The discovery of bidirectional microRNA transfer between two organisms during plant-microbe interactions and the ability of some fungal pathogens to absorb double-stranded RNA (dsRNA) or short interfering RNA (siRNA) from the environment provided an impetus for exploiting this mechanism in plant defense against pathogens. In this study, we investigated the role of conserved wheat microRNAs (miRNAs), miRNA408 and miRNA159, in inducing plant defense responses and suppressing the virulence of the phytopathogenic ascomycete fungus Parastagonospora nodorum, mediated by necrotrophic effectors (NEs) encoded by SnTox genes regulated by fungal transcription factors (TFs). The foliar spraying with in vitro synthesized siRNA408 and siRNA159 duplexes before inoculation with SnTox3-producing P. nodorum isolate increased wheat plant resistance to the SnB isolate and suppressed the pathogen growth and development. Most likely, silencing of the miRNA408 target genes TaCAT-2A, TaCAT-2B, and TaCLP1, and the miRNA159 target gene TaMYB65, led to the induction of a defense response of wheat plants against P. nodorum. This defense response was characterized by a decrease in the catalase activity, accumulation of hydrogen peroxide, activation of the expression of salicylic acid signaling pathway genes (TaWRKY13, TaPR1), and suppression of the expression of ethylene signaling pathway genes (TaEIN3, TaPR3). We demonstrated for the first time the ability of siRNA159 and siRNA408 to penetrate the mycelium of the pathogen P. nodorum and be involved in the cross-kingdom regulation of fungal genes to suppress the expression of some genes of NE (SnToxA, SnTox3) and fungal TFs (SnStuA). We predicted potential targets for wheat miRNA408 and miRNA159 in the P. nodorum transcriptome, making spray-induced gene silencing (SIGS) promising for use against this pathogen. These results provide valuable insights for studying the cross-kingdom transfer of plant miRNAs.

Abscisic acid (ABA) is not only important for plant responses to abiotic stresses, but also plays a key and multifaceted role in plant immunity. In this work, we analyzed the role of ABA in the development of resistance/susceptibility in the wheat (Triticum aestivum L.)–Stagonospora nodorum Berk. pathosystem, which includes the recognition of the necrotic effectors (NEs) of a pathogen by the corresponding wheat susceptibility genes. We studied the interaction of the S. nodorum SnB isolate, which produces two NEs, SnToxA and SnTox3, with three wheat genotypes having different combinations of the corresponding host susceptibility genes (Tsn1 and Snn3-B1). The results of this work on the gene expression and redox status of resistant and sensitive wheat genotypes treated with ABA show that ABA signaling is directed at inducing the resistance of wheat plants to S. nodorum SnB isolate through the activation of the early post-invasive defense genes TaERD15 and TaABI5. The induction of the expression of these genes leads to reactive oxygen species (ROS) accumulation during the early stage of infection, with the subsequent limitation of the pathogen’s growth. In the presence of a compatible interaction of SnTox3–Snn3-B1, ABA signaling is suppressed. On the contrary, in the presence of a compatible interaction of SnToxA–Tsn1, ABA signaling is activated, but the activity of the early post-invasive defense genes TaERD15 and TaABI5 is inhibited, and the expression of the NAC (NAM, ATAF1/2, and CUC2) transcription factor (TF) family genes TaNAC29 and TaNAC21/22 is induced. The TF genes TaNAC29 and TaNAC21/22 in the presence of SnToxA induce the development of the susceptibility of wheat plants to S. nodorum SnB, associated with a decrease in the oxidative burst during the early stage of infection. Thus, our study provides new data on the role of the NEs SnTox3 and SnToxA in manipulating ABA signaling in the development of the susceptibility of wheat to S. nodorum. Deepening our knowledge in this area will be instrumental for developing new strategies for breeding programs and will contribute to the development of environmentally friendly sustainable agriculture.

