First report of Medicago trirhavirus 1 infecting alfalfa in Washington State, USA.

The first tri-segmented viruses in the family Rhabdoviridae were recently discovered by exploring publicly available plant datasets in several hosts, including alfalfa (Medicago sativa L.) (Bejerman et al. 2023). They were classified in a novel genus "Trirhavirus" within the family Rhabdoviridae. The trirhavirus identified in alfalfa was named Medicago trirhavirus 1 (MeTRV1). Here we report the first confirmation of MeTRV1 in commercial alfalfa fields in Washington State, USA. Samples were collected in 2019-2021 in Benton and Grant Counties, WA. The alfalfa leaves in which the virus was detected displayed irregular chlorotic spotting (Fig.1). Total RNA extraction, library preparation, high throughput sequencing, and bioinformatics analysis were performed as described in Nemchinov et al (2023). Raw reads were trimmed with Trimmomatic 0.39 (Bolger at al. 2014). SPAdes 3.15.5 (Bankevich et al. 2012) was used for assembly. MeTRV1 was identified in four plants out of 100 tested and three complete RNA segments were recovered from one of them. For clarity, the virus found in the alfalfa field samples was designated MeTRV1-Wa. De novo assembly resulted in three contigs, which, when subjected to BLASTn analyses, aligned to the respective RNA segments of MeTRV1. The first contig was 6,498 nucleotides (nts)-long, 99.4% identical to RNA1 of MeTRV1 (BK064256.1), and 5,922 reads mapped to it (coverage 125x). RNA1 of MeTRV1-Wa encoded a protein 2,040 amino acid (aa)-long that aligned with protein L of MeTRV1 (DBA36559.1, 99.8%). The second contig was 4,014 nts-long and 95.2% identical to the RNA2 of MetRV1 (BK064257.1) with 1,751 reads mapping (coverage 59x). It contained four open reading frames (ORFs) encoding proteins N (445 aa, 99.8%, DBA36560.1); P2 (343 aa, 99.4%, DBA36561.1); P3 (183 aa, 99.4%, DBA36562.1); and P4 (72 aa, 98.6%, DBA36563.1). Altogether, 4,653 reads mapped to the third contig (coverage 131x) that was 4,889 nts-long and 99.1% identical to the RNA 3 segment of MeTRV1 (BK064258.1). RNA3 of MeTRV1-Wa encoded four proteins: P6 (274 aa, 100%, DBA36565.1); P7 (189 aa, 99.5%, DBA36566.1); P8 (514 aa, 99 %, DBA36567.1); and P5 (303 aa, 99.7%, DBA36564.1). The 5' trailer of each RNA segment had a nearly identical 24 nts at the end. Genomic organization of the MeTRV1-Wa and the locations of its ORFs are shown in Fig.2. To confirm the virus's presence, two sets of primers were designed based on the predicted sequence of the viral RNA 3 segment. The correct-size products were amplified in RT-PCR assays with RNA extracted from infected plants (Fig.3) and verified by Sanger sequencing. Besides MeTRV1-Wa, sequences of the following viruses known to cause symptoms in alfalfa were identified in the same library: alfalfa mosaic virus, bean leafroll virus, lucerne transient streak virus, and pea streak virus. Thus, the observed symptomatology may not be clearly attributed to MeTRV1-Wa due to coinfecting organisms. However, a possible association of the disease symptoms with the virus presence could be suggested based on comparison with both asymptomatic and symptomatic plants negative for MeTRV1-Wa (Fig.1). Since plant rhabdoviruses are recognized as a cause of economic losses in alfalfa and other major crops and are transmitted by insects (Bejerman et al. 2011, 2015; Jackson et al. 2005; Man and Dietzgen 2014), this first experimental confirmation of the occurrence of the new virus in the U.S. alfalfa is important for understanding its origin, distribution, and pathogenic potential.

