Plant Virus Diseases Research Articles

Exogenous delivery of dsRNA for management of mungbean yellow mosaic virus on blackgram.

Exogenous application of dsRNA molecules targeting MYMV genes offers a promising approach to effectively mitigate yellow mosaic disease in blackgram, demonstrating potential for sustainable plant viral disease management. The exogenous application of double-stranded RNA (dsRNA) molecules to control plant viral diseases is gaining traction due to its advantages over conventional methods, such as target specificity, non-polluting nature, and absence of residue formation. Furthermore, this approach does not involve genome modification. In this study, dsRNA molecules targeting the coat protein gene (dsCP) and replication initiator protein gene (dsRep) of mungbean yellow mosaic virus (MYMV) were synthesised using an in vitro transcription method. To evaluate the effectiveness of dsRNA treatment, blackgram plants exhibiting MYMV symptoms at the first trifoliate stage were subjected to exogenous application of dsRNA. Second, third, and fourth trifoliate leaves, which emerged at 7, 15, and 21days after dsRNA application, respectively, were monitored for MYMV symptoms. Remarkably, a significant reduction in yellow mosaic disease (YMD) symptoms was observed in the newly emerged trifoliate leaves of MYMV-infected blackgram plants after treatment with dsRNA targeting both gene regions. This reduction was evident as a decrease in the intensity of yellow mosaic coverage on the leaf lamina compared to control. dsCP effectively reduced the MYMV titre in the treated plants for up to 15days. However, dsRep demonstrated greater efficiency in conferring resistance to MYMV at 15days post-application. These findings were supported by quantitative real-time PCR analysis, where the observed Ct values for DNA extracted from dsRep-treated plants were significantly higher compared to the Ct values of DNA from dsCP-treated plants at 15days post-application. Similarly, higher viral copy numbers were observed in dsCP-treated plants 15days after dsRNA treatment, in contrast to plants treated with dsRep.

Research Progress of Piriformospora indica in Improving Plant Growth and Stress Resistance to Plant.

Piriformospora indica (Serendipita indica), a mycorrhizal fungus, has garnered significant attention in recent decades owing to its distinctive capacity to stimulate plant growth and augment plant resilience against environmental stressors. As an axenically cultivable fungus, P. indica exhibits a remarkable ability to colonize varieties of plants and promote symbiotic processes by directly influencing nutrient acquisition and hormone metabolism. The interaction of plant and P. indica raises hormone production including ethylene (ET), jasmonic acid (JA), gibberellin (GA), salicylic acid (SA), and abscisic acid (ABA), which also promotes root proliferation, facilitating improved nutrient acquisition, and subsequently leading to enhanced plant growth and productivity. Additionally, the plant defense system was employed by P. indica colonization and the defense genes associated with oxidation resistance were activated subsequently. This fungus-mediated defense response elicits an elevation in the enzyme activity of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and, finally, bolsters plant tolerance. Furthermore, P. indica colonization can initiate local and systemic immune responses against fungal and viral plant diseases through signal transduction mechanisms and RNA interference by regulating defense gene expression and sRNA secretion. Consequently, P. indica can serve diverse roles such as plant promoter, biofertilizer, bioprotectant, bioregulator, and bioactivator. A comprehensive review of recent literature will facilitate the elucidation of the mechanistic foundations underlying P. indica-crop interactions. Such discussions will significantly contribute to an in-depth comprehension of the interaction mechanisms, potential applications, and the consequential effects of P. indica on crop protection, enhancement, and sustainable agricultural practices.

Plant Virus Sensor for the Rapid Detection of Bean Pod Mottle Virus Using Virus-Specific Nanocavities.

This study presents a miniaturized sensor for rapid, selective, and sensitive detection of bean pod mottle virus (BPMV) in soybean plants. The sensor employs molecularly imprinted polymer technology to generate BPMV-specific nanocavities in porous polypyrrole. Leveraging the porous structure, high surface reactivity, and electron transfer properties of polypyrrole, the sensor achieves a sensitivity of 143 μA ng-1 mL cm-2, a concentration range of 0.01-100,000 ng/mL, a detection time of less than 2 min, and a detection limit of 41 pg/mL. These capabilities outperform those of conventional methods, such as enzyme-linked immunosorbent assays and reverse transcription polymerase chain reactions. The sensor possesses the ability to distinguish BPMV-infected soybean plants from noninfected ones while rapidly quantifying virus levels. Moreover, it can reveal the spatial distribution of virus concentration across distinct leaves, a capability not previously attained by cost-effective sensors for such detailed viral data within a plant. The BPMV-specific nanocavities can also be easily restored and reactivated for multiple uses through a simple wash with acetic acid. While MIP-based sensors for plant virus detection have been relatively understudied, our findings demonstrate their potential as portable, on-site diagnostic tools that avoid complex and time-consuming sample preparation procedures. This advancement addresses a critical need in plant virology, enhancing the detection and management of plant viral diseases.

