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Potassium (K+) plays a crucial role as a macronutrient in the growth and development of plants. Studies have definitely determined the vital roles of K+ in response to pathogen invasion. Our previous investigations revealed that rice plants infected with rice grassy stunt virus (RGSV) displayed a reduction in K+ content, but the mechanism by which RGSV infection subverts K+ uptake remains unknown. In this study, we found that overexpression of RGSV P1, a specific viral protein encoded by viral RNA1, results in enhanced sensitivity to low K+ stress and exhibits a significantly lower rate of K+ influx compared to wild-type rice plants. Further investigation revealed that RGSV P1 interacts with OsCIPK23, an upstream regulator of Shaker K+ channel OsAKT1. Moreover, we found that the P1 protein recruits the OsCIPK23 to the Cajal bodies (CBs). In vivo assays demonstrated that the P1 protein competitively binds to OsCIPK23 with both OsCBL1 and OsAKT1. In the nucleus, the P1 protein enhances the binding of OsCIPK23 to OsCoilin, a homologue of the signature protein of CBs in Arabidopsis, and facilitates their trafficking through these CB structures. Genetic analysis indicates that mutant in oscipk23 suppresses RGSV systemic infection. Conversely, osakt1 mutants exhibited increased sensitivity to RGSV infection. These findings suggest that RGSV P1 hinders the absorption of K+ in rice plants by recruiting the OsCIPK23 to the CB structures. This process potentially promotes virus systemic infection but comes at the expense of inhibiting OsAKT1 activity.
Assuntos
Oryza , Doenças das Plantas , Proteínas de Plantas , Potássio , Proteínas Virais , Oryza/metabolismo , Oryza/genética , Oryza/virologia , Potássio/metabolismo , Doenças das Plantas/virologia , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas Virais/metabolismo , Proteínas Virais/genéticaRESUMO
Introduction: Accessory breast cancer (ABC) is an extremely rare condition, particularly the presence of triple-negative ABC with ipsilateral invasive in situ breast cancer. Binary breast tumors are controversial in terms of surgical methods and comprehensive treatment. Case presentation: We share the case of a 64-year-old postmenopausal woman who presented with an underarm mass for 3 months. Ultrasonography and computed tomography suggested possible breast cancer with axillary lymph node metastasis. The patient underwent a left modified radical mastectomy combined with axillary lymph node dissection. The postoperative pathology confirmed a binary tumor, prompting us to initiate comprehensive treatment. Conclusion: We present the treatment approach for a rare case of triple-negative para-breast cancer complicated with carcinoma in situ of the breast, hoping to contribute new therapeutic ideas for the treatment of this disease.
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Chinese bayberry (Myrica rubra) is an economically significant fruit tree native to eastern Asia and widely planted in south-central China. However, studies about the viruses infecting M. rubra remain largely lacking. In the present study, we employed the metatranscriptomic method to identify viruses in M. rubra leaves exhibiting yellowing and irregular margin symptoms collected in Fuzhou, a city located in China's Fujian province in the year 2022. As a consequence, a novel member of the genus Totivirus was identified and tentatively named "Myrica rubra associated totivirus 1" (MRaTV1). The genome sequencing of MRaTV1 was determined by overlapping reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The two deduced proteins encoded by MRaTV1 have the highest amino acid (aa) sequence identity to the coat protein (CP) and RNA-dependent RNA polymerase (RdRP) of Panax notoginseng virus A (PNVA), a member of the genus Totivirus within the family Totiviridae, at 49.7% and 61.7%, respectively. According to the results of the phylogenetic tree and the species demarcation criteria of the International Committee on Taxonomy of Viruses (ICTV) for the genus Totivirus, MRaTV1 is considered a new member of the genus Totivirus.