Genetic Diversity for Effective Resistance in Wheat Landraces from Ethiopia and Eritrea to Fungal Diseases and Toxic Aluminum Ions.

To reveal genetic diversity for effective resistance to five foliar diseases and toxic aluminum ions, the entire collection of wheat species from the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) originating from Ethiopia and Eritrea were studied regarding their traits. The collection contains 509 samples of four wheat species (Triticum aestivum-122 samples; T. aethiopicum-340 samples; T. polonicum-6 samples; and T. dicoccum-41 samples). The majority of accessions are new entries of landraces added to the Vavilov collection as a result of the Russian-Ethiopian expedition in 2012. Wheat seedlings were inoculated with causal agents of leaf rust (Pt), powdery mildew (Bgt), Septoria nodorum blotch (SNB), and dark-brown leaf spot blotch (HLB). The types of reaction and disease development were assessed to describe the levels of resistance. All samples of T. aethiopicum were also screened for seedling and adult resistance to Pt, Bgt, and yellow rust (Pst) under field conditions after double inoculation with the corresponding pathogens. To study tolerance to abiotic stress, seedlings were grown in a solution of Al3+ (185 µM, pH 4,0) and in water. The index of root length was used to characterize tolerance. Seedlings belonging to only two accessions out of those studied-k-68236 of T. aethiopicum and k-67397 of T. dicoccum-were resistant to Pt at 20 °C but susceptible at 25 °C. Specific molecular markers closely linked to the five genes for Pt resistance effective against populations of the pathogen from the northwestern region of Russia were not amplified in these two entries after PCR with corresponding primers. Four entries of T. dicoccum-k-18971, k-18975, k-19577, and k-67398-were highly resistant to Bgt. All samples under study were susceptible to HLB and SNB. Under field conditions, 15% of the T. aethiopicum samples were resistant to Pst, both at the seedling and the flag leaf stages, but all were susceptible to the other diseases under study. Among the evaluated samples, 20 entries of T. aestivum, 1 of T. polonicum (k-43765), and 2 of T. dicoccum (k-18971, k-67397) were tolerant to aluminum ions. The identified entries could be valuable sources for the breeding of T. aestivum and other wheats for resistance to biotic and abiotic stresses.

Complete genome sequence of alfalfa-associated picorna-like virus 2.

We have previously reported on the detection of an unknown picorna-like virus in alfalfa samples. The exact host of the virus was unclear due to its similarity to the members of Iflaviridae family, which typically infect arthropods. The virus was provisionally named alfalfa-associated picorna-like virus 2. Here, we report a complete genomic sequence of the virus.

Alfalfa vein mottling virus, a novel potyvirid infecting Medicago sativa L.

BACKGROUND: We have recently identified a novel virus detected in alfalfa seed material. The virus was tentatively named alfalfa-associated potyvirus 1, as its genomic fragments bore similarities with potyvirids. In this study, we continued investigating this novel species, expanding information on its genomic features and biological characteristics. METHODS: This research used a wide range of methodology to achieve end results: high throughput sequencing, bioinformatics tools, reverse transcription-polymerase chain reactions, differential diagnostics using indicator plants, virus purification, transmission electron microscopy, and others. RESULTS: In this study, we obtained a complete genome sequence of the virus and classified it as a tentative species in the new genus, most closely related to the members of the genus Ipomovirus in the family Potyviridae. This assumption is based on the genome sequence and structure, phylogenetic relationships, and transmission electron microscopy investigations. We also demonstrated its mechanical transmission to the indicator plant Nicotiana benthamiana and to the natural host Medicago sativa, both of which developed characteristic symptoms therefore suggesting a pathogenic nature of the disease. CONCLUSIONS: Consistent with symptomatology, the virus was renamed to alfalfa vein mottling virus. A name Alvemovirus was proposed for the new genus in the family Potyviridae, of which alfalfa vein mottling virus is a tentative member.

Composition of the alfalfa pathobiome in commercial fields.

