scholarly journals Light Quantity and Photosystem Function Mediate Host Susceptibility to Turnip mosaic virus Via a Salicylic Acid–Independent Mechanism

2011 ◽  
Vol 24 (3) ◽  
pp. 315-327 ◽  
Author(s):  
A. Manfre ◽  
M. Glenn ◽  
A. Nuñez ◽  
R. A. Moreau ◽  
C. Dardick
Keyword(s):  
Salicylic Acid ◽  
Mosaic Virus ◽  
Cell Movement ◽  
Time Lapse ◽  
Defense Responses ◽  
Turnip Mosaic Virus ◽  
Host Susceptibility ◽  
Systemic Movement ◽  
Underlying Mechanisms ◽  
Light Deficiency

Evidence going as far back as the early part of the 20th century suggests that both light and chloroplast function may play key roles in host susceptibility to viruses. Despite the long history of such work, confirmation of these phenomena and a determination of the underlying mechanisms remain elusive. Here, we revisited these questions using modern imaging technologies to study the susceptibility of Nicotiana benthamiana to Turnip mosaic virus (TuMV). We found that both light deficiency and photosystem impairment increased the susceptibility of N. benthamiana to TuMV infection. Time-lapse photography studies indicated that, under these conditions, rub-inoculated plants exhibited greater numbers of infection foci and more rapid foci development. The rate of systemic movement was also accelerated though cell-to-cell movement appeared unchanged. Inhibition of salicylic acid (SA)-mediated defense responses is not likely responsible for changes in susceptibility because SA and pathogen response-1 gene induction were not affected by light deficiency or chloroplast impairment and treatment of plants with SA had no measureable impact on TuMV infection. Taken together, these data suggest that both light and optimal chloroplast function influence virus infection either by limiting the cellular resources needed by TuMV to establish replication complexes or the host's ability to activate SA-independent defenses.

scholarly journals Genome-Wide Identification Reveals That Nicotiana benthamiana Hypersensitive Response (HR)-Like Lesion Inducing Protein 4 (NbHRLI4) Mediates Cell Death and Salicylic Acid-Dependent Defense Responses to Turnip Mosaic Virus

2021 ◽  
Vol 12 ◽  
Author(s):  
Xinyang Wu ◽  
Yuchao Lai ◽  
Shaofei Rao ◽  
Lanqing Lv ◽  
Mengfei Ji ◽  
...  
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Mosaic Virus ◽  
Hypersensitive Response ◽  
Nicotiana Benthamiana ◽  
Defense Responses ◽  
Turnip Mosaic Virus ◽  
Genome Wide ◽  
Transient Overexpression ◽  
Basal Immunity

Hypersensitive response (HR)-like cell death is an important mechanism that mediates the plant response to pathogens. In our previous study, we reported that NbHIR3s regulate HR-like cell death and basal immunity. However, the host genes involved in HR have rarely been studied. Here, we used transcriptome sequencing to identify Niben101Scf02063g02012.1, an HR-like lesion inducing protein (HRLI) in Nicotiana benthamiana that was significantly reduced by turnip mosaic virus (TuMV). HRLIs are uncharacterized proteins which may regulate the HR process. We identified all six HRLIs in N. benthamiana and functionally analyzed Niben101Scf02063g02012.1, named NbHRLI4, in response to TuMV. Silencing of NbHRLI4 increased TuMV accumulation, while overexpression of NbHRLI4 conferred resistance to TuMV. Transient overexpression of NbHRLI4 caused cell death with an increase in the expression of salicylic acid (SA) pathway genes but led to less cell death level and weaker immunity in plants expressing NahG. Thus, we have characterized NbHRLI4 as an inducer of cell death and an antiviral regulator of TuMV infection in a SA-mediated manner.

scholarly journals Susceptibility and Symptom Development in Arabidopsis thaliana to Tobacco mosaic virus Is Influenced by Virus Cell-to-Cell Movement