Construction of a Delivery Platform for Vaccine Based on Modified Nanotubes: Sustainable Prevention against Plant Viral Disease, Simplified Preparation Method, and Protection of Plasmid.

Control of plant viral diseases through cross-protection conferred by an attenuated vaccine is an important strategy for plant protection. However, the mutated site of an attenuated vaccine may not be stably inherited, while viruses have evolved efficient repair mechanisms for the maintenance of genomic integrity. Here, the wide host range and broad selection of mutation sites in cucumber mosaic virus (CMV) enabled construction of an attenuated vaccine through insertional mutation of the CMV 2b protein. CMV-R2E was stably inherited in tobacco for more than 10 generations and had a high relative control efficacy of CMV. Then, the use of polyetherimide (PEI)-modified functionalized carboxylated single-walled carbon nanotubes (PSWNTs) was investigated for vaccine delivery to address the problems of poor stability, complex procedure on field application, and exacting storage conditions with Agrobacterium inoculation. After co-incubating at a 1:300 ratio for 30 min, the vaccine and PSWNTs combined to form pCMV-R2E@PSWNTs, which resulted in a significant increase in the average height of the nanoparticles from 6.56 to 72.34 nm. The relative control efficacy of pCMV-R2E@PSWNTs to CMV was found to be 90.37%. Furthermore, the protective effect of PSWNTs on plasmids was investigated under various environmental conditions and the potential plant toxicity of pCMV-R2E@PSWNTs was assessed, providing a theoretical basis for field application of the vaccine nano-delivery system. A highly effective, stable viral vaccine for plants was thus developed and combined with nanocarriers to address the problems of field application. This approach has the potential to enable wider use of attenuated vaccines for sustainable prevention against plant viral disease in the field.

Integrated Approaches for Management of Whitefly (Bemisia tabaci Gennadius) to Prevent Chilli Leaf Curl Disease in Chilli Crop: A Review

Whitefly (Bemisia tabaci Gennadius) poses significant agricultural challenges due to its role as a vector for plant viral diseases, particularly the Chilli leaf curl disease (ChiLCD). This review discusses the multifaceted management strategies and elaborates on the future prospects and research directions to combat these threats. Precision agriculture is identified as a pivotal tool, with the utilization of drones, machine learning, and automated pesticide application offering early pest detection and targeted interventions. Exploration of novel biological controls, including RNA interference and microbiome manipulation, provide innovative avenues for sustainable pest management. A notable concern remains the development of resistance in pests. Genomic studies and an in-depth understanding of biochemical pathways have shed light on potential strategies to address resistance build-up mechanisms. Behavioral studies elucidate the adaptive changes in pests in response to pesticides. Effective management is not solely reliant on technological and biological advancements. Strengthening the linkages between farmers, extension services, and researchers is essential for the dissemination and practical application of research findings. Digital platforms, participatory research, and feedback mechanisms have emerged as beneficial in this context. While significant challenges persist in the management of Bemisia tabaci and ChiLCD, integrated approaches that combine advanced technology, innovative research, and robust stakeholder partnerships offer a promising pathway forward. This synthesis underscores the importance of interdisciplinary collaborations and continuous research in shaping sustainable agricultural practices.

New technologies provide innovative opportunities to enhance understanding of major virus diseases threatening global food security.