Through the recent advances of modern high-throughput sequencing technologies, the "one microbe, one disease" dogma is being gradually replaced with the principle of the "pathobiome". Pathobiome is a comprehensive biotic environment that not only includes a diverse community of all disease-causing organisms within the plant but also defines their mutual interactions and resultant effect on plant health. To date, the concept of pathobiome as a major component in plant health and sustainable production of alfalfa (Medicago sativa L.), the most extensively cultivated forage legume in the world, is non-existent. Here, we approached this subject by characterizing the biodiversity of the alfalfa pathobiome using high-throughput sequencing technology. Our metagenomic study revealed a remarkable abundance of different pathogenic communities associated with alfalfa in the natural ecosystem. Profiling the alfalfa pathobiome is a starting point to assess known and identify new and emerging stress challenges in the context of plant disease management. In addition, it allows us to address the complexity of microbial interactions within the plant host and their impact on the development and evolution of pathogenesis.

Pentylenetetrazole-Induced Seizures Are Increased after Kindling, Exhibiting Vitamin-Responsive Correlations to the Post-Seizures Behavior, Amino Acids Metabolism and Key Metabolic Regulators in the Rat Brain.

Epilepsy is characterized by recurrent seizures due to a perturbed balance between glutamate and GABA neurotransmission. Our goal is to reveal the molecular mechanisms of the changes upon repeated challenges of this balance, suggesting knowledge-based neuroprotection. To address this goal, a set of metabolic indicators in the post-seizure rat brain cortex is compared before and after pharmacological kindling with pentylenetetrazole (PTZ). Vitamins B1 and B6 supporting energy and neurotransmitter metabolism are studied as neuroprotectors. PTZ kindling increases the seizure severity (1.3 fold, p < 0.01), elevating post-seizure rearings (1.5 fold, p = 0.03) and steps out of the walls (2 fold, p = 0.01). In the kindled vs. non-kindled rats, the post-seizure p53 level is increased 1.3 fold (p = 0.03), reciprocating a 1.4-fold (p = 0.02) decrease in the activity of 2-oxoglutarate dehydrogenase complex (OGDHC) controlling the glutamate degradation. Further, decreased expression of deacylases SIRT3 (1.4 fold, p = 0.01) and SIRT5 (1.5 fold, p = 0.01) reciprocates increased acetylation of 15 kDa proteins 1.5 fold (p < 0.01). Finally, the kindling abrogates the stress response to multiple saline injections in the control animals, manifested in the increased activities of the pyruvate dehydrogenase complex, malic enzyme, glutamine synthetase and decreased malate dehydrogenase activity. Post-seizure animals demonstrate correlations of p53 expression to the levels of glutamate (r = 0.79, p = 0.05). The correlations of the seizure severity and duration to the levels of GABA (r = 0.59, p = 0.05) and glutamate dehydrogenase activity (r = 0.58, p = 0.02), respectively, are substituted by the correlation of the seizure latency with the OGDHC activity (r = 0.69, p < 0.01) after the vitamins administration, testifying to the vitamins-dependent impact of the kindling on glutamate/GABA metabolism. The vitamins also abrogate the correlations of behavioral parameters with seizure duration (r 0.53-0.59, p < 0.03). Thus, increased seizures and modified post-seizure behavior in rats after PTZ kindling are associated with multiple changes in the vitamin-dependent brain metabolism of amino acids, linked to key metabolic regulators: p53, OGDHC, SIRT3 and SIRT5.

Characterization of the seed virome of alfalfa (Medicago sativa L).