Assuntos
Myrica , Totivirus , Myrica/genética , Filogenia , Genoma Viral , Sequência de BasesRESUMO
Passionfruit (Passiflora edulis) is a significant fruit crop in the commercial sector, owing to its high nutritional and medicinal value. The advent of high-throughput genomics sequencing technology has led to the publication of a vast amount of passionfruit omics data, encompassing complete genome sequences and transcriptome data under diverse stress conditions. To facilitate the efficient integration, storage, and analysis of these large-scale datasets, and to enable researchers to effectively utilize these omics data, we developed the first passionfruit genome database (PGD). The PGD platform comprises a diverse range of functional modules, including a genome browser, search function, heatmap, gene expression patterns, various tools, sequence alignment, and batch download, thereby providing a user-friendly interface. Additionally, supplementary practical tools have been developed for the PGD, such as gene family analysis tools, gene ontology (GO) terms, a pathway enrichment analysis, and other data analysis and mining tools, which enhance the data's utilization value. By leveraging the database's robust scalability, the intention is to continue to collect and integrate passionfruit omics data in the PGD, providing comprehensive and in-depth support for passionfruit research. The PGD is freely accessible via http://passionfruit.com.cn .
Assuntos
Passiflora , Diagnóstico Pré-Implantação , Feminino , Gravidez , Humanos , Passiflora/genética , Genômica , Genoma , Análise de Sequência , Bases de Dados GenéticasRESUMO
Objective: This study aimed to assess the efficacy of Endoscopic Retrograde Cholangiopancreatography (ERCP), common bile duct exploration, and percutaneous transhepatic cholangiography combined with common bile duct exploration for treating choledocholithiasis with acute cholangitis, to guide management strategies. Methods: A retrospective evaluation was conducted on a cohort of 283 inpatients diagnosed with choledocholithiasis and acute cholangitis at the affiliated hospital. Patients were categorized into three groups: Group A (ERCP group), Group B(common bile duct exploration group), and Group C(PTCD combine common bile duct exploration group.) Parameters such as hepatic function recovery, inflammation level control, blood loss, postoperative hospital duration, and postoperative complications were compared. Results: All groups exhibited notable reductions in postoperative biochemical parameters including alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), total bilirubin (TBIL), and WBC (P < 0.05). Group A had the least blood loss(P < 0.05), and shortest hospital stay(P < 0.05), but a higher incidence of pancreatitis(P < 0.05), with a total of 8 cases occurred(7.3%). Group C had a shorter hospital stay compared to Group B(P < 0.05). Conclusion: For patients with fewer and smaller common bile duct stones and milder symptoms, it is recommended to primarily choose endoscopic retrograde cholangiopancreatography (ERCP), endoscopic sphincterotomy (EST), and endoscopic nasobiliary drainage (ENBD), it procedures offer quicker recovery and cause minimal trauma. For patients with numerous, larger common bile duct stones but stable conditions, bile duct exploration is recommended. For those with severe conditions and significant inflammation, PTCD and common bile duct exploration are advised.
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Many geminiviruses, including members of the genus Begomovirus, produce a protein known as C4 or AC4. Whereas C4/AC4 typically consists of more than 80 amino acid residues, a few are much shorter. The significance of these shorter C4/AC4 proteins in viral infection and why the virus maintains their abbreviated length is not yet understood. The AC4 of the begomovirus Tomato leaf curl Hsinchu virus contains only 65 amino acids, but it extends to 96 amino acids when the natural termination codon is replaced with a normal codon. We discovered that both interrupting and extending AC4 were harmful to tomato leaf curl Hsinchu virus (ToLCHsV). The extended AC4 (EAC4) also showed a reduced ability to promote the infection of the heterologous virus Potato virus X than the wild-type AC4. When the wild-type AC4 was fused with yellow fluorescent protein (AC4-YFP), it was predominantly found in chloroplasts, whereas EAC4-YFP was mainly localized to the cell periphery. These results suggest that ToLCHsV's AC4 protein is important for viral infection, and the virus may benefit from the abbreviated length, because it may lead to chloroplast localization. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Begomovirus , Geminiviridae , Viroses , Begomovirus/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo , Aminoácidos/metabolismo , Doenças das PlantasRESUMO
Geminiviruses are a family of single-stranded DNA viruses that cause significant yield losses in crop production worldwide. Transcription start site (TSS) mapping is crucial in understanding the gene expression mechanisms of geminiviruses. However, this often requires costly and laborious experiments. Rice stripe virus (RSV) has a mechanism called cap-snatching, whereby it cleaves cellular mRNAs and uses the 5' cleavage product, a capped-RNA leader (CRL), as primers for transcription. Our previous work demonstrated that RSV snatches CRLs from geminiviral mRNAs in co-infected plants, providing a convenient and powerful approach to map the TSSs of geminiviruses. However, co-infections are not always feasible for all geminiviruses. In this study, we evaluated the use of in vitro cap-snatching of RSV for the same purpose, using tomato yellow leaf curl virus (TYLCV) as an example. We incubated RNA extracted from TYLCV-infected plants with purified RSV ribonucleoproteins in a reaction mixture that supports in vitro cap-snatching of RSV. The RSV mRNAs produced in the reaction were deep sequenced. The CRLs snatched by RSV allowed us to locate 28 TSSs in TYLCV. These results provide support for using RSV's in vitro cap-snatching to map geminiviral TSSs.
