RESUMEN
Many virus genomes encode proteases that facilitate infection. The molecular mechanism of plant recognition of viral proteases is largely unexplored. Using the system of Vigna unguiculata and cowpea mosaic virus (CPMV), we identified a cowpea lipid transfer protein (LTP1) which interacts with CPMV-encoded 24KPro, a cysteine protease, but not with the enzymatically inactive mutant 24KPro(C166A). Biochemical assays showed that LTP1 inhibited 24KPro proteolytic cleavage of the coat protein precursor large coat protein-small coat protein. Transient overexpression of LTP1 in cowpea reduced CPMV infection, whereas RNA interference-mediated LTP1 silencing increased CPMV accumulation in cowpea. LTP1 is mainly localized in the apoplast of uninfected plant cells, and after CPMV infection, most of the LTP1 is relocated to intracellular compartments, including chloroplast. Moreover, in stable LTP1-transgenic Nicotiana benthamiana plants, LTP1 repressed soybean mosaic virus (SMV) nuclear inclusion a protease activity, and accumulation of SMV was significantly reduced. We propose that cowpea LTP1 suppresses CPMV and SMV accumulation by directly inhibiting viral cysteine protease activity.
Asunto(s)
Proteínas Portadoras , Comovirus , Nicotiana , Enfermedades de las Plantas , Proteínas de Plantas , Vigna , Comovirus/metabolismo , Comovirus/fisiología , Comovirus/genética , Vigna/virología , Vigna/metabolismo , Nicotiana/virología , Nicotiana/metabolismo , Nicotiana/genética , Proteínas Portadoras/metabolismo , Proteínas Portadoras/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Enfermedades de las Plantas/virología , Proteasas de Cisteína/metabolismo , Proteasas de Cisteína/genética , Plantas Modificadas Genéticamente , Proteínas Virales/metabolismo , Proteínas Virales/genética , Proteínas de la Cápside/metabolismo , Proteínas de la Cápside/genética , Potyvirus/fisiología , Potyvirus/metabolismo , EndopeptidasasRESUMEN
KEY MESSAGE: Unraveling genetic markers for MYMIV resistance in urdbean, with 8 high-confidence marker-trait associations identified across diverse environments, provides crucial insights for combating MYMIV disease, informing future breeding strategies. Globally, yellow mosaic disease (YMD) causes significant yield losses, reaching up to 100% in favorable environments within major urdbean cultivating regions. The introgression of genomic regions conferring resistance into urdbean cultivars is crucial for combating YMD, including resistance against mungbean yellow mosaic India virus (MYMIV). To uncover the genetic basis of MYMIV resistance, we conducted a genome-wide association study (GWAS) using three multi-locus models in 100 diverse urdbean genotypes cultivated across six individual and two combined environments. Leveraging 4538 high-quality single nucleotide polymorphism (SNP) markers, we identified 28 unique significant marker-trait associations (MTAs) for MYMIV resistance, with 8 MTAs considered of high confidence due to detection across multiple GWAS models and/or environments. Notably, 4 out of 28 MTAs were found in proximity to previously reported genomic regions associated with MYMIV resistance in urdbean and mungbean, strengthening our findings and indicating consistent genomic regions for MYMIV resistance. Among the eight highly significant MTAs, one localized on chromosome 6 adjacent to previously identified quantitative trait loci for MYMIV resistance, while the remaining seven were novel. These MTAs contain several genes implicated in disease resistance, including four common ones consistently found across all eight MTAs: receptor-like serine-threonine kinases, E3 ubiquitin-protein ligase, pentatricopeptide repeat, and ankyrin repeats. Previous studies have linked these genes to defense against viral infections across different crops, suggesting their potential for further basic research involving cloning and utilization in breeding programs. This study represents the first GWAS investigation aimed at identifying resistance against MYMIV in urdbean germplasm.