BACKGROUND: Seed transmission of plant viruses can be important due to the role it plays in their dissemination to new areas and subsequent epidemics. Seed transmission largely depends on the ability of a virus to replicate in reproductive tissues and survive during the seed maturation process. It occurs through the infected embryo or mechanically through the contaminated seed coat. Alfalfa (Medicago sativa L.) is an important legume forage crop worldwide, and except for a few individual seedborne viruses infecting the crop, its seed virome is poorly known. The goal of this research was to perform initial seed screenings on alfalfa germplasm accessions maintained by the USDA ARS National Plant Germplasm System in order to identify pathogenic viruses and understand their potential for dissemination. METHODS: For the detection of viruses, we used high throughput sequencing combined with bioinformatic tools and reverse transcription-polymerase chain reactions. RESULTS: Our results suggest that, in addition to common viruses, alfalfa seeds are infected by other potentially pathogenic viral species that could be vertically transmitted to offspring. CONCLUSIONS: To the best of our knowledge, this is the first study of the alfalfa seed virome carried out by HTS technology. This initial screening of alfalfa germplasm accessions maintained by the NPGS showed that the crop's mature seeds contain a broad range of viruses, some of which were not previously considered to be seed-transmitted. The information gathered will be used to update germplasm distribution policies and to make decisions on the safety of distributing germplasm based on viral presence.

Snake River alfalfa virus, a persistent virus infecting alfalfa (Medicago sativa L.) in Washington State, USA.

Here we report an occurrence of Snake River alfalfa virus (SRAV) in Washington state, USA. SRAV was recently identified in alfalfa (Medicago sativa L.) plants and western flower thrips in south-central Idaho and proposed to be a first flavi-like virus identified in a plant host. We argue that the SRAV, based on its prevalence in alfalfa plants, readily detectable dsRNA, genome structure, presence in alfalfa seeds, and seed-mediated transmission is a persistent new virus distantly resembling members of the family Endornaviridae.

Effective Resistance to Four Fungal Foliar Diseases in Samples of Wild Triticum L. Species from the VIR (N.I. Vavilov All-Russian Institute of Plant Genetic Resources) Collection: View from Vavilov's Concepts of Plant Immunity.

To identify new sources of effective resistance to four foliar diseases of wheat, 173 accessions of four wheat species, Triticum boeoticum, T. urartu, T. araraticum, and T. dicoccoides, from the VIR collection were tested at the juvenile and adult growth stages for resistance to leaf rust (Pt = Puccinia triticina), powdery mildew (Bgt = Blumeria graminis tritici), Septoria nodorum blotch (SNB), and dark-brown leaf spot blotch (HLB = Helminthospjrium leaf blotch). The accessions included new additions to the collection, some old samples that had never been tested before, as well as earlier tested samples noted for high levels of juvenile resistance to some fungal diseases. Natural populations of Puccinia triticina and Blumeria graminis f. sp. tritici, mixture of Parastagonospora nodorum and Bipolaris sorokiniana isolates were used to inoculate and to evaluate resistance to Pt, Bgt, SNB, and HLB, respectively. Two samples of T. boeoticum, three of T. urartu, and one of T. araraticum were resistant to leaf rust at both tested stages. Further tests (phytopathological and molecular analyses) excluded Lr9, Lr19, Lr24, Lr41, or Lr47 as single genes controlling resistance; hence, these accessions likely carry new effective leaf rust resistance genes. High level of Bgt resistance was identified in three entries of T. boeoticum, one of T. araraticum, and eleven of T. dicoccoides. All tested accessions were susceptible to HLB and SNB at both tested stages. Accessions identified as resistant are valuable plant material for introgressive hybridization in bread and durum wheat breeding. The results are discussed in the context of N.I. Vavilov's concept of crop origin and diversity, and the laws of plant natural immunity to infectious diseases.

The Brain Protein Acylation System Responds to Seizures in the Rat Model of PTZ-Induced Epilepsy.