The SnTox1 effector is a virulence factor of the fungal pathogen Stagonospora nodorum (Berk.), which interacts with the host susceptibility gene Snn1 in a gene-for-gene manner and causes necrosis on the leaves of sensitive wheat genotypes. It is known that salicylic acid (SA), jasmonic acid (JA) and ethylene are the key phytohormones involved in plant immunity. To date, effectors of various pathogens have been discovered that can manipulate plant hormonal pathways and even use hormone crosstalk to promote disease development. However, the role of SnTox1 in manipulating hormonal pathways has not been studied in detail. We studied the redox status and the expression of twelve genes of hormonal pathways and two MAPK genes in six bread wheat cultivars sensitive and insensitive to SnTox1 with or without treatment by SA, JA and ethephon (ethylene-releasing agent) during infection with the SnTox1-producing isolate S. nodorum 1SP. The results showed that SnTox1 controls the antagonism between the SA and JA/ethylene signaling pathways. The SA pathway was involved in the development of susceptibility, and the JA/ethylene pathways were involved in the development of wheat plants resistance to the Sn1SP isolate in the presence of a SnTox1-Snn1 interaction. SnTox1 hijacked the SA pathway to suppress catalase activity, increase hydrogen peroxide content and induce necrosis formation; it simultaneously suppresses the JA and ethylene hormonal pathways by SA. To do this, SnTox1 reprogrammed the expression of the MAPK genes TaMRK3 and TaMRK6 and the TF genes TaWRKY13, TaEIN3 and TaWRKY53b. This study provides new data on the role of SnTox1 in manipulating hormonal pathways and on the role of SA, JA and ethylene in the pathosystem wheat S. nodorum.

Cytokinins (CKs) and abscisic acid (ABA) play an important role in the life of both plants and pathogenic fungi. However, the role of CKs and ABA in the regulation of fungal growth, development and virulence has not been sufficiently studied. We compared the ability of two virulent isolates (SnB and Sn9MN-3A) and one avirulent isolate (Sn4VD) of the pathogenic fungus Stagonospora nodorum Berk. to synthesize three groups of hormones (CKs, ABA and auxins) and studied the effect of exogenous ABA and zeatin on the growth, sporulation and gene expression of necrotrophic effectors (NEs) and transcription factors (TFs) in them. Various isolates of S. nodorum synthesized different amounts of CKs, ABA and indoleacetic acid. Using exogenous ABA and zeatin, we proved that the effect of these hormones on the growth and sporulation of S. nodorum isolates can be opposite, depends on both the genotype of the isolate and on the concentration of the hormone and is carried out through the regulation of carbohydrate metabolism. ABA and zeatin regulated the expression of fungal TF and NE genes, but correlation analysis of these parameters showed that this effect depended on the genotype of the isolate. This study will contribute to our understanding of the role of the hormones ABA and CKs in the biology of the fungal pathogen S. nodorum.

Beneficial endophytic bacteria can suppress the development of insect pests through direct antagonism, with the help of metabolites, or indirectly by the induction of systemic resistance through the regulation of hormonal signaling pathways. Lipopeptides are bacterial metabolites that exhibit direct antagonistic activity against many organisms, including insects. Also, lipopeptides are able to trigger induced systemic resistance (ISR) in plants against harmful organisms, but the physiological mechanisms of their action are just beginning to be studied. In this work, we studied ten strains of bacteria isolated from the tissues of wheat and potatoes. Sequencing of the 16S rRNA gene showed that all isolates belong to the genus Bacillus and to two species, B. subtilis and B. velezensis. The genes for lipopeptide synthetase – surfactin synthetase (Bs_srf ), iturin synthetase (Bs_ituA, Bs_ituB) and fengycin synthetase (Bs_fenD) – were identified in all bacterial isolates using PCR. All strains had high aphicidal activity against the Greenbug aphid (Schizaphis graminum Rond.) due to the synthesis of lipopeptides, which was proven using lipopeptiderich fractions (LRFs) isolated from the strains. Endophytic lipopeptide-synthesizing strains of Bacillus spp. indirectly affected the viability of aphids, the endurance of plants against aphids and triggered ISR in plants, which manifested itself in the regulation of oxidative metabolism and the accumulation of transcripts of the Pr1, Pr2, Pr3, Pr6 and Pr9 genes due to the synthesis of lipopeptides, which was proven using LRF isolated from three strains: B. subtilis 26D, B. subtilis 11VM, and B. thuringiensis B-6066. We have for the first time demonstrated the aphicidal effect of fengycin and the ability of the fengycin-synthesizing strains and isolates, B. subtilis Ttl2, Bacillus sp. Stl7 and B. thuringiensis B-6066, to regulate components of the pro-/antioxidant system of aphid-infested plants. In addition, this work is the first to demonstrate an elicitor role of fengycin in triggering a systemic resistance to S. graminum in wheat plants. We have discovered new promising strains and isolates of endophytes of the genus Bacillus, which may be included in the composition of new biocontrol agents against aphids. One of the criteria for searching for new bacteria active against phloem-feeding insects can be the presence of lipopeptide synthetase genes in the bacterial genome.