Asunto(s)
Begomovirus , Resistencia a la Enfermedad , Estudio de Asociación del Genoma Completo , Enfermedades de las Plantas , Polimorfismo de Nucleótido Simple , Vigna , Vigna/genética , Vigna/virología , Resistencia a la Enfermedad/genética , Begomovirus/fisiología , Begomovirus/genética , Enfermedades de las Plantas/virología , Enfermedades de las Plantas/genética , Polimorfismo de Nucleótido Simple/genética , Sitios de Carácter Cuantitativo/genética , Genoma de Planta/genética , Genotipo , Marcadores GenéticosRESUMEN
KEY MESSAGE: The investigation of MYMIV-infected mung bean leaf apoplast revealed viral genome presence, increased EVs secretion, and altered stress-related metabolite composition, providing comprehensive insights into plant-virus interactions. The apoplast, an extracellular space around plant cells, plays a vital role in plant-microbe interactions, influencing signaling, defense, and nutrient transport. While the involvement of apoplast and extracellular vesicles (EVs) in RNA virus infection is documented, the role of the apoplast in plant DNA viruses remains unclear. This study explores the apoplast's role in mungbean yellow mosaic India virus (MYMIV) infection. Our findings demonstrate the presence of MYMIV genomic components in apoplastic fluid, suggesting potential begomovirus cell-to-cell movement via the apoplast. Moreover, MYMIV infection induces increased EVs secretion into the apoplast. NMR-based metabolomics reveals altered metabolic profiles in both apoplast and symplast in response to MYMIV infection, highlighting key metabolites associated with stress and defense mechanisms. The data show an elevation of α- and ß-glucose in both apoplast and symplast, suggesting a shift in glucose utilization. Interestingly, this increase in glucose does not contribute to the synthesis of phenolic compounds, potentially influencing the susceptibility of mung bean to MYMIV. Fructose levels increase in the symplast, while apoplastic sucrose levels rise significantly. Symplastic aspartate levels increase, while proline exhibits elevated concentration in the apoplast and reduced concentration in the cytosol, suggesting a role in triggering a hypersensitive response. These findings underscore the critical role of the apoplast in begomovirus infection, providing insights for targeted viral disease management strategies.
Asunto(s)
Begomovirus , Enfermedades de las Plantas , Hojas de la Planta , Vigna , Begomovirus/fisiología , Hojas de la Planta/virología , Hojas de la Planta/metabolismo , Vigna/virología , Vigna/metabolismo , Vigna/genética , Enfermedades de las Plantas/virología , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/virología , Metabolómica/métodos , Genoma ViralRESUMEN
The female genital tract (FGT) is an important site of human immunodeficiency virus (HIV) infection. Discerning the nature of HIV-specific local immune responses is crucial for identifying correlates of protection in HIV-exposed seronegative (HESN) individuals. The present study involved a comprehensive analysis of soluble immune mediators, secretory immunoglobulins (sIg), natural killer (NK) cells, CXCR5+ CD8+ T cells, T follicular helper (Tfh) cells, and T regulatory cells (Tregs) in the vaginal mucosa as well as the nature and composition of the cervicovaginal microbiome in HESN women. We found significantly elevated antiviral cytokines, soluble immunoglobulins, and increased frequencies of activated NK cells, CXCR5+ CD8+ T cells, and Tfh cells in HESN females compared to HIV-unexposed healthy (UH) women. Analysis of the genital microbiome of HESN women revealed a greater bacterial diversity and increased abundance of Gardnerella spp. in the mucosa. The findings suggest that the female genital tract of HESN females represents a microenvironment equipped with innate immune factors, antiviral mediators, and critical T cell subsets that protect against HIV infection. IMPORTANCE The vast majority of human immunodeficiency virus (HIV) infections across the world occur via the sexual route. The genital tract mucosa is thus the primary site of HIV replication, and discerning the nature of HIV-specific immune responses in this compartment is crucial. The role of the innate immune system at the mucosal level in exposed seronegative individuals and other HIV controllers remains largely unexplored. This understanding can provide valuable insights to improve vaccine design. We investigated mucosal T follicular helper (Tfh) cells, CXCR5+ CD8+ T cells, natural killer (NK) cells subsets, soluble immune markers, and microbiome diversity in HIV-exposed seronegative (HESN) women. We found a significantly higher level of mucosal CXCR5+ CD8+ T cells, CD4+ Tfh cells, activated NK cell subsets, and antiviral immune cell mediators in HESN women. We also found a higher abundance of Gardnerella spp., microbiome dysbiosis, and decreased levels of inflammatory markers to be associated with reduced susceptibility to HIV infection. Our findings indicate that increased distribution of mucosal NK cells, CXCR5+ CD8+ T cells, Tfh cells, and soluble markers in HIV controllers with a highly diverse cervicovaginal microbiome could contribute effectively to protection against HIV infection. Overall, our findings imply that future vaccine design should emphasize inducing these highly functional cell types at the mucosal sites.