Abnormal energy expenditure during seizures and metabolic regulation through post-translational protein acylation suggest acylation as a therapeutic target in epilepsy. Our goal is to characterize an interplay between the brain acylation system components and their changes after seizures. In a rat model of pentylenetetrazole (PTZ)-induced epilepsy, we quantify 43 acylations in 29 cerebral cortex proteins; levels of NAD+; expression of NAD+-dependent deacylases (SIRT2, SIRT3, SIRT5); activities of the acyl-CoA-producing/NAD+-utilizing complexes of 2-oxoacid dehydrogenases. Compared to the control group, acylations of 14 sites in 11 proteins are found to differ significantly after seizures, with six of the proteins involved in glycolysis and energy metabolism. Comparing the single and chronic seizures does not reveal significant differences in the acylations, pyruvate dehydrogenase activity, SIRT2 expression or NAD+. On the contrary, expression of SIRT3, SIRT5 and activity of 2-oxoglutarate dehydrogenase (OGDH) decrease in chronic seizures vs. a single seizure. Negative correlations between the protein succinylation/glutarylation and SIRT5 expression, and positive correlations between the protein acetylation and SIRT2 expression are shown. Our findings unravel involvement of SIRT5 and OGDH in metabolic adaptation to seizures through protein acylation, consistent with the known neuroprotective role of SIRT5 and contribution of OGDH to the Glu/GABA balance perturbed in epilepsy.

Local ozone therapy options for lumbosacral dorsopathy.

The characteristic resistance of dorsopathies to conventional therapy explains the attention to new technologies that combine several therapeutic links and, in particular, ozone therapy. The study involved 90 patients under the age of 55 in the exacerbation phase of lumbar and sacrum dorsopathy with the leading vascular component. The patients were divided into three groups, in which basic medical and physical treatment was given. At the same time, ozone therapy was used the first two groups: the 1st group received standard ozone therapy, with a predominant selection of algic zones, the 2nd - according to the rules of biopuncture, affecting the complex of segmental, distant and "vascular" points. In the 3rd control group, the correction was limited to a standard therapeutic complex. The verification of the observed changes was carried out through clinical, psychological and electrophysiological analysis. As a result, both ozone therapy schemes (effective in 69% and 73% of observations respectively) were found to have a reliable advantage over the base complex, where 49% of patients demonstrated improvement. Differences within the ozone therapy groups themselves related to the achievement of a stable effect (in the 2nd group 2.6 days earlier) and the degree of reduction of vaso-reflex reactions (observed in 50% and 75% of observations respectively). Thus, by bringing in additional control methods, it has been proven that the implementation of ozone therapy in compliance with the rules of biopuncture ensures faster and more sustainable effects.

The Location of Disease-Causing DES Variants Determines the Severity of Phenotype and the Morphology of Sarcoplasmic Aggregates.

Desmin (DES) is the main intermediate muscle filament that connects myofibrils individually and with the nucleus, sarcolemma, and organelles. Pathogenic variants of DES cause desminopathy, a disorder affecting the heart and skeletal muscles. We aimed to analyze the clinical features, morphology, and distribution of desmin aggregates in skeletal muscle biopsies of patients with desminopathy and to correlate these findings with the type and location of disease-causing DES variants. This retrospective study included 30 patients from 20 families with molecularly confirmed desminopathy from 2 neuromuscular referral centers. We identified 2 distinct patterns of desmin aggregates: well-demarcated subsarcolemmal aggregates and diffuse aggregates with poorly delimited borders. Pathogenic variants located in the 1B segment and the tail domain of the desmin molecule are more likely to present with early-onset cardiomyopathy compared to patients with variants in other segments. All patients with mutations in the 1B segment had well-demarcated subsarcolemmal aggregates, but none of the patients with variants in other desmin segments showed such histological features. We suggest that variants located in the 1B segment lead to well-shaped subsarcolemmal desmin aggregation and cause disease with more frequent cardiac manifestations. These findings will facilitate early identification of patients with potentially severe cardiac syndromes.

Efficient Assay and Marker Significance of NAD+ in Human Blood.

