formation of the secondary coloring of plumage in chickens is being actively conducted nowadays. The formation of a marble feather pattern is associated with the mutation of the endothelin B2 receptor (EDNRB2), in the coding part of the gene of which a polymorphism is found associated with the mo locus. The molecular base that causes the feather banding (locus B and autosomal recessive banding) is identified. Today, only some genes that determine the color of the plumage of chickens are studied and described. Different genes can produce similar plumage patterns, and different phenotypes can be determined by the polymorphism of a single gene. Using molecular methods, you can more accurately identify these differences. This overview shows the nature of melanin coloration in birds using the example of chickens of various breeds and also attempts to systematize knowledge about the molecular-genetic mechanisms of the appearance of various types of coloration

Resistance of old winter bread wheat landraces to tan spot

Background. The most effective and environmentally safe way to combat wheat diseases is to produce cultivars resistant to their pathogens. For this purpose, old landraces are often used as genetically diverse sources of traits important for breeding. In the process of wheat breeding for resistance to tan spot caused by the fungus Pyrenophora tritici-repentis (Died.) Drechs. (abbr. Ptr), selection is carried out against the dominant allele of Tsn1, the gene of sensitivity to the toxin Ptr ToxA, which induces necrosis and represents the main pathogenicity factor of Ptr controlled by the ToxA gene. The aim of the study was to characterize a set of bread wheat (Triticum aestivum L.) accessions from the VIR collection for resistance to various Ptr populations, genotype these accessions using Xfcp623 – a DNA marker of the Tsn1 gene, and identify sources of tan spot resistance.Materials and methods. Sixty-seven accessions of winter bread wheat landraces were studied. Seedling resistance to two Ptr populations was assessed using a 5-point scale adopted at VIZR. The allelic state of Tsn1 was identified by PCR.Results. Dominant alleles of Tsn1 were found for 55% of the studied accessions. Seventeen accessions were resistant or moderately resistant to two Ptr populations and an isolate from Krasnodar Territory previously used for their characterization. Nine of them had the tsn1tsn1 genotype, and 8 had Tsn1Tsn1. The accessions mainly belonged to three agroecological groups proposed by N. I. Vavilov: “steppe winter bread wheat (Banatka wheats)”, “North European forest awnless bread wheats (Sandomirka wheats)”, and “Caucasian mountain winter bread wheat”.Conclusion. The identified 17 accessions resistant to Ptr are potential breeding sources of resistance. In the studied set of accessions, no significant relationship was found between the allelic state of the Tsn1 gene in the accession and its response to the infection with pathogen populations, including isolates with the ToxA gene

Efficiency of using SNP markers in the <i>MSTN</i> gene in the selection of the Pushkin breed chickens

In the poultry industry, indicators reflecting the growth rate of young stock and the exterior characteristics of chickens are important benchmarks for breeding. Traditional selection based on phenotypic evaluation is characterized by low efficiency with a low character inheritance ratio and is difficult to apply in small groups of animals and birds bred in bioresource collections. The use of molecular genetic markers associated with economically important traits makes it possible to carry out early selection of birds. This entails an increase in the profitability of the poultry industry. Recently, single nucleotide polymorphisms (SNPs) have served as convenient markers for selection purposes. For five generations (P1–P5), an experimental selection of hens of the Pushkin breed was carried out for live weight. It was based on selection for single nucleotide polymorphism rs313744840 in the MSTN gene. As a result, a significant increase in the frequency of allele A in this gene, from 0.11 to 0.50, took place. The association of SNP markers with meat qualities in the experimental group led to changes in the exterior profile of an adult bird at 330 days of age. The individuals with the AA and AG genotypes had the greatest live weight and longest body. As a result of selection, the bird on average became larger due to an increase in the number of heterozygous individuals with long bodies and large chest girths. The depth of the chest and the width of the pelvis increased due to an increase in the frequency of allele A in the experimental population. A tendency towards an increase in these indicators with the substitution of G with A in the genotype was found. Saturation of the population with desirable alleles led to an increase in the average live weight of the chickens. Analysis of the exterior parameters of adult birds showed that this growth is achieved by increasing the depth and volume of the bird body, and not by increasing the length of the limbs. Thus, marker selection carried out for five generations in the experimental population of Pushkin breed chickens to increase body weight has reliably (p &lt; 0.001) changed the exterior profile of adult birds

Femtosecond coherent spectroscopy of four-wave mixing and the spectroscopy of transient gratings in GaAs/AlGaAs semiconductor heterostructures at room temperature