Asunto(s)
Infecciones por VIH/inmunología , Microbiota , Vigna/microbiología , Adulto , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Linfocitos T CD8-positivos/inmunología , Citocinas/genética , Citocinas/inmunología , Mucosa Esofágica/inmunología , Mucosa Esofágica/microbiología , Mucosa Esofágica/virología , Femenino , Infecciones por VIH/genética , Infecciones por VIH/microbiología , Infecciones por VIH/virología , Seronegatividad para VIH , Humanos , Inmunidad Mucosa , Células Asesinas Naturales/inmunología , Células T Auxiliares Foliculares/inmunología , Linfocitos T Reguladores/inmunología , Vigna/inmunología , Vigna/virología , Adulto JovenRESUMEN
BACKGROUND: Pregnant women using antiretrovirals (ARVs) may have persistent vaginal viral shedding, which could be associated with sexual and perinatal HIV transmission. However, there are scant data on vaginal viral load (VVL) in pregnant women with undetectable plasma viral load (PVL). METHODS: This study was a post hoc analysis of an open-label randomized trial to evaluate the virologic response of 2 ART regimens. The participants were ART-naive women living with HIV initiating ART regimens between 20 and 36 weeks of pregnancy recruited at 19 clinical sites in 6 countries. Participants were randomized to receive 400 mg of raltegravir 2 times a day or 600 mg of efavirenz 4 times a day in addition to 150 mg of lamivudine and 300 mg of zidovudine 2 times a day. VVL and PVL tests were performed at every study visit. The primary outcome measures were HIV-1 PVL and VVL at maternal study week 4 and rates of perinatal HIV transmission. RESULTS: A total of 408 were enrolled, of whom 323 had VVL samples 4 weeks after enrollment and were included in this analysis. Among women with undetectable/nonquantifiable PVL during ART, the overall rate of quantifiable VVL at week 4 was 2.54% (7/275). Of the 275 with nonquantifiable PVL, 99.1% (115/116) and 96.2% (153/159) had nonquantifiable VVL in the efavirenz and raltegravir arms, respectively. None of the 7 women with quantifiable VVL at the week 4 study visit transmitted HIV to their infants. CONCLUSIONS: Detectable VVL in pregnant women with undetectable/nonquantifiable PVL while receiving ART was rare and not associated with perinatal HIV transmission.
Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Terapia Antirretroviral Altamente Activa/métodos , Infecciones por VIH/tratamiento farmacológico , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Vigna/virología , Carga Viral/efectos de los fármacos , Esparcimiento de Virus , Adulto , Alquinos/uso terapéutico , Benzoxazinas/uso terapéutico , Ciclopropanos/uso terapéutico , Farmacorresistencia Viral , Femenino , Infecciones por VIH/transmisión , Infecciones por VIH/virología , Humanos , Lactante , Lamivudine/uso terapéutico , Embarazo , Mujeres Embarazadas , Raltegravir Potásico/uso terapéutico , Zidovudina/uso terapéuticoRESUMEN
In this study, the complete nucleotide sequence of a Brazilian isolate of cowpea severe mosaic virus (CPSMV) is presented for the first time. To date, the CPSMV-DG isolate, from the USA, is the only one with the complete known genome. High-throughput sequencing (Illumina HiSeq) and Sanger sequencing of the total RNA extract from a cowpea plant collected in Teresina city, Brazil, revealed the genome sequence of the CPSMV-Ter1 isolate. RNA-1 and RNA-2 are, respectively, 5921 and 3465 nucleotides (nt) long without the poly(A) tail, and show 77.91% and 76.08% nt sequence identity with CPSMV-DG, considered the type isolate of the species. The open reading frames (ORFs) were determined and the cleavage sites of the polyproteins were predicted. Although the two isolates show a similar genomic organization, there was a low percentage of sequence identity between Ter1 and DG. Furthermore, pairwise comparisons of a partial RNA-1 fragment between CPSMV-Ter1 and 11 CPSMV isolates from Brazil indicated 94.6 to 94.8% nt and 98.9% to 99.4% aa sequence identities.