Plant viruses pose a continuous and serious threat to crop production worldwide, while globalization and climate change are exacerbating the establishment and rapid spread of new viruses. Simultaneously, developments in genome sequencing technology, nucleic acid amplification methods, and epidemiological modeling are providing plant health specialists with unprecedented opportunities to confront these major threats to the food security and livelihoods of millions of resource-constrained smallholders. In this perspective, we have used recent examples of integrated application of these technologies to enhance understanding of the emergence of plant viral diseases of key food security crops in low- and middle-income countries. We highlight how international funding and collaboration have enabled high-throughput sequencing-based surveillance approaches, targeted field and lab-based diagnostic tools, and modeling approaches that can be effectively used to support surveillance and preparedness against existing and emerging plant viral threats. The importance of national and international collaboration and the future role of CGIAR in further supporting these efforts, including building capabilities to make optimal use of these technologies in low- and middle-income countries is discussed.

Fluorescent dual-mode assay of plant viral disease with polymerase chain reaction amplification

Plant viral diseases pose serious risk to the quality and yield of different crops. Herein, we described a highly sensitive and accurate immunosensor for early diagnosis of plant viral disease by using dual-signal readout with polymerase chain reaction (PCR) amplification. The sensor utilizes 6-carboxyfluorescein group (FAM) and tetramethyl-6-carboxyrhodamine (TAMRA) labeled primers as signal probes and their fluorescence signals were effectively quenched by graphene oxide (GO). In the presence of target plant viral related nucleic acid, the cDNA template could initiate the formation of long duplex PCR products with multiple signal probes. Such duplex PCR products cannot be quenched with GO, resulting in an obvious fluorescence signal. The results showed that FAM and TAMRA signals were proportional to the logarithm of the target cDNA concentration in the range of 10 fM–100 pM. The detection limit for the target cDNA was 0.08 fM for FAM and 0.07 fM for TAMRA, respectively. The practical application of our proposed strategy was successfully demonstrated by detection of emerging tobacco mosaic virus (TMV) infections in tobacco samples collected in the field, illuminating the possibility of applying this sensing platform for early diagnosis of plant disease.

A chitosan-coated lentinan-loaded calcium alginate hydrogel induces broad-spectrum resistance to plant viruses by activating Nicotiana benthamiana calmodulin-like (CML) protein 3.

Control of plant virus diseases largely depends on the induced plant defence achieved by the external application of synthetic chemical inducers with the ability to modify defence-signalling pathways. However, most of the molecular mechanisms underlying these chemical inducers remain unknown. Here, we developed a chitosan-coated lentinan-loaded hydrogel and discovered how it protects plants from different virus infections. The hydrogel was synthesized by coating chitosan on the surface of the calcium alginate-lentinan (LNT) hydrogel (SL-gel) to form a CSL-gel. CSL-gels exhibit the capacity to prolong the stable release of lentinan and promote Ca2+ release. Application of CSL-gels on the root of plants induces broad-spectrum resistance against plant viruses (TMV, TRV, PVX and TuMV). RNA-seq analysis identified that Nicotiana benthamiana calmodulin-like protein gene 3 (NbCML3) is upregulated by the sustained release of Ca2+ from the CSL-gel, and silencing and overexpression of NbCML alter the susceptibility and resistance of tobacco to TMV. Our findings provide evidence that this novel and synthetic CSL-gel strongly inhibits the infection of plant viruses by the sustainable release of LNT and Ca2+ . This study uncovers a novel mode of action by which CSL-gels trigger NbCML3 expression through the stable and sustained release of Ca2+ .

Effects of holy basil (Ocimum sanctum) on viral disease of chili (Capsicum annum L.) under mixed crop cultivation

Chili is one of the important commodities in Indonesia. Chili cultivation faces many obstacles, leading to a decrease in production, such as virus infections. Yellow leaf curl and curly top viruses are groups of viruses that are often found in chili fields. This research was conducted to investigate the effect of intercropping (basil-chili) in suppressing viral diseases, especially yellow leaf curl and curly top viruses. A Randomized block design was used for this research, including intercropping and monoculture. The parameters observed in this study included disease incidence and intensity, the number and weight of chilies. Symptoms of virus infection include leaf curl, yellowing, and stunting. The disease has been reported to be transmitted by insect vectors, such as Aphis gossypii and Bemisia tabaci. The results showed that the incidence and intensity of yellow leaf curl and curly top virus diseases in chili pepper and basil plants were not significantly different in each treatment. The number of healthy chilies and their weight were also not significantly different. Damaged chilies are fruits that have been attacked by fruit flies. Basil intercropped with chilies attracts fruit flies, which affects the quantity and weight of the harvested chilies. The population of B. tabaci was significantly different in each treatment, while A. gossypii did not show significant differences among the treatments. Intercropping basil and chili increased the population of A. gossypii, while the population of B. tabaci decreased in this treatment. These two insect pests are vectors for yellow leaf curl and curly top viruses.