This article studies the deformation resistance of high-temperature superconducting (HTSC) tapes for various parameters of deformation. The four-contact method has been used to measure the critical current in specimens deformed on indenters with diameters of 5–20 mm by tensile forces up to 200 N. The damage to the superconducting layer and local superconducting properties of mechanically impacted specimens have been investigated using scanning electron microscopy and scanning Hall magnetometry.

Recently, several RNA interference-based disease prevention mechanisms using small RNAs have been used to protect crops in some countries. Plants secrete small RNAs that directly or indirectly inhibit the virulence of pathogens. In this work, we studied the effect of three wheat microRNAs (miR159, miR166 and miR408) synthesized in vitro on the growth and sporulation of the pathogenic fungus Stagonospora nodorum, as well as on the expression of the genes of the necrotrophic effectors (NEs) S. nodorum SnToxA and SnTox3 (which determine the virulence of the pathogen) and the fungal transcription factors (TFs) Pf2, StuA, Con7 regulating the transcription of NE genes. It was shown that the addition of microRNAs in various concentrations into the fungal cultivation medium affected the growth of colonies and sporulation of the pathogen. miR166 had the greatest impact on these parameters. Using gene-specific primers, PCR analysis was carried out, which showed that the effect of microRNA on the expression of the genes encoding NEs and TFs of the pathogenic fungus S. nodorum depended on the type and concentration of microRNA in the medium. Thus, 0.5 ng/μl of ssRNA408 reduced the expression of all the studied NEs and TFs genes on the 7th day of cultivation. Further comprehensive studies of the mechanisms of cross-species regulation using miRNAs may help in the development of new pesticides for modern agriculture.

The greenbug aphid Schizaphis graminum causes significant damage to wheat crops, so increasing plant resistance against aphids is one of the primary tasks. It has been shown that colonization by aphids to trigger both jasmonate/ethylene- and salicylate-dependent defense responses in plants. Ethylene is produced when insects attack. It has been suggested that ethylene plays an important role in inducing resistance against pests, but the mechanism of action of ethylene is not fully understood. In this work, the role of ethylene in the induction of hormonal signaling pathways in wheat plants during the development of resistance against the greenbug aphid S. graminum was revealed by treating plants with the ethylene receptor inhibitor 1-MCP (1-methylcyclopropene) or an ethylene precursor (ethephon - ET). Analysis of the transcriptional activity of the genes of the hormonal signaling pathways ethylene, salicylic acid (SA), jasmonic acid (JA), cytokinins (CK) and abscisic acid (ABA) showed that treatment of plants with ET activated the genes SA-, JA-, ABA- and ethylene- signaling pathways (TaEIN3, TaERF1, TaWRKY53b, TaPR3, TaPR1, TaWRKY13, TaPR6, TaABI5, TaABAI and TaNCED).The study of the endogenous level of phytohormones using enzyme immunoassay showed that treatment of plants with ET induced the accumulation of ABA and indolylacetic acid (IAA), but not the content of CK after the plants were colonized by aphids. Thus, the positive effect of ethylene on the resistance of wheat plants against the greenbug aphid was proven through the synergistic effect of ethylene with SA and JA and the positive or negative regulation of the activity of the components of these signaling pathways by the phytohormones CK, ABA and IAA.