Asunto(s)
Comovirus/genética , Genoma Viral , Brasil , Comovirus/aislamiento & purificación , ARN Viral , Análisis de Secuencia de ARN , Vigna/virología , Secuenciación Completa del GenomaRESUMEN
Yellow Mosaic Disease (YMD) in mungbean [Vigna radiata (L.) R. Wilczek] is one of the most damaging diseases in Asia. In the northern part of India, the YMD is caused by Mungbean Yellow Mosaic India Virus (MYMIV), while in southern India this is caused by Mungbean Yellow Mosaic Virus (MYMV). The molecular mechanism of YMD resistance in mungbean remains largely unknown. In this study, RNA-seq analysis was conducted between a resistant (PMR-1) and a susceptible (Pusa Vishal) mungbean genotype under infected and control conditions to understand the regulatory network operating between mungbean-YMV. Overall, 76.8 million raw reads could be generated in different treatment combinations, while mapping rate per library to the reference genome varied from 86.78% to 93.35%. The resistance to MYMIV showed a very complicated gene network, which begins with the production of general PAMPs (pathogen-associated molecular patterns), then activation of various signaling cascades like kinases, jasmonic acid (JA) and brassinosteroid (BR), and finally the expression of specific genes (like PR-proteins, virus resistance and R-gene proteins) leading to resistance response. The function of WRKY, NAC and MYB transcription factors in imparting the resistance against MYMIV could be established. The string analysis also revealed the role of proteins involved in kinase, viral movement and phytoene synthase activity in imparting YMD resistance. A set of novel stress-related EST-SSRs are also identified from the RNA-Seq data which may be used to find the linked genes/QTLs with the YMD resistance. Also, 11 defence-related transcripts could be validated through quantitative real-time PCR analysis. The identified gene networks have led to an insight about the defence mechanism operating against MYMIV infection in mungbean which will be of immense use to manage the YMD resistance in mungbean.
Asunto(s)
Begomovirus/fisiología , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/virología , Vigna/genética , Vigna/virología , Resistencia a la Enfermedad , Redes Reguladoras de Genes , RNA-Seq , TranscriptomaRESUMEN
BACKGROUND: Milk vetch dwarf virus (MDV) is an important ssDNA virus which causes yellowing, stunting and leaf rolling symptoms on legumes. In China, the virus causes great economic losses and has recently been found to infect tobacco. The expansion of its host range and its ability to spread rapidly has given rise to the urgent need for a sensitive, specific and rapid diagnostic assay that can assist in effective disease control. METHODS: Assays based on the polymerase chain reaction combined with lateral flow strip detection (PCR-LFS) and recombinase polymerase amplification combined with LFS (RPA-LFS) were developed targeting the coat protein (CP) gene of MDV. RESULTS: The PCR and RPA assays could detect respectively 103 copies or 101 copies of MDV by agarose gel electrophoresis. The PCR-LFS and RPA-LFS assays developed could both detect as few as 101 copies per reaction at 37 °C. Both methods could detect MDV in crude leaf extracts. CONCLUSIONS: The RPA-LFS assay developed is a rapid, sensitive and specific method for detecting MDV, which is convenient and has great potential for use in the field.
Asunto(s)
Cromatografía de Afinidad/métodos , Nanovirus/aislamiento & purificación , Técnicas de Amplificación de Ácido Nucleico/métodos , Recombinasas/genética , Vigna/virología , Proteínas de la Cápside/genética , China , Cromatografía de Afinidad/instrumentación , Nanovirus/genética , Enfermedades de las Plantas/virología , Hojas de la Planta/virología , Sensibilidad y EspecificidadRESUMEN
KEY MESSAGE: Cowpea miRNAs and Argonaute genes showed differential expression patterns in response to CPSMV challenge Several biotic stresses affect cowpea production and yield. CPSMV stands out for causing severe negative impacts on cowpea. Plants have two main induced immune systems. In the basal system (PTI, PAMP-triggered immunity), plants recognize and respond to conserved molecular patterns associated with pathogens (PAMPs). The second type (ETI, Effector-triggered immunity) is induced after plant recognition of specific factors from pathogens. RNA silencing is another important defense mechanism in plants. Our research group has been using biochemical and proteomic approaches to learn which proteins and pathways are involved and could explain why some cowpea genotypes are resistant whereas others are susceptible to CPSMV. This current study was conducted to determine the role of cowpea miRNA in the interaction between a resistant cowpea genotype (BRS-Marataoã) and CPSMV. Previously identified and deposited plant microRNA sequences were used to find out all possible microRNAs in the cowpea genome. This search detected 617 mature microRNAs, which were distributed in 89 microRNA families. Next, 4 out of these 617 miRNAs and their possible target genes that encode the proteins Kat-p80, DEAD-Box, GST, and SPB9, all involved in the defense response of cowpea to CPSMV, had their expression compared between cowpea leaves uninoculated and inoculated with CPSMV. Additionally, the differential expression of genes that encode the Argonaute (AGO) proteins 1, 2, 4, 6, and 10 is reported. In summary, the studied miRNAs and AGO 2 and AGO4 associated genes showed differential expression patterns in response to CPSMV challenge, which indicate their role in cowpea defense.