Oxidized nicotinamide adenine dinucleotide (NAD+) is a biological molecule of systemic importance. Essential role of NAD+ in cellular metabolism relies on the substrate action in various redox reactions and cellular signaling. This work introduces an efficient enzymatic assay of NAD+ content in human blood using recombinant formate dehydrogenase (FDH, EC 1.2.1.2), and demonstrates its diagnostic potential, comparing NAD+ content in the whole blood of control subjects and patients with cardiac or neurological pathologies. In the control group (n = 22, 25-70 years old), our quantification of the blood concentration of NAD+ (18 µM, minimum 15, max 23) corresponds well to NAD+ quantifications reported in literature. In patients with demyelinating neurological diseases (n = 10, 18-55 years old), the NAD+ levels significantly (p < 0.0001) decrease (to 14 µM, min 13, max 16), compared to the control group. In cardiac patients with the heart failure of stage II and III according to the New York Heart Association (NYHA) functional classification (n = 24, 42-83 years old), the blood levels of NAD+ (13 µM, min 9, max 18) are lower than those in the control subjects (p < 0.0001) or neurological patients (p = 0.1). A better discrimination of the cardiac and neurological patients is achieved when the ratios of NAD+ to the blood creatinine levels, mean corpuscular volume or potassium ions are compared. The proposed NAD+ assay provides an easy and robust tool for clinical analyses of an important metabolic indicator in the human blood.

Delayed Impact of 2-Oxoadipate Dehydrogenase Inhibition on the Rat Brain Metabolism Is Linked to Protein Glutarylation.

Background: The DHTKD1-encoded 2-oxoadipate dehydrogenase (OADH) oxidizes 2-oxoadipate-a common intermediate of the lysine and tryptophan catabolism. The mostly low and cell-specific flux through these pathways, and similar activities of OADH and ubiquitously expressed 2-oxoglutarate dehydrogenase (OGDH), agree with often asymptomatic phenotypes of heterozygous mutations in the DHTKD1 gene. Nevertheless, OADH/DHTKD1 are linked to impaired insulin sensitivity, cardiovascular disease risks, and Charcot-Marie-Tooth neuropathy. We hypothesize that systemic significance of OADH relies on its generation of glutaryl residues for protein glutarylation. Using pharmacological inhibition of OADH and the animal model of spinal cord injury (SCI), we explore this hypothesis. Methods: The weight-drop model of SCI, a single intranasal administration of an OADH-directed inhibitor trimethyl adipoyl phosphonate (TMAP), and quantification of the associated metabolic changes in the rat brain employ established methods. Results: The TMAP-induced metabolic changes in the brain of the control, laminectomized (LE) and SCI rats are long-term and (patho)physiology-dependent. Increased glutarylation of the brain proteins, proportional to OADH expression in the control and LE rats, represents a long-term consequence of the OADH inhibition. The proportionality suggests autoglutarylation of OADH, supported by our mass-spectrometric identification of glutarylated K155 and K818 in recombinant human OADH. In SCI rats, TMAP increases glutarylation of the brain proteins more than OADH expression, inducing a strong perturbation in the brain glutathione metabolism. The redox metabolism is not perturbed by TMAP in LE animals, where the inhibition of OADH increases expression of deglutarylase sirtuin 5. The results reveal the glutarylation-imposed control of the brain glutathione metabolism. Glutarylation of the ODP2 subunit of pyruvate dehydrogenase complex at K451 is detected in the rat brain, linking the OADH function to the brain glucose oxidation essential for the redox state. Short-term inhibition of OADH by TMAP administration manifests in increased levels of tryptophan and decreased levels of sirtuins 5 and 3 in the brain. Conclusion: Pharmacological inhibition of OADH affects acylation system of the brain, causing long-term, (patho)physiology-dependent changes in the expression of OADH and sirtuin 5, protein glutarylation and glutathione metabolism. The identified glutarylation of ODP2 subunit of pyruvate dehydrogenase complex provides a molecular mechanism of the OADH association with diabetes.