В данной работе методом вибрационной магнитометрии измерялась намагниченность промышленного многоволоконного круглого проводника MgB2 (Columbus Superconductors) и соответствующие петли гистерезиса при различных температурах в диапазоне 5–45 К и магнитных полях до 5 Тл. Направление приложенного магнитного поля варьировалось от 0 до 90 градусов по отношению к оси проводника. Ферромагнитный вклад Fe и Ni (оболочка из никелевого сплава – монель) был вычтен, и были получены изолированные петли намагниченности из-за диамагнитного вклада сверхпроводящей фазы MgB2. Зависимости Jc (H), а также значения гистерезисных потерь рассчитывались по кривым гистерезиса для различных температур. Полученные данные обсуждаются с точки зрения анизотропии сверхпроводящих свойств MgB2 и влияния геометрического фактора размагничивания на величину намагниченности. In this study, the magnetization of an industrial multi-strand round MgB2 cable (Columbus Superconductors) and the corresponding hysteresis loops were measured using the method of vibrational magnetometry at various temperatures ranging from 5 to 45 K and magnetic fields up to 5 T. The direction of the applied magnetic field varied from 0 to 90 degrees with respect to the cable axis. The ferromagnetic contribution of Fe and Ni (the nickel alloy sheath) was subtracted, and the magnetization loops due to the diamagnetic contribution of the MgB2 superconducting phase were obtained. Dependencies of J c (H), as well as the values of hysteresis losses, were calculated from the hysteresis curves at different temperatures. The obtained data are discussed in terms of the anisotropy of the superconducting properties of MgB2 and the influence of the geometric demagnetization factor on the magnitude of magnetization.

The use of biocontrol agents based on endophytic bacteria against phloem-feeding insects is limited by a lack of knowledge and understanding of the mechanism of action of the endophyte community that makes up the plant microbiome. In this work, the mechanisms of the additive action of endophytic strains B. subtilis 26D and B. subtilis 11VM on the resistance of bread spring wheat against greenbug aphid Schizaphis graminum, was studied. It was shown that B. subtilis 26D secreted lipopeptide surfactin and phytohormones cytokinins, and B. subtilis 11VM produced iturin and auxins into the cultivation medium. Both strains and their lipopeptide-rich fractions showed direct aphicidal activity against greenbug aphid. For the first time, it was shown that B. subtilis 26D and B. subtilis 11VM in the same manner, as well as their lipopeptide-rich fractions, activated the expression of salicylate- and ethylene-dependent PR genes, and influenced plant redox metabolism, which led to an increase in plant endurance against aphids. The composition of endophytic strains B. subtilis 26D + B. subtilis 11VM had an additive effect on plant resistance to aphids due to an increase in the number of endophytic bacterial cells, and, as well as due to the synergistic effect of their mixture of lipopeptides − surfactin + iturin, both on the aphid mortality and on the expression of PR1 and PR3 genes. All these factors can be the reason for the observed increase in the growth of plants affected by aphids under the influence of B. subtilis 26D and B. subtilis 11VM, individually and in composition. The study demonstrates the possibility of creating in the future an artificial composition to enhance plant microbiome with endophytic bacteria, which combines growth-promoting and plant immunity stimulating properties against phloem-feeding insects. This direction is one of the most promising approaches to green pesticide discovery in the future.

High-temperature superconducting magnets are a system with a complex configuration. In the process of creating such systems, HTSC tapes can be subject to mechanical damage, which leads to a deterioration in the transport characteristics of the tape. This paper presents the results of experimental studies of the effect of mechanical stresses on the transport characteristics of the second-generation HTSC tapes. The volt-ampere characteristics of various samples of second-generation HTSC tapes were measured during their winding on cylindrical formers of various diameters. Winding was carried out at the angles of 22° and 40° relative to the former axis with a force from 10 to 20 N. Different winding options were compared and the optimal set of winding configurations corresponding to the minimum degradation of the critical current of the tape was determined. Scanning Hall magnetometry is used to determine the regions of localization of defects arising at various winding options. All measurements were carried out at the boiling point of liquid nitrogen. The obtained data made it possible to calculate the area of flow of the longitudinal and transverse components of the current in each individual case.