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Geminiviridae , Tenuivirus , Tenuivirus/genética , Tenuivirus/metabolismo , Geminiviridae/genética , RNA Viral/genética , Sítio de Iniciação de Transcrição , RNA Mensageiro/genéticaRESUMO
OBJECTIVE: To investigate the efficacy and clinical application advantage of omental tamponade with vascular pedicle combined with Laparoscopic fenestration for the treatment of diaphragmatic hepatic cyst. METHODS: A total of 56 patients with diaphragmatic hepatic cysts underwent laparoscopic surgery in a single tertiary academic medical center from January 2010 to October 2020, including 21 patients (non-omental group) underwent laparoscopic fenestration of liver cysts, and 36 patients underwent laparoscopic liver cyst fenestration combined with vascular pedicle omentum tamponade (omental group). The general conditions and follow-up results of the two groups were compared and annalyzed. RESULTS: The operation time of the omental group was longer than that of the non-omental group (P = 1.358E-4). There was no significant difference in postoperative complications, postoperative laboratory values and hospital costs (P>0.05). The length of hospital stay in omental group was shorter than that in non-omental group (P = 0.034). In the omental group, recurrence occurred in 1 of 35 patients (4.65%) who were followeded up 12 months after surgery. In the non-omental group, of the 21 patients followed, 3 patients (14.28%) recurred 6 months after surgery, and 8 patients (38.10%) recurred 12 months after surgery. CONCLUSION: It is an effective method to prevent the recurrence of diaphragmatic hepatic cyst after laparoscopic fenestration by packing the cyst with vascularized omentum.
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Cistos , Laparoscopia , Hepatopatias , Doenças Torácicas , Humanos , Omento/cirurgia , Cistos/cirurgia , Hepatopatias/cirurgia , Laparoscopia/métodos , Fígado , Doenças Torácicas/cirurgiaRESUMO
Intracellular potassium (K+ ) transported by plants under the action of a number of transport proteins is crucial for plant survival under distinct abiotic and biotic stresses. A correlation between K+ status and disease incidence has been found in many studies, but the roles of K+ in regulating disease resistance to viral diseases remain elusive. Here, we report that HIGH-AFFINITY K+ TRANSPORTER 5 (OsHAK5) regulates the infection of rice grassy stunt virus (RGSV), a negative-sense single-stranded bunyavirus, in rice (Oryza sativa). We found the K+ content in rice plants was significantly inhibited on RGSV infection. Meanwhile, a dramatic induction of OsHAK5 transcripts was observed in RGSV-infected rice plants and in rice plants with K+ deficiency. Genetic analysis indicated that disruption of OsHAK5 facilitated viral pathogenicity. In contrast, overexpression of OsHAK5 enhanced resistance to RGSV infection. Our analysis of reactive oxygen species (ROS) including H2 O2 and O2- , by DAB and NBT staining, respectively, indicated that RGSV infection as well as OsHAK5 overexpression increased ROS accumulation in rice leaves. The accumulation of ROS is perhaps involved in the induction of host resistance against RGSV infection in OsHAK5 transgenic overexpression rice plants. Furthermore, RGSV-encoded P3 induced OsHAK5 promoter activity, suggesting that RGSV P3 is probably an elicitor for the induction of OsHAK5 transcripts during RGSV infection. These findings indicate the crucial role of OsHAK5 in host resistance to virus infection. Our results may be exploited in the future to increase crop yield as well as improve host resistance via genetic manipulations.