2000 ◽  
Vol 13 (10) ◽  
pp. 1139-1144 ◽  
Author(s):  
Christopher D. Dardick ◽  
Sheetal Golem ◽  
James N. Culver
Keyword(s):  
Arabidopsis Thaliana ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Cell Movement ◽  
Recessive Gene ◽  
Defense Responses ◽  
Systemic Movement ◽  
Pathogenesis Related ◽  
Symptom Phenotype ◽  
Dominant Genes

To identify host factors that regulate susceptibility to Tobacco mosaic virus(TMV), 14 Arabidopsis thaliana ecotypes were screened for their ability to support TMV systemic movement. The susceptibility phenotypes observed included one ecotype that permitted rapid TMV movement accompanied by symptoms, nine ecotypes that allowed a slower intermediate rate of systemic movement without symptoms, and four ecotypes that allowed little or no systemic TMV movement. Molecular comparisons between ecotypes representing the rapid (Shahdara), intermediate (Col-1), and slow (Tsu-1) movement phenotypes revealed a positive correlation between the ability of TMV to move cell to cell and its speed of systemic movement. Additionally, protoplasts prepared from all three ecotypes supported similar levels of TMV replication, indicating that viral replication did not account for differences in systemic movement. Furthermore, induction of the pathogenesis-related genes PR-1 and PR-5 occurred only in the highly susceptible ecotype Shahdara, demonstrating that reduced local and systemic movement in Col-1 and Tsu-1 was not due to the activation of known host defense responses. Genetic analysis of F2 progeny derived from crosses made between Shahdara and Tsu-1 or Col-1 and Tsu-1 showed the faster cell-to-cell movement phenotypes of Shahdara and Col-1 segregated as single dominant genes. In addition, the Shahdara symptom phenotype segregated independently as a single recessive gene. Taken together, these findings suggest that, within Arabidopsis ecotypes, at least two genes modulate susceptibility to TMV.

scholarly journals NbALD1 mediates resistance to turnip mosaic virus by regulating the accumulation of salicylic acid and the ethylene pathway in Nicotiana benthamiana

2019 ◽  
Vol 20 (7) ◽  
pp. 990-1004 ◽  
Author(s):  
Shu Wang ◽  
Kelei Han ◽  
Jiejun Peng ◽  
Jinping Zhao ◽  
Liangliang Jiang ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Mosaic Virus ◽  
Nicotiana Benthamiana ◽  
Turnip Mosaic Virus

scholarly journals The potyviral protein 6K1 reduces plant protease activity during Turnip mosaic virus infection

2021 ◽  
Author(s):  
Sayanta Bera ◽  
Gabriella D Arena ◽  
Swayamjit Ray ◽  
Sydney A. Flannigan ◽  
Clare L Casteel
Keyword(s):  
Mosaic Virus ◽  
Transient Expression ◽  
Cysteine Protease ◽  
Protease Activity ◽  
Cell Movement ◽  
Early Time ◽  
Turnip Mosaic Virus ◽  
Infection Process ◽  
Plant Protease ◽  
In Trans

Potyviral genomes encode just 11 major proteins and multifunctionality is associated to most of these proteins at different stages of virus life cycle. The potyviral protein 6K1 is required for potyvirus replication at the early stages of viral infection and may mediate cell-to-cell movement at later stages.Our study demonstrates that the 6K1 protein from Turnip mosaic virus (TuMV) reduces the abundance of transcripts related to jasmonic acid biosynthesis and transcripts that encode cysteine protease inhibitors when expressed in trans in Nicotiana benthamiana relative to controls. Furthermore, 6K1 stability increases when lipoxygenase and cysteine protease activity is inhibited chemically, linking a mechanism to the rapid turnover of 6K1 when expressed in trans. Using transient expression, we show 6K1 is degraded rapidly at early time points in the infection process, whereas at later stages of infection protease activity is reduced and 6K1 becomes more stable, resulting in higher TuMV accumulation in systemic leaves. There was no impact of 6K1 transient expression on TuMV accumulation in local leaves. Together, these results suggest a novel function for the TuMV 6K1 protein which has not been reported previously and enhances our understanding of the complex interactions occurring between plants and potyviruses.