Bacillus subtilis 26D is a plant growth-promoting endophytic bacteria capable of inducing systemic resistance through the priming mechanism, which includes plant genome reprogramming and the phenomenon of RNA interference (RNAi) and microRNA (miRNAs). The phloem-feeding insect bird cherry-oat aphid Rhopalosiphum padi L. is a serious pest that causes significant damage to crops throughout the world. However, the function of plant miRNAs in the response to aphid infestation remains unclear. The results of this work showed that B. subtilis 26D stimulated aphid resistance in wheat plants, inducing the expression of genes of hormonal signaling pathways ICS, WRKY13, PR1, ACS, EIN3, PR3, and ABI5. In addition, B. subtilis 26D activated the RNAi mechanism and regulated the expression of nine conserved miRNAs through activation of the ethylene, salicylic acid (SA), and abscisic acid (ABA) signaling pathways, which was demonstrated by using treatments with phytohormones. Treatment of plants with SA, ethylene, and ABA acted in a similar manner to B. subtilis 26D on induction of the expression of the AGO4, AGO5 and DCL2, DCL4 genes, as well as the expression of nine conserved miRNAs. Different patterns of miRNA expression were found in aphid-infested plants and in plants treated with B. subtilis 26D or SA, ethylene, and ABA and infested by aphids, suggesting that miRNAs play multiple roles in the plant response to phloem-feeding insects, associated with effects on hormonal signaling pathways, redox metabolism, and the synthesis of secondary metabolites. Our study provides new data to further elucidate the fine mechanisms of bacterial-induced priming. However, further extensive work is needed to fully unravel these mechanisms.

The article presents the results obtained from measuring the magnetization of and hysteresis loss in a multifilament MgB2 superconducting wire (produced by ASG Superconductors) for magnetic field applied in two directions: in parallel and perpendicular to the conductor axis. The measurement temperatures were varied in the range of 5–45 K. The MgB2 superconducting fraction magnetization curves were obtained by subtracting the magnetization of the wire ferromagnetic matrix measured at temperature T = 45 K, which is above the superconductor critical temperature Tc , from the magnetization value of the entire specimen. From these magnetization curves, the dependences of the hysteresis energy loss on the external magnetic field strength Qh(Н) were obtained. It is shown that, with the field oriented perpendicular to the MgB2 wire axis and at the external field characteristic values, the hysteresis loss is twice as large. A method for calculating the hysteresis loss in a superconducting wire and methods for reducing it are proposed. The obtained results can be used to optimize NMR and MRI facilities, superconducting motors and generators made using MgB2 superconducting wire produced by ASG Superconductors.

Virulence factors of the pathogen Stagonospora nodorum Berk. are numerous necrotrophic effectors (NEs) (SnTox), which interact with the products of host susceptibility genes (Snn), causing the development of the disease. In this study, 55 accessions of bread spring and winter wheat were screened for sensitivity to NEs SnToxA, SnTox1, and SnTox3 using different isolates of S. nodorum. In the studied panel of wheat, 47 accessions were modern commercial cultivars grown in Russia and 8 cultivars were historic wheat accessions from the N. I. Vavilov Institute of Plant Genetic Resources in Russia. In general, our wheat panel differed from other wheat collections with available data in that it was less sensitive to SnToxA and SnTox3, and more sensitive to SnTox1. Six sources of strong SNB resistance were identified in our wheat panel. In addition, during the study, wheat cultivars were identified as appropriate objects in which to study the different effects of SnTox-Snn interactions, which is important for marker-assisted selection for SNB resistance. The current study has shown, for the first time, that the expression level of Snn1 and Tsn1 susceptibility genes and the disease severity of the different wheat cultivars are interconnected. Future work should focus on the deep characterization of SnTox-Snn interactions at the molecular level.