Assuntos
Oryza , Tenuivirus , Regulação da Expressão Gênica de Plantas , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Potássio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tenuivirus/genéticaRESUMO
Bunyaviruses cleave host cellular mRNAs to acquire cap structures for their own mRNAs in a process called cap-snatching. How bunyaviruses interact with cellular mRNA surveillance pathways such as nonsense-mediated decay (NMD) during cap-snatching remains poorly understood, especially in plants. Rice stripe virus (RSV) is a plant bunyavirus threatening rice production in East Asia. Here, with a newly developed system allowing us to present defined mRNAs to RSV in Nicotiana benthamiana, we found that the frequency of RSV to target nonsense mRNAs (nsRNAs) during cap-snatching was much lower than its frequency to target normal mRNAs. The frequency of RSV to target nsRNAs was increased by virus-induced gene silencing of UPF1 or SMG7, each encoding a protein component involved in early steps of NMD (in an rdr6 RNAi background). Coincidently, RSV accumulation was increased in the UPF1- or SMG7-silenced plants. These data indicated that the frequency of RSV to target nsRNAs during cap-snatching is restricted by NMD. By restricting the frequency of RSV to target nsRNAs, NMD may impose a constraint to the overall cap-snatching efficiency of RSV. Besides a deeper understanding for the cap-snatching of RSV, these findings point to a novel role of NMD in plant-bunyavirus interactions.
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Orthobunyavirus , Tenuivirus , Proteínas de Transporte/metabolismo , Degradação do RNAm Mediada por Códon sem Sentido/genética , Orthobunyavirus/genética , Orthobunyavirus/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Tenuivirus/genéticaRESUMO
Two new alkaloids, named hositisines A (1) and B (2), with two known alkaloids (3 and 4) were isolated from the stems of Ormosia hosiei Hemsl. et Wils. Their structures were confirmed by UV, HRESIMS, NMR spectra. The absolute configurations of 1 and 2 were determined by quantum ECD calculation and ECD, respectively. Compounds 1-3 could significantly reduce the LDH release at the concentration 50 µM, which showed they could strongly protect the PC12 cells exposed to oxygen and glucose deprivation/reoxygenation (OGD/R) injury.
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Alcaloides/isolamento & purificação , Fabaceae/química , Caules de Planta/química , Alcaloides/química , Animais , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Glucose/deficiência , L-Lactato Desidrogenase/metabolismo , Oxigênio/farmacologia , Células PC12 , Espectroscopia de Prótons por Ressonância Magnética , RatosRESUMO
Tomato mosaic virus (ToMV) is a tobamovirus affecting solanaceous crops worldwide. The process of its emergence, however, is poorly understood. Here, Bayesian phylogenetic framework was employed to reconstruct the phylogeography of ToMV in Eurasia. The results showed that the ToMV in Europe, Middle East and East Asia has been evolving at a rate of 4.05 × 10-4 substitutions/site/year (95% credibility interval 2.43 × 10-4 - 5.62 × 10-4). Their most recent common ancestor (MRCA), most probably first appeared in Europe, was dated to around 1757 Common Era. The first introduction of ToMV into Middle East occurred in 1920s, with Europe as the source, while the first introduction of ToMV into East Asia occurred shortly afterwards, with Middle East as the source. From about 1950 onwards, inter-regional migrations of ToMV between Europe, Middle East and East Asia have been common. Overall, these data provide a glimpse into the phylogeographic history of ToMV in Eurasia.
