The use of molecular-genetic and phytopathological methods to identify genes for effective leaf rust resistance in Aegilops accessions

Background. Identification of effective genes for disease resistance in resistant plant samples is the most important step toward recommending them for breeding. There are three main methods for such identification: hybridological analysis, phytopathological test, and DNA marking. The method of PCR markers is widely used in Russia to identify resistance genes in wheat relatives, including the genus Aegilops L. for resistance to leaf rust. From a theoretical viewpoint, the presence of a certain amplification fragment can hardly be interpreted as a definite proof of the presence of a resistance gene: during the species evolution, recombinations and mutations could occur, resulting in disturbance of the fragment’s presence and phenotypic expression of its connection with resistance. The purpose of this work was a comparison between molecular-genetic and phytopathological methods to identify leaf rust resistance genes Lr9 and Lr41 in three Aegilops species.Materials and methods. We identified leaf rust resistance genes Lr9 and Lr41 in forty Aegilops accessions using PCR with J13 and GDM35 primers, respectively. In the phytopathological test, the seedlings were infected with the pathogen population (avirulent to Lr9 and Lr41 genes) and the fungus clones virulent to the wheat line with the Lr9 gene.Results and conclusions. According to the data of molecular marking, the Lr41 gene was present in twelve Ae. tauschii Coss. accessions; Lr9 in four Ae. umbellulata Zhuk. accessions and four of Ae. biuncialis Vis. All accessions of Ae. tauschii, two of Ae. umbellulata, and three of Ae. biuncialis, possessing effective resistance genes according to the molecular testing, were susceptible to the pathogen population. For three Ae. umbellulata accessions resistant to the population, where DNA marking failed to identify an Lr9 gene, the presence of this gene was shown by a phytopathological test. Thus, there were significant differences in the postulation of effective Lr9 and Lr41 leaf rust resistance genes in Aegilops accessions after a phytopatological test and the use of DNA markers

Inheritance of effective juvenile leaf rust resistance in six accessions of Aegilops speltoides Tausch

Background. Leaf rust (causal agent: Puccinia triticina Erikss.) is a serious disease of bread wheat in all crop-growing regions. An environmentally safe and economically profitable method to protect plants is cultivation of resistant varieties. Their development requires searching for the forms carrying new genes of resistance. Despite the fact that more than 70 Lr genes have been described, only two (Lr39(41) and Lr47) are effective in the seedling stage over all the territory of the Russian Federation. Thus, expanding the set of effective leaf rust resistance genes is a high-priority task. An important source of such genes are wild relatives of Triticum aestivum L., including Aegilops L. species. Knowing genetic control of resistance in newly identified forms will help to avoid the transfer of the same alien resistance genes onto bread wheat. Materials and methods. Inheritance of effective juvenile leaf rust resistance was studied in 6 accessions of Ae. speltoides Tausch from the VIR collection. Crossings were carried out in the field of Pushkin and Pavlovsk Laboratories of VIR (St. Petersburg). Genetic control of resistance to the disease was analyzed in the following accessions of Ae. speltoides: k-1000 (Turkey), k-1015 (Afghanistan), k-1593 (Iraq), k-2279 (Iran), k-2753 and k-2819 (unknown origin). Results and conclusions. The analysis of segregation for seedling resistance to leaf rust in F2 и F3 from the crosses between the 6 studied accessions and the susceptible Ae. speltoides accession k-1596 showed that each of them possessed one dominant resistance gene. The absence of susceptible plants in hybrid populations from the crosses between resistant accessions testified to a tight linkage or, more likely, the identity of their genes associated with resistance. The identified resistance gene cannot be identical to Lr28, Lr35, Lr36 and Lr51, earlier introgressed into the T. aestivum genome from Ae. speltoides. Before the introgression of the newly identified gene, it is necessary to study its identity to Lr47 using the phytopathological test; the use of molecular markers for this purpose is little informative

Effective resistance to powdery mildew in Aegilops L. accessions

Background. Powdery mildew (Blumeria graminis (DC.) E.O. Speer f. sp. tritici Em. Marchal) is widespread and harmful in all regions of bread wheat cultivation. Severe development of powdery mildew leads to a decrease in the number and weight of grains. Growing resistant cultivars is the most environmentally friendly and economically profitable method to protect wheat from the disease. Development of such cultivars requires a search for new donors of effective genes controlling the resistance. To expand the genetic diversity of wheat for resistance to B. graminis, wild relatives of Triticum aestivum L., including Aegilops L. spp., are widely used. The aim of this work was to characterize seven Aegilops spp. for effective seedling and adult plant resistance to powdery mildew.Materials and methods. The material of the study consisted of 437 accessions representing 7 Aegilops spp. (Ae. speltoides Tausch, Ae. caudata L., Ae. biuncialis Vis., Ae. tauschii Coss., Ae. cylindrica Host, Ae. crassa Boiss. and Ae. ventricosa Tausch) from the collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR, St. Petersburg). Juvenile resistance was studied when the seedlings were inoculated with the agent of powdery mildew under controlled laboratory conditions; the adult plant resistance, after artificial inoculation of the plants and under natural infection in the fields of Pushkin and Pavlovsk Laboratories of VIR. Complex populations of the B. graminis agent were used for inoculation. The types of response to infection were scored 10 days after inoculation according to a conventional scale.Results and conclusions. As a result of the tests, susceptibility to powdery mildew was shown in all Aegilops accessions of the D-genome group; all the studied representatives of Ae. speltoides, Ae. caudata and Ae. biuncialis were highly resistant to powdery mildew