scholarly journals The Two Conserved Cysteine Residues of the Triple Gene Block Protein 2 Are Critical for Both Cell-to-Cell and Systemic Movement of Bamboo mosaic virus

2009 ◽  
Vol 22 (11) ◽  
pp. 1379-1388 ◽  
Author(s):  
Yang-Hao Tseng ◽  
Hsiu-Ting Hsu ◽  
Yuan-Lin Chou ◽  
Chung-Chi Hu ◽  
Na-Sheng Lin ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Mosaic Virus ◽  
Outer Surface ◽  
Transmembrane Protein ◽  
Triple Gene Block ◽  
Cell Movement ◽  
Gene Block ◽  
Systemic Movement ◽  
Granular Vesicles ◽  
Triple Gene Block Protein

The triple gene block protein 2 (TGBp2) of Bamboo mosaic virus (BaMV) is a transmembrane protein which is known to be required for the cell-to-cell movement of potexviruses. This protein has two conserved Cys residues, Cys-109 and Cys-112, at its C-terminal tail, which is supposed to be exposed on the outer surface of the endoplasmic reticulum (ER) membrane and ER-derived granular vesicles. In this study, we investigated the importance of these two Cys residues on the cell-to-cell and systemic movement of BaMV. Our results indicate that the Cys-to-Ala substitutions in TGBp2 make the cell-to-cell movement of BaMV relatively inefficient and the systemic movement of BaMV severely inhibited. Moreover, the defect in systemic movement is attributed to the inefficient transport of viral RNA in the phloem of petiole. Clearly, TGBp2 is critical not only for the cell-to-cell but also for the systemic movement of BaMV. In addition, the conserved Cys residues are important for the functioning of TGBp2.

scholarly journals Exploring the Multifunctional Roles of Odontoglossum Ringspot Virus P126 in Facilitating Cymbidium Mosaic Virus Cell-to-Cell Movement during Mixed Infection

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1552
Author(s):  
Shu-Chuan Lee ◽  
Hsuan Pai ◽  
Ying-Wen Huang ◽  
Meng-Hsun He ◽  
Yun-Lin Song ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Mixed Infection ◽  
Protein Function ◽  
Cell Movement ◽  
Ringspot Virus ◽  
Cdna Clones ◽  
Cymbidium Mosaic Virus ◽  
Odontoglossum Ringspot Virus ◽  
Underlying Mechanisms ◽  
Viral Titers

Synergistic interactions among viruses, hosts and/or transmission vectors during mixed infection can alter viral titers, symptom severity or host range. Viral suppressors of RNA silencing (VSRs) are considered one of such factors contributing to synergistic responses. Odontoglossum ringspot virus (ORSV) and cymbidium mosaic virus (CymMV), which are two of the most significant orchid viruses, exhibit synergistic symptom intensification in Phalaenopsis orchids with unilaterally enhanced CymMV movement by ORSV. In order to reveal the underlying mechanisms, we generated infectious cDNA clones of ORSV and CymMV isolated from Phalaenopsis that exerted similar unilateral synergism in both Phalaenopsis orchid and Nicotiana benthamiana. Moreover, we show that the ORSV replicase P126 is a VSR. Mutagenesis analysis revealed that mutation of the methionine in the carboxyl terminus of ORSV P126 abolished ORSV replication even though some P126 mutants preserved VSR activity, indicating that the VSR function of P126 alone is not sufficient for viral replication. Thus, P126 functions in both ORSV replication and as a VSR. Furthermore, P126 expression enhanced cell-to-cell movement and viral titers of CymMV in infected Phalaenopsis flowers and N. benthamiana leaves. Taking together, both the VSR and protein function of P126 might be prerequisites for unilaterally enhancing CymMV cell-to-cell movement by ORSV.

scholarly journals Salicylic Acid-Induced Resistance to Cucumber mosaic virus in Squash and Arabidopsis thaliana: Contrasting Mechanisms of Induction and Antiviral Action

2005 ◽  
Vol 18 (5) ◽  
pp. 428-434 ◽  
Author(s):  
Carl N. Mayers ◽  
Kian-Chung Lee ◽  
Catherine A. Moore ◽  
Sek-Man Wong ◽  
John P. Carr
Keyword(s):  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Induced Resistance ◽  
Host Species ◽  
Cell Movement ◽  
Signal Transduction Pathway ◽  
Model Systems ◽  
Antimycin A