Asunto(s)
Comovirus/fisiología , Regulación de la Expresión Génica de las Plantas , MicroARNs/genética , Vigna/genética , Vigna/virología , Secuencia de Bases , Genoma de Planta , MicroARNs/metabolismo , Conformación de Ácido Nucleico , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/virología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estabilidad del ARN/genética , Estándares de ReferenciaRESUMEN
Soybean yellow mottle mosaic virus (SYMMV) is a newly identified member of the genus Gammacarmovirus from grain legumes in India. As the modes of transmission of this virus have not been described, we assessed the possibility of SYMMV to be transmitted through seed collected from field infected mungbean plants and mechanically sap inoculated French bean plants using serological and molecular techniques followed by progeny assays. Direct antigen coated enzyme linked immunosorbent assay (DAC-ELISA) and reverse transcription polymerase chain reaction (RT-PCR) results are inconsistent with field infected mungbean seed tissues to ensure seed transmissibility irrespective of seed number used. Seed from mechanical sap inoculated French bean showed higher absorbance values in DAC-ELISA and amplification corresponding to replicase, movement and coat protein regions of SYMMV genome. The relative accumulation of SYMMV was higher in pod walls, immature seed and stamens and stigma of mechanical sap inoculated French bean. Progeny assays with infected seed revealed the seed transmissibility of SYMMV at the rate of 63.33% in mungbeanand 73.33% in French bean. Mechanical sap inoculation of mungbean progeny seedlings on French bean cv. Pusa Parvati produced characteristic symptoms of SYMMV. The results obtained from this study demonstrate that SYMMV is seed borne in nature and can be transmitted to next generation seedlings. This is the first report of seed transmission of SYMMV in mungbean and French bean.
Asunto(s)
Enfermedades de las Plantas/virología , Semillas/virología , Tombusviridae/genética , Vigna/virología , Genoma Viral , India , Phaseolus/virología , Filogenia , Plantones/virologíaRESUMEN
In the rapidly evolving field of nanotechnology, plant virus nanoparticles (pVNPs) are emerging as powerful tools in diverse applications ranging from biomedicine to materials science. The proteinaceous structure of plant viruses allows the capsid structure to be modified by genetic engineering and/or chemical conjugation with nanoscale precision. This means that pVNPs can be engineered to display peptides and proteins on their external surface, including immunodominant peptides derived from pathogens allowing pVNPs to be used for active immunization. In this context, pVNPs are safer than VNPs derived from mammalian viruses because there is no risk of infection or reversion to pathogenicity. Furthermore, pVNPs can be produced rapidly and inexpensively in natural host plants or heterologous production platforms. In this review, we discuss the use of pVNPs for the delivery of peptide antigens to the host immune in pre-clinical studies with the final aim of promoting systemic immunity against the corresponding pathogens. Furthermore, we described the versatility of plant viruses, with innate immunostimulatory properties, in providing a huge natural resource of carriers that can be used to develop the next generation of sustainable vaccines.
Asunto(s)
Nanopartículas/química , Nanotecnología/métodos , Nicotiana/genética , Virus de Plantas/inmunología , Vacunas de Partículas Similares a Virus/administración & dosificación , Vigna/genética , Animales , Antígenos Virales/química , Antígenos Virales/genética , Antígenos Virales/inmunología , Cápside/química , Cápside/inmunología , Evaluación Preclínica de Medicamentos , Ingeniería Genética/métodos , Humanos , Inmunización , Inmunogenicidad Vacunal , Ratones , Nanopartículas/administración & dosificación , Péptidos/química , Péptidos/genética , Péptidos/inmunología , Virus de Plantas/genética , Nicotiana/virología , Vacunas de Subunidad , Vacunas de Partículas Similares a Virus/biosíntesis , Vacunas de Partículas Similares a Virus/genética , Vigna/virologíaRESUMEN
Infection with Cowpea severe mosaic virus (CPSMV) represents one of the main limitations for cowpea (Vigna unguiculata L. Walp.) productivity due to the severity of the disease symptoms, frequency of incidence, and difficulties in dissemination control. This study aimed to identify the proteins and metabolic pathways associated with the susceptibility and resistance of cowpea plants to CPSMV. Therefore, we treated the seeds of a naturally susceptible cowpea genotype (CE-31) with the mutagenic agent ethyl methane sulfonate (EMS) and compared the secondary leaf proteomic profile of the mutagenized resistant plants inoculated with CPSMV (MCPI plant group) to those of the naturally susceptible cowpea genotype CE-31 inoculated (CPI) and noninoculated (CPU) with CPSMV. MCPI responded to CPSMV by accumulating proteins involved in the oxidative burst, increasing H2O2 generation, promoting leaf cell death (LCD), increasing the synthesis of defense proteins, and decreasing host factors important for the establishment of CPSMV infection. In contrast, CPI accumulated several host factors that favor CPSMV infection and did not accumulate H2O2 or present LCD, which allowed CPSMV replication and systemic dissemination. Based on these results, we propose that the differential abundance of defense proteins and proteins involved in the oxidative burst, LCD, and the decrease in cowpea protein factors required for CPSMV replication are associated with the resistance trait acquired by the MCPI plant group.