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Tobamovirus/genética , Tobamovirus/fisiologia , Teorema de Bayes , Produtos Agrícolas/virologia , Europa (Continente) , Evolução Molecular , Ásia Oriental , Solanum lycopersicum/virologia , Oriente Médio , Filogenia , Filogeografia , Doenças das Plantas/virologiaRESUMO
Dithiocarbamates (DTCs) pesticides were extensively used as fungicides in a variety of crops during their growth, storage and shipment. The DTCs residue in foods will seriously harm human health. In this study, a novel multicolor colorimetric sensor was developed for visual screening of total DTCs (total of ziram, thiram and zineb) based on sulfhydryl-mediated growth of gold nanobipyramids (AuNBPs). We demonstrated that DTCs can absorb on AuNBPs seed's surface via the formation of Au-S bonds and thus impede the 8-hydroxyquinoline (8-HQ)-promoted AuNBPs growth, which generates DTCs concentration-corresponding color changes. The developed sensor has vivid color changes, short analysis time, higher sensitivity and excellent specificity. It can be used to detect as low as 50 nM of total DTCs by bare eye observation and 17-18 nM of total DTCs by UV-visible spectrometry. By using the multicolor sensor, we have successfully screened total DTCs in apple and black tea by bare eye observation, and detected total DTCs in apple and black tea by UV-visible spectrometry with a recovery of 90%-104% and a relative standard deviation (RSD, n = 5) < 5%. The results obtained with our method consisted well with those obtained with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), verifying that our method had good accuracy and reliability. Especially, the visual detection limit of our method is much lower than the maximum residue limit of total DTCs in vegetable and fruits. All above features make our sensor a promising method for rapid on-site screening of total DTCs in vegetable and fruits by only bare eye observation.
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Resíduos de Praguicidas , Praguicidas , Colorimetria , Ouro , Humanos , Praguicidas/análise , Reprodutibilidade dos Testes , Espectrometria de Massas em TandemRESUMO
Different hypotheses have been proposed to interpret the observed unusual ITS (internal transcribed spacer) sequences in Ophiocordyceps sinensis. The coexistence of diverged ITS paralogs in a single genome was previously shown by amplifying the ITS region from mono-ascospore isolates using specific primers designed for different ITS paralog groups. Among those paralogs, are AT-biased ITS sequences which were hypothesized to result from repeat-induced point mutation (RIP). This is a process that detects and mutates repetitive DNA and frequently leads to epigenetic silencing, and these mutations have been interpreted as pseudogenes. Here we investigate the occurrence and frequency of ITS pseudogenes in populations of O. sinensis using large-scale sampling, and discusses the implications of ITS pseudogenes for fungal phylogenetic and evolutionary studies. Our results demonstrate a wide distribution of ITS pseudogenes amongst different geographic populations, and indicate how ITS pseudogenes can contribute to the reconstruction of the evolutionary history of the species.
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Like their animal-infecting counterparts, plant bunyaviruses use capped RNA leaders cleaved from host cellular mRNAs to prime viral genome transcription in a process called cap-snatching, but in vivo systems to investigate the details of this process are lacking for them. Here, we report that Rice stripe tenuivirus (RSV) and Tomato spotted wilt tospovirus (TSWV) cleave capped RNA leaders from mRNAs transiently expressed by agroinfiltration, which makes it possible to artificially deliver defined cap donors to the two plant bunyaviruses with unprecedented convenience. With this system, some ideas regarding how plant bunyaviruses select and use capped RNA leaders can be tested easily. We were also able to obtain clear evidence that the capped RNA leaders selected by TSWV are generally longer than those by RSV. TSWV frequently uses the prime-and-realign mechanism in transcription primed by capped RNA leaders shorter than a certain length, like that has been demonstrated recently for RSV.