Metabolomic approach to search for fungal resistant forms of <i>Aegilops tauschii</i> Coss. from the VIR collection

Broadening of the genetic diversity of donors of resistance to biotic environmental factors is a challenging problem concerning Triticum L., which can be solved by using wild relatives of wheat, in particular, Aegilops tauschii Coss., in breeding programs. This species, believed to be the donor of D genome of common wheat (T. aestivum L.), is a source of some traits important for breeding. This greatly facilitates the possibility of crossing Ae. tauschii with common wheat. Aegilops L. species are donors of effective genes for resistance to fungal diseases in wheat. For instance, genes that determine resistance to rust agents in common wheat were successfully introgressed from Ae. tauschii into the genome of T. aestivum L. The aim of our study was to identify differences in metabolomic profiles of Ae. tauschii forms (genotypes), resistant or susceptible to such fungal pathogens as Puccinia triticina f. sp. tritici and Erysiphegraminis f. sp. tritici.These indicators may be used as biochemical markers of resistance. A comparative analysis of groups of Ae. tauschii accessions showed that metabolomic profiles of the forms with or without resistance to fungal pathogens differed significantly in the contents of nonproteinogenic amino acids, polyols, phytosterols, acylglycerols, mono- and oligosaccharides, glycosides, phenolic compounds (hydroquinone, kempferol), etc. This fact was consistent with the previously obtained data on the relationship between Fusarium resistance in oats (Avenasativa L.) and certain components of the metabolomic profile, such as acylglycerols, nonproteinogenic amino acids, galactinol, etc. Thus, our studies once again confirmed the possibility and effectiveness of the use of metabolomic analysis for screening the genetic diversity of accessions in the VIR collection, of Ae. tauschii in particular, in order to identify forms with a set of compounds in their metabolomic profile, which characterize them as resistant. Ae. tauschii accessions with a high content of pipecolic acids, acylglycerols, galactinol, stigmasterol, glycerol, azelaic and pyrogallic acids, campesterol, hydroquinone, etc., can be used for creating wheat and triticale cultivars with high resistance to fungal pathogens causing powdery mildew, brown rust, and yellow rust

First principle study on electronic structure of ferroelectric PbFe0.5Nb0.5O3

The full potential linearized augmented plane wave (FLAPW) method was used to study the crystal structure and electronic structure properties of PbFe0.5Nb0.5O3 (PFN). The optimized crystal structure, density of states, band structure and electron density distribution have been obtained to understand the ferroelectric behavior of PFN. From the density of states analysis, it is shown that there is a hybridization of Fe d - O p and Nb d - O p in ferroelectric PFN. This is consistent with the calculation of electronic band structure. This hybridization is responsible for the tendency to its ferroelectricity.Comment: 10 page

Эффективность регулятора роста растений Атоник Плюс на картофеле в условиях Московской области

The results of evaluating the effectiveness of the plant growth regulator Atonic Plus on potatoes as a stimulator of development, immunomodulator and protectant of the negative effects of pesticides in the crop protection system in the agro-climatic conditions of the Central region of the Russian Federation (Moscow region) are presented.In the extreme weather conditions of the growing season of 2010, the growth regulator Atonic Plus effectively demonstrated its qualities in the form of the formation of adaptability and anti-stress resistance in potato plants, providing an increase in yield relative to control by 1.8-7.1% and the quality of tubers is not only compared to the control, but also relative to the reference version. The combined use of a growth regulator with a fungicide contributed to an increase in the yield of standard potatoes in early and mid-late potato varieties by 2-2.5 times compared with the control.Представлены результаты оценки эффективности регулятора роста растений Атоник Плюс на картофеле в качестве стимулятора развития, иммуномодулятора и протектанта негативного действия пестицидов в системе защиты культуры в агроклиматических условиях Центрального региона РФ (Московская область). В экстремальных погодных условиях вегетационного периода 2010 года регулятор роста Атоник Плюс эффективно продемонстрировал свои качества в виде формирования у растений картофеля адаптивности и антистрессовой устойчивости, обеспечив прибавку урожая относительно контроля на 1,8-7,1% и качество клубней не только по сравнению с контролем, но и относительно эталонного варианта. Совместное применение регулятора роста с фунгицидом способствовало повышению урожая стандартного картофеля на раннем и среднепозднем сортах картофеля в 2-2,5 раза по сравнению с контролем