Diversity of the virome associated with alfalfa (Medicago sativa L.) in the U.S. Pacific Northwest.

Alfalfa (Medicago sativa L.) is one of the most extensively cultivated forage legumes in the world. It is currently the third most valuable field crop in the United States with an estimated value of over $9.3 billion. Alfalfa productivity is limited by various infectious diseases that can reduce forage yield and quality and shorten stand life. The crop can frequently be infected with a diverse array of pathogens and other organisms that have distinct life cycles, biology, and mode of action. Among them are many coinfecting viruses, that greatly contribute to the heterogeneity of within-host pathogenic communities, representing a ubiquitous and abundant background for all other host-pathogen interactions. Regrettably, the impact of viral diseases, their role in alfalfa health and involvement in the severity of multi-pathogen infections are often underestimated and not well understood. As high-throughput sequencing approaches have been developed, opportunities to delve into these complex interactions can be realized. In this work, we have characterized a diversity of viral populations in several commercial alfalfa production fields located in the U.S. Pacific Northwest. At least 45 distinct viruses have been identified in all alfalfa samples. Among them some were known to infect the crop prior to this study, and others were designated as emerging, novel and viruses integrated into the alfalfa genome. Known viruses included alfalfa mosaic virus, pea streak virus and bean leafroll virus, while among emerging and novel agents were alfalfa virus S, cherry virus Trakiya, several rhabdoviruses and others. Additional biological and impact studies will be needed to determine if newly identified viruses, especially those that have not been reported from alfalfa before, should be considered pathogens of this crop.

Expanding the RNA virome of nematodes and other soil-inhabiting organisms.

In recent years, several newly discovered viruses infecting free-living nematodes, sedentary plant-parasitic nematodes, and migratory root lesion nematodes have been described. However, to the best of our knowledge, no comprehensive research focusing exclusively on metagenomic analysis of the soil nematode community virome has thus far been carried out. In this work, we have attempted to bridge this gap by investigating viral communities that are associated with soil-inhabiting organisms, particularly nematodes. This study demonstrates a remarkable diversity of RNA viruses in the natural soil environment. Over 150 viruses were identified in different soil-inhabiting hosts, of which more than 139 are potentially new virus species. Many of these viruses belong to the nematode virome, thereby enriching our understanding of the diversity and evolution of this complex part of the natural ecosystem.

Evaluation of Wheat Resistance to Snow Mold Caused by Microdochium nivale (Fr) Samuels and I.C. Hallett under Abiotic Stress Influence in the Central Non-Black Earth Region of Russia.

Microdochium nivale is one of the most harmful fungal diseases, causing colossal yield losses and deteriorating grain quality. Wheat genotypes from the world collection of the N.I. Vavilov Institute (VIR) were evaluated for fifty years to investigate their resistance to biotic stress factors (M. nivale). Between 350 to 1085 of winter wheat genotypes were investigated annually. Ten out of fifty years were identified as rot epiphytotics (1978, 1986, 1989, 1990, 1993, 1998, 2001, 2003, 2005 and 2021). The wheat collection was investigated by following the VIR methodological requirements and CMEA unified classification of Triticum aestivum L. The field investigations were carried out in the early spring during fixed-route observations and data collection was included on the spread and development degree of the disease, followed by microbiological and microscopic pathogen identifications. The observations revealed that the primary reason for pink snow mold to infect the wheat crops was abiotic stress factors, such as thawed soil covered in snow that increased the soil temperature by 1.0-4.6 °C above normal. Under these conditions, the plants kept growing, quickly exhausting their carbohydrate and protein resources, thus weakening their immune systems, which made them an easy target for different infections, mainly cryophilic fungi, predominantly Microdochium nivale in the Moscow region. In some years, the joint effect of abiotic and biotic stresses caused crop failure, warranting the replanting of the spring wheat. The investigated wheat genotypes exhibited variable resistance to pink snow mold. The genotypes Mironovskaya 808 (k-43920) from Ukraine;l Nemchinovskaya 846 (k-56861), from Russia; Novobanatka (k-51761) from Yugoslavia; Liwilla (k-57580) from Poland; Zdar (UH 7050) from the Czech Republic; Maris Plowman (k-57944) from the United Kingdom; Pokal (k-56827) from Austria; Hvede Sarah (k-56289) from Denmark; Moldova 83 (k-59750) from Romania; Compal (k-57585) from Germany; Linna (k-45889) from Finland and Kehra (k-34228) from Estonia determined the sources, stability and tolerance to be used in advanced breeding programs.