Asunto(s)
Comovirus/fisiología , Resistencia a la Enfermedad , Peróxido de Hidrógeno/metabolismo , Mutagénesis , Hojas de la Planta/virología , Vigna/metabolismo , Vigna/virología , Muerte Celular/genética , Muerte Celular/fisiología , Resistencia a la Enfermedad/genética , Resistencia a la Enfermedad/fisiología , Metanosulfonato de Etilo/química , Metanosulfonato de Etilo/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/fisiología , Ontología de Genes , Homeostasis/efectos de los fármacos , Homeostasis/genética , Homeostasis/fisiología , Interacciones Huésped-Patógeno/efectos de los fármacos , Interacciones Huésped-Patógeno/genética , Interacciones Huésped-Patógeno/fisiología , Mutágenos/química , Mutágenos/farmacología , Oxidación-Reducción/efectos de los fármacos , Fotosíntesis/efectos de los fármacos , Fotosíntesis/genética , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/virología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Hojas de la Planta/fisiología , Proteínas de Plantas/efectos de los fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Mapas de Interacción de Proteínas , Proteoma/efectos de los fármacos , Proteoma/genética , Proteoma/metabolismo , Proteoma/fisiología , Vigna/genética , Vigna/fisiología , Replicación ViralRESUMEN
The coat protein (CP) is the only structural protein present in the polyprotein of bean common mosaic virus. The well known characteristics of the CP are self-oligomerization and nucleic acid binding activity. The studies of the coat protein mutants revealed that the oligomeric property of CP solely depends on the amino-terminal residues and the nucleic acid binding domain present at the 194-202 residue position. The 3'UTR RNA of the virus showed high binding affinity with the RNA binding domain as compared to the 5'UTR RNA. Further, the intrinsic fluorescence study of the CP also suggested that the N- and C-terminal of CP contains a highly disordered region. The present study also illustrates that the coat protein contains a conserved RNA binding pocket among the potyviruses, but displays divergent oligomerization propensities due to the difference in residue at the N- and C-terminal.
Asunto(s)
Proteínas de la Cápside/química , Proteínas de la Cápside/genética , Potyvirus/química , Potyvirus/genética , ARN Viral/genética , Regiones no Traducidas 3' , Regiones no Traducidas 5' , Secuencia de Aminoácidos , Proteínas Portadoras/química , Proteínas Portadoras/genética , Proteínas de Unión al ARN/química , Proteínas de Unión al ARN/genética , Semillas/virología , Vigna/virología , Ensamble de VirusRESUMEN
Mungbean (Vigna radiata) and ricebean (V. umbellata) were utilized to obtain an inter-specific recombinant inbred line (RIL) population with the objective of detecting quantitative trait loci (QTL) associated with mungbean yellow mosaic virus (MYMV) resistance. To precisely map QTLs, accurate genetic linkage maps are essential. In the present study, genotyping-by-sequencing (GBS) platform was utilized to develop the genetic linkage map. The map contained 538 single nucleotide polymorphism (SNP) markers, consisted of 11 linkage groups and spanned for 1291.7 cM with an average marker distance of 2.40 cM. The individual linkage group ranged from 90.2 to 149.1 cM in length, and the SNP markers were evenly distributed in the genetic linkage map, with 30-79 SNP markers per chromosome. The QTL analysis using the genetic map and 2 years (2015 and 2016) of phenotyping data identified five QTLs with phenotypic variation explained (PVE) from 10.11 to 20.04%. Of these, a QTL on chromosome 4, designated as qMYMV4-1, was major and stably detected in the same marker interval in both years. This QTL region harbours possible candidate genes for controlling MYMV resistance. The linkage map and QTL/gene (s) for MYMV resistance identified in this study should be useful for QTL fine mapping and cloning for further studies.