Results from femtosecond coherent spectroscopy of four-wave mixing in GaAs/AlGaAs semiconductor heterostructures at room temperature are presented. Electron diffusivities and their spins are found via spectroscopy of transient gratings. Investigations in the field of spin transport in GaAs/AlGaAs heterostructures are performed with the aim of their possible use in spintronics applications. © 2014 Allerton Press, Inc

PN G068.1+11.0: A young pre-cataclysmic variable with an extremely hot primary

© 2016, Pleiades Publishing, Ltd.An analysis of spectroscopic and photometric data for the young pre-cataclysmic variable (PCV) PN G068.1+11.0, which passed through its common-envelope stage relatively recently, is presented. The spectroscopic and photometric data were obtained with the 6-m telescope and Zeiss-1000 telescope of the Special Astrophysical Observatory. The light curves show sinusoidal brightness variations with the orbital-period time scale and brightness-variation amplitudes of Δm = 1.m41, 1.m62, and 1.m57 in the B, V, and R bands, respectively. The system’s spectrum exhibits weak HI (Hβ–Hδ) andHeII λλ4541, 4686, 5411 Å absorption lines during the phases of minimum brightness, as well as HI, HeII, CIII, CIV, NIII, and OII emission lines whose intensity variations are synchronized with variations of the integrated brightness of the system. The emission-line formation in the spectra can be fully explained by the effects of fluorescence of the ultraviolet light from the primary at the surface of the cool star. All the characteristics of the optical light of PN G068.1+11.0 confirm that it is a young PCV containing sdO subdwarf. The radial velocities were measured from a blend of lines of moderately light elements, CIII+NIII λ4640 Å, which is formed at the surface of the secondary due to reflection effects. The ephemeris of the system has been improved through a joint analysis of the radial-velocity curves and light curves of pre-cataclysmic variable, using modelling of the reflection effects. The fundamental parameters of PN G068.1+11.0 have been determined using two evolutionary tracks for planetary-nebula nuclei of different masses (0.7 M⊙and 0.78M⊙). The model spectra for the system and a comparison with the observations demonstrate the possibility of refining the components’ effective temperatures if the quality of the spectra used is improved

The intermediate-age pre-cataclysmic variables SDSS J172406+562003 and RE J2013+4002

We have analyzed the physical status of the pre-cataclysmic variables SDSSJ172406+562003 and RE J2013+4002, which have evolved after their common-envelope stage a time t = 10 6-10 7 years. Spectroscopy and photometry of these systems were performed with the 6-m and 1-m telescopes of the Special Astrophysical Observatory. We demonstrate that emission lines in the spectra were formed solely by the reflection of radiation emitted by the white dwarfs on the surfaces of their cool companions, under conditions close to local thermodynamic equilibrium. These effects are also responsible for most of the objects' photometric variability amplitude. However, comparing the light curves of SDSS 172406 from different epochs, we find aperiodic brightness variations, probably due to spottedness of the surface of the secondary. Jointly analyzing the spectra, radial-velocity curves, and light curves of the pre-cataclysmic variables and modeling the reflection effects, we have derived their fundamental parameters. We demonstrate that the secondaries in these systems are consistent with evolutionary models for main-sequence stars and do not have the luminosity excesses characteristic of cool stars in young pre-cataclysmic variables. © 2012 Pleiades Publishing, Ltd

Effects of Bacillus Serine Proteases on the Bacterial Biofilms

© 2017 Olga Mitrofanova et al. Serratia marcescens is an emerging opportunistic pathogen responsible for many hospital-acquired infections including catheter-associated bacteremia and urinary tract and respiratory tract infections. Biofilm formation is one of the mechanisms employed by S. marcescens to increase its virulence and pathogenicity. Here, we have investigated the main steps of the biofilm formation by S. marcescens SR 41-8000. It was found that the biofilm growth is stimulated by the nutrient-rich environment. The time-course experiments showed that S. marcescens cells adhere to the surface of the catheter and start to produce extracellular polymeric substances (EPS) within the first 2 days of growth. After 7 days, S. marcescens biofilms maturate and consist of bacterial cells embedded in a self-produced matrix of hydrated EPS. In this study, the effect of Bacillus pumilus 3-19 proteolytic enzymes on the structure of 7-day-old S. marcescens biofilms was examined. Using quantitative methods and scanning electron microscopy for the detection of biofilm, we demonstrated a high efficacy of subtilisin-like protease and glutamyl endopeptidase in biofilm removal. Enzymatic treatment resulted in the degradation of the EPS components and significant eradication of the biofilms