Comparative evolutionary analyses of eight whitefly Bemisia tabaci sensu lato genomes: cryptic species, agricultural pests and plant-virus vectors

BackgroundThe group of > 40 cryptic whitefly species called Bemisia tabaci sensu lato are amongst the world’s worst agricultural pests and plant-virus vectors. Outbreaks of B. tabaci s.l. and the associated plant-virus diseases continue to contribute to global food insecurity and social instability, particularly in sub-Saharan Africa and Asia. Published B. tabaci s.l. genomes have limited use for studying African cassava B. tabaci SSA1 species, due to the high genetic divergences between them. Genomic annotations presented here were performed using the ‘Ensembl gene annotation system’, to ensure that comparative analyses and conclusions reflect biological differences, as opposed to arising from different methodologies underpinning transcript model identification.ResultsWe present here six new B. tabaci s.l. genomes from Africa and Asia, and two re-annotated previously published genomes, to provide evolutionary insights into these globally distributed pests. Genome sizes ranged between 616—658 Mb and exhibited some of the highest coverage of transposable elements reported within Arthropoda. Many fewer total protein coding genes (PCG) were recovered compared to the previously published B. tabaci s.l. genomes and structural annotations generated via the uniform methodology strongly supported a repertoire of between 12.8—13.2 × 103 PCG. An integrative systematics approach incorporating phylogenomic analysis of nuclear and mitochondrial markers supported a monophyletic Aleyrodidae and the basal positioning of B. tabaci Uganda-1 to the sub-Saharan group of species. Reciprocal cross-mating data and the co-cladogenesis pattern of the primary obligate endosymbiont ‘Candidatus Portiera aleyrodidarum’ from 11 Bemisia genomes further supported the phylogenetic reconstruction to show that African cassava B. tabaci populations consist of just three biological species. We include comparative analyses of gene families related to detoxification, sugar metabolism, vector competency and evaluate the presence and function of horizontally transferred genes, essential for understanding the evolution and unique biology of constituent B. tabaci. s.l species.ConclusionsThese genomic resources have provided new and critical insights into the genetics underlying B. tabaci s.l. biology. They also provide a rich foundation for post-genomic research, including the selection of candidate gene-targets for innovative whitefly and virus-control strategies.

Evaluation of Tomato (<i>Lycopersicon lycopersicum</i> (L.) Genotypes for their Reaction to <i>Tomato mosaic virus</i> (ToMV) Infection in Kebbi State, Nigeria

Tomato mosaic virus (ToMV) is among the most devastating viral diseases of tomato worldwide and it can cause yield losses of up to 40%. One of the effective managements of plant viral diseases is the use of resistant genotypes. This research was conducted to determine the reaction of tomato genotypes to Tomato mosaic virus (ToMV) infection. The experiment consists of five tomato genotypes which were evaluated for resistance to ToMV infection under screen-house conditions using Completely Randomized Design (CRD) with three replicates. The treatments were Dantaya, Danwarai, Dan-Niko, Dan-Heka, and Hybrid Platinum, which are the five most preferred farmers varieties in Kebbi State. Prior to mechanical inoculation, ToMV-infected leaf samples used as source of inoculum were tested ToMV positive using Direct Antibody Coating-Enzyme Linked Immunoassay (DAC-ELISA). Thirty-six (36) seedlings of each genotype were transplanted into plastic pots containing compost and seedlings recovery were recorded two weeks after transplanting (WAT) before inoculation. Hybrid Platinum has low establishment percentage (72.22%), compared to DanHeka and Dan-Niko with both 100%. All the genotypes evaluated were infected when inoculated with ToMV but with significant variation (P = 0.05) in their reaction to ToMV infection. Dantaya recorded the highest percent disease incidence of 50.00% while, Platinum recorded the lowest percent disease incidence of 31.94%. Three genotypes were susceptible to ToMV while, two were resistant to ToMV. The high incidence of ToMV found on farmers preferred tomato genotypes in Kebbi State is of great management concern. Also, this has implication for tomato productivity and yield in the state.

Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) popülasyonlarında neonikotinoid ve sentetik piretroid insektisitlerin tekli ve karışımlarına karşı direnç durumu

The peach potato aphid, Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae), a vector of many plant virus diseases, causes damage to its wide range of hosts by direct feeding. Chemical control has been the primary method to control this species, and the intensive use of insecticides has led to the development of resistance. In this study, conducted between the years 2017-2019, firstly resistance ratio of five M. persicae populations from Antalya, Türkiye were determined by leaf-dip bioassay method. The field populations showed significant resistance to thiamethoxam (between 201-332 fold) and lambda-cyhalothrin (between 50-103 fold) when compared to susceptible population. To identify whether resistance mediated by mutations in sodium channel and nicotinic acetylcholine receptor, DNA regions that encompass “mutation hot-spot” were sequenced. This revealed no population contained R81T mutation that has been previously linked with neonicotinoid resistance. As to synthetic pyrethroid resistance, the L1014F kdr mutation was fixed in all field populations. This study is the first description of kdr mutation in M. persicae populations from Türkiye. Bioassay results also indicated that the toxicity of thiamethoxam and lambda-cyhalothrin mixture was higher than that of lambda-cyhalothrin alone. Our findings can make significant contributions to M. persicae resistance management.

Discovery of Chiral Diamine Derivatives Containing 1,2-Diphenylethylenediamine as Novel Antiviral and Fungicidal Agents.

Severe plant virus diseases lead to poor harvests and poor crop quality, and the lack of effective suppressive drugs makes plant disease control a huge challenge. Natural product-based structural simplification is an important strategy for finding novel pesticide candidates. According to our previous research on the antiviral activities of harmine and tetrahydroharmine derivatives, a series of chiral diamine compounds were designed and synthesized by means of structural simplification using diamines in natural products as the core structure in this work, and the antiviral and fungicidal activities were investigated. Most of these compounds displayed higher antiviral activities than those of ribavirin. Compounds 1a and 4g displayed higher antiviral activities than ningnanmycin at 500 μg/mL. The antiviral mechanism research revealed that compounds 1a and 4g could inhibit virus assembly by binding to tobacco mosaic virus (TMV) CP and interfere with the assembly process of TMV CP and RNA via transmission electron microscopy and molecular docking. Further fungicidal activity tests showed that these compounds displayed broad-spectrum fungicidal activities. Compounds 3a, 3i, 5c, and 5d with excellent fungicidal activities against Fusarium oxysporum f.sp. cucumerinum can be considered as new fungicidal candidates for further research. The current work provides a reference to the development of agricultural active ingredients in crop protection.

Discovery of novel phenothiazine derivatives as new agrochemical alternatives for treating plant viral diseases.

Plant viral diseases, namely 'plant cancer', are extremely difficult to control. Even worse, few antiviral agents can effectively control and totally block viral infection. There is an urgent need to explore and discover novel agrochemicals with high activity and a unique mode of action to manage these refractory diseases. Forty-one new phenothiazine derivatives were prepared and their inhibitory activity against tobacco mosaic virus (TMV) was assessed. Compound A8 had the highest protective activity against TMV, with a half-maximal effective concentration (EC50 ) of 115.67 μg/mL, which was significantly better than that of the positive controls ningnanmycin (271.28 μg/mL) and ribavirin (557.47 μg/mL). Biochemical assays demonstrated that compound A8 could inhibit TMV replication by disrupting TMV self-assembly, but also enabled the tobacco plant to enhance its defense potency by increasing the activities of various defense enzymes. In this study, novel phenothiazine derivatives were elaborately fabricated and showed remarkable anti-TMV behavior that possessed the dual-action mechanisms of inhibiting TMV assembly and invoking the defense responses of tobacco plants. Moreover, new agrochemical alternatives based on phenothiazine were assessed for their antiviral activities and showed extended agricultural application. © 2023 Society of Chemical Industry.

Plant Viruses and Viral Host Plants Newly Reported in South Korea in 2020–2022

With the development of advanced virus diagnostic technologies, numerous viruses, including novel viruses, have been identified explosively from various biological samples around the world over the last decade. For plant viruses, approximately 376 novel viruses have been reported in the last three years. Information on the occurrence and host ranges of plant viral diseases in a particular country or region is very important for diagnosis, quarantine, and control of the viral diseases. Recently, based on active research on the diagnosis and identification of plant viruses, a significant number of newly occurring viruses and new viral host plants have been reported in South Korea. This review paper provides integrated information on plant viruses and viral host plants newly reported in South Korea between 2020 and 2022 to help diagnose, control, and quarantine plant virus diseases in crop fields.