Asunto(s)
Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/genética , Sitios de Carácter Cuantitativo/genética , Vigna/genética , Begomovirus/patogenicidad , Mapeo Cromosómico , Ligamiento Genético , Repeticiones de Microsatélite/genética , Fenotipo , Enfermedades de las Plantas/virología , Polimorfismo de Nucleótido Simple/genética , Vigna/virologíaRESUMEN
INTRODUCTION: Emerging viral diseases, most of which are zoonotic, pose a significant threat to global health. There is a critical need to identify potential new viral pathogens and the challenge is to identify the reservoirs from which these viruses might emerge. Deep sequencing of invertebrate transcriptomes has revealed a plethora of viruses, many of which represent novel lineages representing both plant and animal viruses and little is known about the potential threat that these viruses pose. METHODS: Providence virus, an insect virus, was used to establish a productive infection in Vigna unguiculata (cowpea) plants. Providence virus particles purified from these cowpea plants were used to infect two mammalian cell lines. FINDINGS: Here, we present evidence that Providence virus, a non-enveloped insect RNA virus, isolated from a lepidopteran midgut cell line can establish a productive infection in plants as well as in animal cells. The observation that Providence virus can readily infect both plants and mammalian cell culture lines demonstrates the ability of an insect RNA virus to establish productive infections across two kingdoms, in plants and invertebrate and vertebrate animal cell lines. CONCLUSIONS: The study highlights the potential of phytophagous insects as reservoirs for viral re-assortment and that plants should be considered as reservoirs for emerging viruses that may be potentially pathogenic to humans.
Asunto(s)
Lepidópteros/virología , Células Vegetales/virología , Infecciones por Virus ARN/metabolismo , Vigna/virología , Animales , Células HeLa , Humanos , Células MCF-7 , Virus ARNRESUMEN
A new bipartite begomovirus (family Geminiviridae) was detected on cowpea (Vigna unguiculata) plants exhibiting bright golden mosaic symptoms on leaves under field conditions in Brazil. Complete consensus sequences of DNA-A and DNA-B components of an isolate of the virus (PE-088) were obtained by nanopore sequencing and confirmed by Sanger sequencing. The genome components presented the typical genomic organization of New World (NW) begomoviruses. Pairwise sequence comparisons revealed low levels of identity with other begomovirus species previously reported infecting cowpea around the world. Phylogenetic analysis using complete sequences of DNA-A components revealed that the closest relatives of PE-088 (85-87% nucleotide sequence identities) were three legume-infecting begomoviruses from Brazil: bean golden mosaic virus, macroptilium common mosaic virus and macroptilium yellow vein virus. According to the current classification criteria, PE-088 represents a new species in the genus Begomovirus, tentatively named as cowpea bright yellow mosaic virus (CoBYMV).
Asunto(s)
Begomovirus/clasificación , Begomovirus/genética , Genoma Viral/genética , Enfermedades de las Plantas/virología , Hojas de la Planta/virología , Vigna/virología , Secuencia de Bases , Begomovirus/aislamiento & purificación , ADN Viral/genética , Filogenia , Análisis de Secuencia de ADNRESUMEN
In nature, plants are simultaneously challenged by biotic and abiotic stresses. However, little is known about the effects of these combined stresses for most crops. This work aimed to evaluate the responsed of the virus-resistant cowpea genotype BRS-Marataoã to the exposure of salt stress combined with CPSMV infection. Cowpea plants were exposed to 200â¯mM NaCl either simultaneously (SV plant group) or 24â¯h prior to the CPSMV infection [S(24â¯h)V plant group]. Physiological, biochemical, and proteomic analyses at 2 and 6â¯days post salt stress (DPS) revealed that cowpea significantly reprogrammed its cellular metabolism. Indeed, plant size, photosynthetic parameters (net photosynthesis, transpiration rate, stomatal conductance, and internal CO2 partial pressure) and chlorophyll and carotenoid contents were reduced in S(24â¯h)V compared to SV. Moreover, accumulation of viral particles at 6 DPS in S(24â¯h)V was observed indicating that the salt stress imposed prior to virus infection favors viral particle proliferation. Proteomic analysis showed differential contents of 403 and 330 proteins at 2 DPS and 6 DPS, respectively, out of 733 differentially abundant proteins between the two plant groups. The altered leaf proteins are involved in energy and metabolism, photosynthesis, stress response, and oxidative burst. BIOLOGICAL SIGNIFICANCE: This is an original study in which a virus-resistant cowpea genotype (BRS-Marataoã) was (i) exposed simultaneously to 200â¯mM NaCl and inoculation with CPSMV (SV plant group) or (ii) exposed to 200â¯mM NaCl stress 24â¯h prior to inoculation with CPSMV [S(24â¯h)V plant group]. The purpose was to shed light on how this CPSMV resistant cowpea responded to the combined stresses. Numerous key proteins and associated pathways were altered in the cowpea plants challenged with both stresses, but unexpectedly, the salt stress imposed 24â¯h prior to CPSMV inoculation allowed viral proliferation, turning the cowpea genotype from resistant to susceptible.