Background: Currently, the role of microRNAs in plant immune responses is being actively studied. Thus, our aim was to research the effect of Stagonospora nodorum (Berk.) NEs SnToxA and SnTox3 on the expression of miRNAs involved in the wheat–S. nodorum interaction and to determine the role of phytohormones in this process. Methods: The expressions of nine conserved microRNAs were studied by quantitative real-time polymerase chain reaction in three different wheat genotypes of bread spring wheat (Triticum aestivum L.) infected with S. nodorum. Phytohormone treatments (trans-zeatin, 2-chloroethylphosphonic acid (etefone is the chemical precursor of ethylene), and salicylic acid) were applied. The results were compared with disease symptoms, the redox status of plants, and the expression of fungal necrotrophic effector (NE) genes of SnToxA and SnTox3 and genes of SnPf2, SnStuA, alongside SnCon7 transcription factors (TFs). Results: Salicylic acid (SA) and cytokinins (CK) are involved in the development of defense reactions in wheat plants against S. nodorum, by regulating the expression of fungal NEs and TFs genes, inducing an oxidative burst in all three wheat genotypes. Moreover, ethylene enhanced the virulence of the pathogen by increasing the expression of fungal NE and TF genes, thereby resulting in a decrease in the generation of reactive oxygen species in all three cultivars. The nine miRNAs played a role in the development of wheat resistance against S. nodorum. NE SnTox3 mainly suppressed the expression of three miRNAs: miR159, miR393, and miR408, while NE SnToxA suppressed miR166 expression. Conversely, treatment with CK and SA increased the expression of miR159 and miR408; treatment with CK increased the expression of miR393 and miR166. Ethylene inhibited the expression of miR159, miR408, miR393, and miR166. Suppression of miP159 expression by NE SnTox3 was most likely associated with the activation of the ethylene signaling pathway. NEs SnToxA and SnTox3 suppressed the expression of miR408, whose role most likely consisted of inhibiting the catalase activity, via SA and CK regulation. In addition, NE SnToxA hijacked the SA signaling pathway and manipulated it for fungal growth and development. Fungal TFs SnPf2 and SnStuA could be involved in the regulation of these processes indirectly through the regulation of the expression of NE genes. Conclusions: The results of this work show, for the first time, the role of microRNAs in the development of wheat resistance against S. nodorum and the effect of S. nodorum NEs SnToxA and SnTox3 on the activity of plant microRNAs.

The effect of irradiation with Cu + ions with an energy of E = 6.3 eV on the crystal structure and critical characteristics of high-temperature copper-based superconductors in the regime of radiation defect formation has been studied. The degradation of the superconducting properties and the growth of the lattice parameters and the magnitude of the relative stresses due to disorder along the c axis with increasing fluence up to the complete disappearance of the superconducting properties at the fluence F = 1.5 × 10 14 cm –2 are shown.

The causative agent of wheat blotch the pathogenic fungus Stagonospora nodorum Berk. is one of the most harmful wheat pathogens. Necrotrophic effectors (NE) have been identified in the pathogen, which ensure the virulence of S. nodorum strains to the host plant, in the genome of which the dominant susceptibility gene corresponding to the effector is present. Currently, the study of the regulation of the genes expression responsible for virulence is becoming an increasingly important objective. Recently, the role of various transcription factors (TFs) in the regulation of effector genes expression in the fungal pathogens has been established. However, new data are emerging on the effect of hormones on the growth, development, and virulence of pathogenic fungi. Therefore, the aim of our research was to study the effect of cytokinins (CK) and abscisic acid (ABA) on the expression of the NE SnToxA, SnTox1, SnTox3, and TF SnStuA, SnPf2, and SnCon7 genes in various isolates of the pathogen S. nodorum SnB, Sn4VD, Sn9MN-3A, and Sn1SP, which differ in virulence. Our results showed that the intensity of NE and TF gene expression was associated with the aggressiveness of the pathogen isolate, and TF gene expression correlated with NE gene expression. The highest expression of NE genes was found in SnB and Sn1SP isolates. When the hormones ABA or CK were added to the cultivation medium, they mainly had a positive effect on the expression of the NE and TF genes. ABA treatment increased the expression of all three NE genes SnToxA, SnTox3, and SnTox1. Treatment with CK had a positive effect only on the expression of the SnTox3 gene. Based on the results, an assumption was made about the indirect effect of hormones on virulence factors through the regulation of growth and metabolism of fungi.