Discovery of phosphonate derivatives containing different substituted 1,2,3-triazole motif as promising tobacco mosaic virus (TMV) helicase inhibitors for controlling plant viral diseases.

The discovery and identification of targets is of far-reaching significance for developing novel pesticide candidates and increasing the probability of success. To explore and identify highly effective tobacco mosaic virus (TMV) helicase-targeted lead structures, a series of novel phosphonate derivatives containing a 1,2,3-triazole motif were rationally engineered and their antiviral activity was assessed. Bioassay results showed that the optimized B17 exhibited more potent curative activity (EC50 = 271.5 μg mL-1 ) against TMV in vivo, which was superior to that of commercial Ribavirin (EC50 = 689.3 μg mL-1 ). B17 presented a stronger binding capacity through binding analysis with helicase, affording a corresponding value of 12.7 μM. Enzyme activity assay showed B17 exhibited excellent inhibitory activity on TMV helicase (39.2% at 300 μM). Furthermore, molecular docking simulations demonstrated that B17 displayed strong hydrogen-bond interactions (2.1, 2.1, 2.2, and 3.2 Å) with Ala-33, Gly-10, Gly-8, and Glu-217 of TMV helicase. Encouragingly, transmission electron microscopy analysis revealed that B17 could remarkably disrupt surface morphology and inhibit TMV proliferation. Additionally, these compounds also displayed potential anti-CMV (cucumber mosaic virus) and antipathogens (Xanthomonas oryzae pv. oryzae and Xanthomonas axonopodis pv. citri) by expanding their applications in agriculture. Current research demonstrated that B17 could be considered as a potential antiviral agent alternative though targeting TMV helicase. © 2023 Society of Chemical Industry.

High throughput sequencing technologies complemented by growers’ perceptions highlight the impact of tomato virome in diversified vegetable farms and a lack of awareness of emerging virus threats

The number of small-scale diversified vegetable growers in industrialized countries has risen sharply over the last 10 years. The risks associated with plant viruses in these systems have been barely studied in Europe, yet dramatic virus emergence events, such as tomato brown fruit rugose virus (ToBRFV), sometimes occur. We developed a methodology that aimed to understand better the implications related to viruses for tomato production in Belgian’s vegetable farms by comparing growers’ perception and the presence of plant-viral-like symptoms (visual inspection) with non-targeting detection of nearly all viruses present in the plants by high throughput sequencing technologies (HTS). Virus presence and impact were interpreted considering the farm’s typology and cultural practices, and the grower’s professional profiles. Overall, the data indicated that most growers have limited understanding of tomato viruses and are not concerned about them. Field observations were correlated to this perception as the prevalence of symptomatic plants was usually lower than 1%. However, important and potentially emergent viruses, mainly transmitted by insects, were detected in several farms. Notably, the presence of these viruses tended to be associated with the number of plant species grown per site (diversity) but not with a higher awareness of the growers regarding plant viral diseases, or a higher number of symptomatic plants. In addition, both HTS and perception analysis underlined the rising incidence and importance of an emergent virus: Physostegia chlorotic mottle virus. This study also revealed a notable lack of knowledge among producers regarding the highly contagious quarantine virus ToBRFV. Overall, the original methodology developed here, involving the integration of two separate fields of study (social science with phytopathology using HTS technologies), could be applied to other crops in other systems to identify emergent risks associated with plant viruses, and can highlight the communication needed with growers to mitigate epidemics. This exploratory investigation provides relevant insights, which, ideally, would be further tested on wider samples to allow finer statistical treatment to be performed.

Integrated transcriptome and microRNA sequencing analyses reveal gene responses in poplar leaves infected by the novel pathogen bean common mosaic virus (BCMV).