ОПРЕДЕЛЕНИЕ ТЕМПЕРАТУРНО-ВРЕМЕННЫХ ПАРАМЕТРОВ ВЫРАЩИВАНИЯ МОНОКРИСТАЛЛОВ β-BaB2O4 МОДИФИЦИРОВАННЫМ МЕТОДОМ ЧОХРАЛЬСКОГО

The aim of this work is to find of the mechanism the determination of optimal temperature-time mode of crystallization during the whole process of β-BaB2O4 crystal growth by modified Czochralski method. The phase diagram of the BaB2O4-Na2O system in the temperature range of β-BaB2O4 crystal growing is taken as a basis. The regularities of the constant geometric size crystals growth depending on the crystal-forming oxides concentration, the drawing and cooling rates and the slope of liquidus were established. The described algorithm of calculation allows to choose an optimum time-temperature crystallization mode during the whole growth process.Работа направлена на определение механизма нахождения оптимального температурно-временного режима кристаллизации на протяжении всего процесса выращивания QUOTE β-Ba B 2 O 4 β-BaB2O4 модифицированным методом Чохральского. За основу берется фазовая диаграмма системы BaB2О4-Na2O в температурном диапазоне выращивания кристаллов β-BaB2O4. Установлены закономерности получения кристаллов постоянного геометрического размера в зависимости от концентрации кристаллобразующих окислов, наклона кривой ликвидуса, скоростей вытягивания и охлаждения. Приведенный алгоритм расчета позволяет выбирать оптимальный температурно-временной режим кристаллизации на протяжении всего процесса выращивания

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation.

OBJECTIVES: To provide an accurate, web-based tool for stratifying patients with atrial fibrillation to facilitate decisions on the potential benefits/risks of anticoagulation, based on mortality, stroke and bleeding risks. DESIGN: The new tool was developed, using stepwise regression, for all and then applied to lower risk patients. C-statistics were compared with CHA2DS2-VASc using 30-fold cross-validation to control for overfitting. External validation was undertaken in an independent dataset, Outcome Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). PARTICIPANTS: Data from 39 898 patients enrolled in the prospective GARFIELD-AF registry provided the basis for deriving and validating an integrated risk tool to predict stroke risk, mortality and bleeding risk. RESULTS: The discriminatory value of the GARFIELD-AF risk model was superior to CHA2DS2-VASc for patients with or without anticoagulation. C-statistics (95% CI) for all-cause mortality, ischaemic stroke/systemic embolism and haemorrhagic stroke/major bleeding (treated patients) were: 0.77 (0.76 to 0.78), 0.69 (0.67 to 0.71) and 0.66 (0.62 to 0.69), respectively, for the GARFIELD-AF risk models, and 0.66 (0.64-0.67), 0.64 (0.61-0.66) and 0.64 (0.61-0.68), respectively, for CHA2DS2-VASc (or HAS-BLED for bleeding). In very low to low risk patients (CHA2DS2-VASc 0 or 1 (men) and 1 or 2 (women)), the CHA2DS2-VASc and HAS-BLED (for bleeding) scores offered weak discriminatory value for mortality, stroke/systemic embolism and major bleeding. C-statistics for the GARFIELD-AF risk tool were 0.69 (0.64 to 0.75), 0.65 (0.56 to 0.73) and 0.60 (0.47 to 0.73) for each end point, respectively, versus 0.50 (0.45 to 0.55), 0.59 (0.50 to 0.67) and 0.55 (0.53 to 0.56) for CHA2DS2-VASc (or HAS-BLED for bleeding). Upon validation in the ORBIT-AF population, C-statistics showed that the GARFIELD-AF risk tool was effective for predicting 1-year all-cause mortality using the full and simplified model for all-cause mortality: C-statistics 0.75 (0.73 to 0.77) and 0.75 (0.73 to 0.77), respectively, and for predicting for any stroke or systemic embolism over 1 year, C-statistics 0.68 (0.62 to 0.74). CONCLUSIONS: Performance of the GARFIELD-AF risk tool was superior to CHA2DS2-VASc in predicting stroke and mortality and superior to HAS-BLED for bleeding, overall and in lower risk patients. The GARFIELD-AF tool has the potential for incorporation in routine electronic systems, and for the first time, permits simultaneous evaluation of ischaemic stroke, mortality and bleeding risks. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF (NCT01090362) and for ORBIT-AF (NCT01165710)