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Bunyaviridae/genética , Capuzes de RNA/genética , Capuzes de RNA/metabolismo , Regiões 3' não Traduzidas , Agrobacterium tumefaciens/genética , Agrobacterium tumefaciens/metabolismo , Pareamento de Bases , Bunyaviridae/metabolismo , Genoma Viral , Folhas de Planta/virologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Viral/biossíntese , RNA Viral/genética , Especificidade da Espécie , Tenuivirus/genética , Tenuivirus/metabolismo , Nicotiana/virologia , Tospovirus/genética , Tospovirus/metabolismo , Transcrição GênicaRESUMO
Cucumber mosaic virus (CMV) caused huge agricultural impact on Passiflora edulis. However, the interactions between CMV and P. edulis are poorly unknown, which lead to lack of prevention and control measures. In this study, we identified the infection of CMV in P. edulis through modern small RNA sequencing (sRNA-seq) technology combined with traditional electron microscope and polymerase chain reaction (PCR) methods. We also confirmed CMV infection adversely affected or modulated the contents of phytochemicals and further injured the development of P. edulis; inversely, P. edulis modulated its resistance to CMV stress by increasing the levels of secondary metabolites and the activities of antioxidant enzymes components. This is of significant importance to understand the interaction between virus infection and plant host.
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Cucumovirus/fisiologia , Interações Hospedeiro-Patógeno , Passiflora/química , Passiflora/virologia , Compostos Fitoquímicos/química , Doenças das Plantas/virologia , Antioxidantes/química , Antioxidantes/metabolismo , Frutas/virologia , Fenótipo , Compostos Fitoquímicos/análise , Folhas de Planta/virologia , Análise de Sequência de RNARESUMO
Geminiviruses constitute a family of plant viruses with characteristic twinned quasi-icosahedral virions and a small circular DNA genome. Geminiviruses, especially begomoviruses, cause substantial economic losses in tropical and subtropical regions globally. Geminiviruses use the host's transcriptional mechanisms to synthesize their mRNAs. They are considered as an attractive model to understand the transcription mechanism of their host plants. Experiments were conducted to identify transcriptional start sites (TSSs) of the three begomoviruses, i.e., Cotton leaf curl Multan virus (CLCuMuV), Corchorus yellow vein virus (CoYVV), and Ramie mosaic virus (RamV). We first rub-inoculated Rice stripe tenuivirus (RSV), a segmented negative-sense RNA virus that uses cap-snatching to produce capped viral mRNAs, into N. benthamiana. After the inoculation, RSV-infected N. benthamiana were super-infected by CoYVV, CLCuMuV, or RamV, respectively. The capped-RNA leaders snatched by RSV were obtained by determining the 5'-ends of RSV mRNA with high throughput sequencing. Afterwards, snatched capped-RNA leaders of RSV were mapped onto the genome of each begomovirus and those matching the begomoviral genome were considered to come from the 5' ends of assumed begomoviral mRNAs. In this way, TSSs of begomoviruses were obtained. After mapping these TSSs onto the genome of the respective begomovirus, it was found very commonly that a begomovirus can use many different TSSs to transcribe the same gene, producing many different mRNA isoforms containing the corresponding open reading frames (ORFs).
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Begomovirus/genética , Southern Blotting/métodos , DNA Viral/genética , Nicotiana/virologia , Transcrição Gênica , Animais , Begomovirus/patogenicidade , Coinfecção/virologia , Genoma Viral , Hemípteros/virologia , Doenças das Plantas/virologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Viral/genética , Tenuivirus/genética , Tenuivirus/patogenicidade , Nicotiana/genética , Sítio de Iniciação de TranscriçãoRESUMO
A cytorhabdovirus, tentatively named "strawberry-associated virus 1" (SaV1), was identified in strawberry (Fragaria ananassa Duch.), and its complete genome sequence was determined. Its negative-sense single-stranded RNA genome is composed of 14,159 nucleotides and contains eight open reading frames (ORFs) in the canonical order 3'-N-P-P3-M-G-P6-P7-L-5. The ORFs are separated by conserved intergenic sequences, and the genome coding region is flanked by 3' and 5' untranslated regions of 179 and 856 nt, respectively. SaV1 N and L genes shares 32-57% and 38-64% amino acid sequence identity with those of nine reported cytorhabdoviruses, respectively. Phylogenetic analysis showed that SaV1 clustered with high confidence with representative cytorhabdoviruses and is most closely related to tomato yellow mottle-associated virus. There are two additional small genes of unknown function between the G and L genes. We propose that SaV1 should be considered a member of a novel species in the genus Cytorhabdovirus, family Rhabdoviridae.