Recently, a novel poplar mosaic disease caused by bean common mosaic virus (BCMV) was investigated in Populus alba var. pyramidalis in China. Symptom characteristics, physiological performance of the host, histopathology, genome sequences and vectors, and gene regulation at the transcriptional and posttranscriptional levels were analyzed and RT-qPCR (quantitative reverse transcription PCR) validation of expression was performed in our experiments. In this work, the mechanisms by which the BCMV pathogen impacts physiological performance and the molecular mechanisms of the poplar response to viral infection were reported. The results showed that BCMV infection decreased the chlorophyll content, inhibited the net photosynthesis rate (Pn) and stomatal conductance (Gs), and significantly changed chlorophyll fluorescence parameters in diseased leaves. Transcriptome analysis revealed that the expression of the majority of DEGs (differentially expressed genes) involved in the flavonoid biosynthesis pathway was promoted, but the expression of all or almost all DEGs associated with photosynthesis-antenna proteins and the photosynthesis pathway was inhibited in poplar leaves, suggesting that BCMV infection increased the accumulation of flavonoids but decreased photosynthesis in hosts. Gene set enrichment analysis (GSEA) illustrated that viral infection promoted the expression of genes involved in the defense response or plant-pathogen interaction. MicroRNA-seq analysis illustrated that 10 miRNA families were upregulated while 6 families were downregulated in diseased poplar leaves; moreover, miR156, the largest family with the most miRNA members and target genes, was only differentially upregulated in long-period disease (LD) poplar leaves. Integrated transcriptome and miRNA-seq analyses revealed 29 and 145 candidate miRNA-target gene pairs; however, only 17 and 76 pairs, accounting for 2.2% and 3.2% of all DEGs, were authentically negatively regulated in short-period disease (SD) and LD leaves, respectively. Interestingly, 4 miR156/SPL (squamosa promoter-binding-like protein) miRNA-target gene pairs were identified in LD leaves: the miR156 molecules were upregulated, but SPL genes were downregulated. In conclusion, BCMV infection significantly changed transcriptional and posttranscriptional gene expression in poplar leaves, inhibited photosynthesis, increased the accumulation of flavonoids, induced systematic mosaic symptoms, and decreased physiological performance in diseased poplar leaves. This study elucidated the fine-tuned regulation of poplar gene expression by BCMV; moreover, the results also suggested that miR156/SPL modules played important roles in the virus response and development of viral systematic symptoms in plant virus disease.

Species of the Euscelis Brullé Genus Damaged to Medicago in the Fergana Valley

The article presents materials on the study of herbivorous pests of Medicago in Fergana Valley from the order Homoptera, their species composition, the most harmful species of the EuscelisBrullé genus, their food relations, biological characteristics, harmfulness, features of development phases, their natural enemies were noted. It has been determined that the Cicadellidae family occupies a special place among the Homoptera; it is ecologically associated with various biotopes and plays an important role in agrobiocenosis. As a result of the research, it was revealed that the species of Homoptera, in particular cicadas, are characterized by complex bioecological features, highly specialized and well adapted for living in Fergana Valley. The studies are of practical importance, since some species of cicadas: Euscelis lineolata Brullé, Euscelis plebeius (Fallén)are pests of Medicago. The author revealed the harmfulness of cicada species found on Medicago, which is as follows: Insects suck juices from the vascular bundles of roots, stems, leaf veins and from leaf cells. They inflict wounds on the vegetative parts of the plant with their ovipositor during oviposition. Some species transmit viral plant diseases.

Plant virus resistance biotechnological approaches: From genes to the CRISPR/Cas gene editing system

Plant viruses cause crop losses in agronomically and economically important crops, making global food security a challenge. Although traditional plant breeding has been effective in controlling plant viral diseases, it is unlikely to solve the problems associated with the frequent emergence of new and more virulent virus species or strains. As a result, there is an urgent need to develop alternative virus control strategies that can be used to more easily contain viral diseases. A better understanding of plant defence mechanisms will open up new avenues for research into plant- pathogen interactions and the development of broad-spectrum virus resistance. The scientific literature was evaluated and structured in this review, and the results of the reliability of the methods of analysis used were filtered. As a result, we described the molecular mechanisms by which viruses interact with host plant cells. To develop an effective strategy for the control of plant pathogens with a significant intensity on the agricultural market, clear and standardised recommendations are required. The current review will provide key insights into the molecular underpinnings underlying the coordination of plant disease resistance, such as main classes of resistance genes, RNA interference, and the RNA-mediated adaptive immune system of bacteria and archaea – clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated Cas proteins – CRISPR/Cas. Future issues related to resistance to plant viral diseases will largely depend on integrated research to transfer fundamental knowledge to applied problems, bridging the gap between laboratory and field work.