Salicylic acid (SA)-induced resistance to Cucumber mosaic virus (CMV) in tobacco (Nicotiana tabacum) results from inhibition of systemic virus movement and is induced via a signal transduction pathway that also can be triggered by antimycin A, an inducer of the mitochondrial enzyme alternative oxidase (AOX). In Arabidopsis thaliana, inhibition of CMV systemic movement also is induced by SA and antimycin A. These results indicate that the mechanisms underlying induced resistance to CMV in tobacco and A. thaliana are very similar. In contrast to the situation in tobacco and A. thaliana, in squash (Cucurbita pepo), SA-induced resistance to CMV results from inhibited virus accumulation in directly inoculated tissue, most likely through inhibition of cell-to-cell movement. Furthermore, neither of the AOX inducers antimycin A or KCN induced resistance to CMV in squash. Additionally, AOX inhibitors that compromise SAinduced resistance to CMV in tobacco did not inhibit SAinduced resistance to the virus in squash. The results show that different host species may use significantly different approaches to resist infection by the same virus. These findings also imply that caution is required when attempting to apply findings on plant-virus interactions from model systems to a wider range of host species.

Systemic Hypersensitive Resistance to Turnip mosaic virus in Brassica juncea is Associated With Multiple Defense Responses, Especially Phloem Necrosis and Xylem Occlusion

Plant Disease ◽  
2016 ◽  
Vol 100 (7) ◽  
pp. 1261-1270 ◽  
Author(s):  
Eviness P. Nyalugwe ◽  
Martin J. Barbetti ◽  
Peta L. Clode ◽  
Roger A. C. Jones
Keyword(s):  
Hydrogen Peroxide ◽  
Light Microscopy ◽  
Mosaic Virus ◽  
Brassica Juncea ◽  
Cross Sections ◽  
Defense Responses ◽  
Turnip Mosaic Virus ◽  
Hypersensitive Resistance ◽  
Phloem Necrosis ◽  
Hydrogen Peroxide Accumulation

Systemic hypersensitive resistance (SHR) caused by Turnip mosaic virus (TuMV) was studied by light microscopy and histochemical analysis in stem cross sections of Brassica juncea (Indian mustard) plants. Ten TuMV isolates were inoculated to leaves of susceptible line JM 06006, cv. Oasis CI, which carries TuMV systemic hypersensitivity gene TuRBJU 01, and F3 progeny plants obtained from a cross between them. Systemic mosaic (SM) symptoms were induced by all 10 isolates in plants of JM 06006, and by resistance-breaking isolate NSW-3 in all cv. Oasis CI and F3 plants. With the other nine isolates, cv. Oasis CI plants developed SHR while F3 progeny plants segregated for both phenotypes; mock-inoculated control plants never became infected. Presence of SHR did not delay systemic invasion as this commenced within 2 hours after inoculation (hai) and was almost complete by 72 hai regardless of whether plants subsequently developed SHR or SM. When stem cross sections sampled 9 to 12 days after inoculation were examined for the plant defense responses, phloem necrosis, hydrogen peroxide accumulation, and additional lignin deposition, sections from plants with SHR demonstrated all of these characteristics, but sections from plants with SM or mock-inoculation did not. Based on consolidated data from all isolates except NSW-3, stems developing SHR had significantly more occluded xylem vessels (P < 0.001) compared with stems from plants developing SM or mock-inoculated plants. Both light microscopy and histochemical tests with phloroglucinol-HCl and toluidine blue O indicated that the xylem occlusions could be gels. Thus, phloem necrosis, xylem occlusion, lignification, and hydrogen peroxide accumulation were all associated with the SHR in B. juncea plants carrying TuMV hypersensitivity gene TuRBJU 01. In addition, virus inclusion bodies were fewer in sections from plants with SHR. Phloem necrosis was apparently acting as the primary cause of SHR and xylem occlusion as an important secondary cause.

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