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Fragaria/virologia , Genoma Viral , Doenças das Plantas/virologia , Rhabdoviridae/genética , DNA Intergênico/genética , Fases de Leitura Aberta , Filogenia , Rhabdoviridae/classificação , Rhabdoviridae/isolamento & purificação , Proteínas Virais/genética , Sequenciamento Completo do GenomaRESUMO
Viral infections universally rely on numerous hijacked host factors to be successful. It is therefore possible to control viral infections by manipulating host factors that are critical for viral replication. Given that host genes may play essential roles in certain cellular processes, any successful manipulations for virus control should cause no or mild effects on host fitness. We previously showed that a group of positive-strand RNA viruses enrich phosphatidylcholine (PC) at the sites of viral replication. Specifically, brome mosaic virus (BMV) replication protein 1a interacts with and recruits a PC synthesis enzyme, phosphatidylethanolamine methyltransferase, Cho2p, to the viral replication sites that are assembled on the perinuclear endoplasmic reticulum (ER) membrane. Deletion of the CHO2 gene inhibited BMV replication by 5-fold; however, it slowed down host cell growth as well. Here, we show that an engineered Cho2p mutant supports general PC synthesis and normal cell growth but blocks BMV replication. This mutant interacts and colocalizes with BMV 1a but prevents BMV 1a from localizing to the perinuclear ER membrane. The mislocalized BMV 1a fails to induce the formation of viral replication complexes. Our study demonstrates an effective antiviral strategy in which a host lipid synthesis gene is engineered to control viral replication without comprising host growth.
Assuntos
Fosfatidiletanolamina N-Metiltransferase/genética , Fosfatidiletanolamina N-Metiltransferase/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Bromovirus/metabolismo , Retículo Endoplasmático/metabolismo , Engenharia Genética/métodos , Fosfatidilcolinas/metabolismo , Fosfolipídeos/genética , Fosfolipídeos/metabolismo , RNA Viral/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas Virais/metabolismo , Replicação Viral/genéticaRESUMO
Cucumber green mottle mosaic virus (CGMMV), an emerging tobamovirus, has caused serious disease outbreaks to cucurbit crops in several countries, including the United States. Although CGMMV is seed-borne, the mechanism of its transmission from a contaminated seed to germinating seedling is still not fully understood, and the most suitable seed health assay method has not been well established. To evaluate the mechanism of seed transmissibility, using highly contaminated watermelon seeds collected from CGMMV-infected experimental plants, bioassays were conducted in a greenhouse through seedling grow-out and by mechanical inoculation. Through natural seedling grow-out, we did not observe seed transmission of CGMMV to germinating seedlings. However, efficient transmission of CGMMV was observed using bioassays on melon plants through mechanical inoculation of seed extract prepared from CGMMV-contaminated seeds. Understanding the seed-borne property and the ease of mechanical transmission of CGMMV from a contaminated seed to seedling is an important finding. In comparative evaluation of various laboratory techniques for seed health assays, we found that enzyme-linked immunosorbent assay and loop-mediated isothermal amplification were the most sensitive and reliable methods to detect CGMMV on cucurbit seeds. Because CGMMV is a seed-borne and highly contagious virus, a new infection might not result in a natural seedling grow-out; it could occur through mechanical transmission from contaminated seeds. Therefore, a sensitive seed health test is necessary to ensure CGMMV-free seed lots are used for planting.