Asunto(s)
Comovirus/metabolismo , Genotipo , Enfermedades de las Plantas/virología , Proteínas de Plantas/metabolismo , Estrés Salino , Vigna , Proteómica , Vigna/genética , Vigna/metabolismo , Vigna/virologíaRESUMEN
The survival of viruses partly relies on their ability to self-assemble inside host cells. Although coarse-grained simulations have identified different pathways leading to assembled virions from their components, experimental evidence is severely lacking. Here, we use time-resolved small-angle X-ray scattering to uncover the nonequilibrium self-assembly dynamics of icosahedral viral capsids packaging their full RNA genome. We reveal the formation of amorphous complexes via an en masse pathway and their relaxation into virions via a synchronous pathway. The binding energy of capsid subunits on the genome is moderate (~7kBT0, with kB the Boltzmann constant and T0 = 298 K, the room temperature), while the energy barrier separating the complexes and the virions is high (~ 20kBT0). A synthetic polyelectrolyte can lower this barrier so that filled capsids are formed in conditions where virions cannot build up. We propose a representation of the dynamics on a free energy landscape.
Asunto(s)
Bromovirus/fisiología , Proteínas de la Cápside/metabolismo , Cápside/metabolismo , Ensamble de Virus , Microscopía por Crioelectrón , Genoma Viral , Concentración de Iones de Hidrógeno , Polielectrolitos/química , ARN/análisis , Dispersión de Radiación , Electricidad Estática , Termodinámica , Vigna/virología , Virión/metabolismo , Rayos XRESUMEN
Vigna mungo (L.)Hepper is an economically important leguminous crop in south-east Asia. However, its production is severely affected by Mungbean yellow mosaic India virus (MYMIV). It is well established that methyl jasmonate (MeJA) is effective in inducing resistance against pathogens in several plants. To assess the role of MeJA in developing MYMIV tolerance in V. mungo, we analysed time-dependent biochemical and molecular responses of MYMIV susceptible V. mungo after exogenous application of different MeJA concentrations, followed by MYMIV infection. Our analysis revealed that exogenous application of different concentrations of MeJA resulted in decreased levels of malondialdehyde with higher membrane stability index values in MYMIV susceptible V. mungo, suggesting the protective role of MeJA through restoring the membrane stability. Moreover, the level of expression of different antioxidative enzymes revealed that exogenous MeJA is also very effective in ROS homeostasis maintenance. Enhanced expressions of the defence marker genes lipoxygenase and phenylalanine ammonia-lyase and the reduced expression of the MYMIV coat-protein encoding gene in all MeJA treated plants post MYMIV infection revealed that exogenous application of MeJA is effective for MYMIV tolerance in V. mungo. Our findings provide new insights into the physiological and molecular mechanisms of MYMIV tolerance in Vigna induced by MeJA.
Asunto(s)
Acetatos/farmacología , Begomovirus , Ciclopentanos/farmacología , Oxilipinas/farmacología , Enfermedades de las Plantas/virología , Vigna/virología , Begomovirus/efectos de los fármacos , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/prevención & control , Vigna/efectos de los fármacos , Vigna/inmunologíaRESUMEN
Cowpea is an important grain legume crop of Africa, Latin America, and Southeast Asia. Leaf curl and golden mosaic diseases caused by Mungbean yellow mosaic India virus (MYMIV) have emerged as most devastating viral diseases of cowpea in Southeast Asia. In this study, we employed RNA interference (RNAi) strategy to control cowpea-infecting MYMIV. For this, we generated transgenic cowpea plants harbouring three different intron hairpin RNAi constructs, containing the AC2, AC4 and fusion of AC2 and AC4 (AC2+AC4) of seven cowpea-infecting begomoviruses. The T0 and T1 transgenic cowpea lines of all the three constructs accumulated transgene-specific siRNAs. Transgenic plants were further assayed up to T1 generations, for resistance to MYMIV using agro-infectious clones. Nearly 100% resistance against MYMIV infection was observed in transgenic lines, expressing AC2-hp and AC2+AC4-hp RNA, when compared with untransformed controls and plants transformed with empty vectors, which developed severe viral disease symptoms within 3 weeks. The AC4-hp RNA expressing lines displayed appearance of milder symptoms after 5 weeks of MYMIV-inoculation. Northern blots revealed a positive correlation between the level of transgene-specific siRNAs accumulation and virus resistance. The MYMIV-resistant transgenic lines accumulated nearly zero or very low titres of viral DNA. The transgenic cowpea plants had normal phenotype with no yield penalty in greenhouse conditions. This is the first demonstration of RNAi-derived resistance to MYMIV in cowpea.