Targeted transcriptomics reveals signatures of large-scale independent origins and concerted regulation of effector genes in Radopholus similis.

The burrowing nematode, Radopholus similis, is an economically important plant-parasitic nematode that inflicts damage and yield loss to a wide range of crops. This migratory endoparasite is widely distributed in warmer regions and causes extensive destruction to the root systems of important food crops (e.g., citrus, banana). Despite the economic importance of this nematode, little is known about the repertoire of effectors owned by this species. Here we combined spatially and temporally resolved next-generation sequencing datasets of R. similis to select a list of candidates for the identification of effector genes for this species. We confirmed spatial expression of transcripts of 30 new candidate effectors within the esophageal glands of R. similis by in situ hybridization, revealing a large number of pioneer genes specific to this nematode. We identify a gland promoter motif specifically associated with the subventral glands (named Rs-SUG box), a putative hallmark of spatial and concerted regulation of these effectors. Nematode transcriptome analyses confirmed the expression of these effectors during the interaction with the host, with a large number of pioneer genes being especially abundant. Our data revealed that R. similis holds a diverse and emergent repertoire of effectors, which has been shaped by various evolutionary events, including neofunctionalization, horizontal gene transfer, and possibly by de novo gene birth. In addition, we also report the first GH62 gene so far discovered for any metazoan and putatively acquired by lateral gene transfer from a bacterial donor. Considering the economic damage caused by R. similis, this information provides valuable data to elucidate the mode of parasitism of this nematode.

Genome-wide identification of endogenous viral sequences in alfalfa (Medicago sativa L.).

Endogenous viral elements (EVEs) have been for the most part described in animals and to a less extent in plants. The endogenization was proposed to contribute toward evolution of living organisms via horizontal gene transfer of novel genetic material and resultant genetic diversity. During the last two decades, several full-length and fragmented EVEs of pararetroviral and non-retroviral nature have been identified in different plant genomes, both monocots and eudicots. Prior to this work, no EVEs have been reported in alfalfa (Medicago sativa L.), the most cultivated forage legume in the world. In this study, taking advantage of the most recent developments in the field of alfalfa research, we have assessed alfalfa genome on the presence of viral-related sequences. Our analysis revealed segmented EVEs resembling two dsDNA reverse-transcribing virus species: Soybean chlorotic mottle virus (family Caulimoviridae, genus Soymovirus) and Figwort mosaic virus (family Caulimoviridae, genus Caulimovirus). The EVEs appear to be stable constituents of the host genome and in that capacity could potentially acquire functional roles in alfalfa's development and response to environmental stresses.

Dusty Plasma in Inhomogeneous Magnetic Fields in a Stratified Glow Discharge.

We study the dynamics of dust particles in a stratified glow discharge in inhomogeneous magnetic fields. Dust structures are formed in standing striations, in which traps for dust particles arise. When a magnetic field is applied, these structures begin to rotate. The observations were carried out in striations near the end of the solenoid, where the region of an inhomogeneous magnetic field begins. With an increase in the magnetic field, the dusty structure can be deformed. The rotation of a dusty structure in an inhomogeneous magnetic field has been studied in detail; it has its own peculiarities in comparison with rotation in a uniform field. We have considered the mechanisms of such rotation and estimated its velocity.