scholarly journals The Intriguing Conundrum of a Nonconserved Multifunctional Protein of Citrus Tristeza Virus That Interacts with a Viral Long Non-Coding RNA

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2129
Author(s):  
Sung-Hwan Kang ◽  
Vicken Aknadibossian ◽  
Laxmi Kharel ◽  
Shachinthaka D. Dissanayaka Mudiyanselage ◽  
Ying Wang ◽  
...  
Keyword(s):  
Virus Infection ◽  
Citrus Tristeza Virus ◽  
Biological Significance ◽  
Wild Type Virus ◽  
Virus Protein ◽  
Non Coding Rna ◽  
Long Non Coding Rna ◽  
Tristeza Virus ◽  
Citrus Tristeza

Citrus tristeza virus (CTV), the largest non-segmented plant RNA virus, has several peculiar features, among which is the production of a 5′-terminal long non-coding RNA (lncRNA) termed low-molecular-weight tristeza 1 (LMT1). In this study, we found that p33, a unique viral protein that performs multiple functions in the virus infection cycle, specifically binds LMT1, both in vivo and in vitro. These results were obtained through the expression of p33 under the context of the wild type virus infection or along with a mutant CTV variant that does not produce LMT1 as well as via ectopic co-expression of p33 with LMT1 in Nicotiana benthamiana leaves followed by RNA immunoprecipitation and rapid amplification of cDNA ends assays. Further experiments in which a recombinant p33 protein and an in vitro transcribed full-length LMT1 RNA or its truncated fragments were subjected to an electrophoretic mobility shift assay demonstrated that p33 binds to at least two distinct regions within LMT1. To the best of our knowledge, this is the first report of a plant virus protein binding to a lncRNA produced by the same virus. The biological significance of the interaction between these two viral factors is discussed.

scholarly journals A Long Non-Coding RNA of Citrus tristeza virus: Role in the Virus Interplay with the Host Immunity

Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 436 ◽  
Author(s):  
Sung-Hwan Kang ◽  
Yong-Duo Sun ◽  
Osama O. Atallah ◽  
Jose Carlos Huguet-Tapia ◽  
Jerald D. Noble ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Ectopic Expression ◽  
Oxidase Gene ◽  
Non Coding Rna ◽  
Systemic Spread ◽  
Pathogenesis Related ◽  
Long Time ◽  
Long Non Coding Rna ◽  
Tristeza Virus ◽  
Citrus Tristeza

During infection, Citrus tristeza virus (CTV) produces a non-coding subgenomic RNA referred to as low-molecular-weight tristeza 1 (LMT1), which for a long time has been considered as a by-product of the complex CTV replication machinery. In this study, we investigated the role of LMT1 in the virus infection cycle using a CTV variant that does not produce LMT1 (CTV-LMT1d). We showed that lack of LMT1 did not halt virus ability to replicate or form proper virions. However, the mutant virus demonstrated significantly reduced invasiveness and systemic spread in Nicotiana benthamiana as well as an inability to establish infection in citrus. Introduction of CTV-LMT1d into the herbaceous host resulted in elevation of the levels of salicylic acid (SA) and SA-responsive pathogenesis-related genes beyond those upon inoculation with wild-type (WT) virus (CTV-WT). Further analysis showed that the LMT1 RNA produced by CTV-WT or via ectopic expression in the N. benthamiana leaves suppressed SA accumulation and up-regulated an alternative oxidase gene, which appeared to mitigate the accumulation of reactive oxygen species. To the best of our knowledge, this is the first report of a plant viral long non-coding RNA being involved in counter-acting host response by subverting the SA-mediated plant defense.

A possible role of CTV.20 gene methylation in response to Citrus tristeza virus infection

2017 ◽  
Vol 150 (2) ◽  
pp. 527-532 ◽  
Author(s):  
Valentina Fanelli ◽  
C. De Giovanni ◽  
M. Saponari ◽  
P. Leonetti ◽  
L. Ricciardi ◽  
...  
Keyword(s):  
Virus Infection ◽  
Citrus Tristeza Virus ◽  
Gene Methylation ◽  
Tristeza Virus ◽  
Citrus Tristeza

Stem pitting and seedling yellows symptoms of Citrus tristeza virus infection may be determined by minor sequence variants

Virus Genes ◽  
2007 ◽  
Vol 36 (1) ◽  
pp. 241-249 ◽  
Author(s):  
Silvija Černi ◽  
Jelena Ruščić ◽  
Gustavo Nolasco ◽  
Živko Gatin ◽  
Mladen Krajačić ◽  
...  
Keyword(s):  
Virus Infection ◽  
Citrus Tristeza Virus ◽  
Sequence Variants ◽  
Minor Sequence ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

scholarly journals Minor Coat and Heat Shock Proteins Are Involved in the Binding of Citrus Tristeza Virus to the Foregut of Its Aphid Vector, Toxoptera citricida

2016 ◽  
Vol 82 (21) ◽  
pp. 6294-6302 ◽  
Author(s):  
N. Killiny ◽  
S. J. Harper ◽  
S. Alfaress ◽  
C. El Mohtar ◽  
W. O. Dawson
Keyword(s):  
Heat Shock ◽  
Citrus Tristeza Virus ◽  
Viral Proteins ◽  
Aphid Vector ◽  
Toxoptera Citricida ◽  
Shock Proteins ◽  
Tristeza Virus ◽  
Minor Coat Protein ◽  
Citrus Tristeza

ABSTRACTVector transmission is a critical stage in the viral life cycle, yet for most plant viruses how they interact with their vector is unknown or is explained by analogy with previously described relatives. Here we examined the mechanism underlying the transmission of citrus tristeza virus (CTV) by its aphid vector,Toxoptera citricida, with the objective of identifying what virus-encoded proteins it uses to interact with the vector. Using fluorescently labeled virions, we demonstrated that CTV binds specifically to the lining of the cibarium of the aphid. Throughin vitrocompetitive binding assays between fluorescent virions and free viral proteins, we determined that the minor coat protein is involved in vector interaction. We also found that the presence of two heat shock-like proteins, p61 and p65, reduces virion bindingin vitro. Additionally, treating the dissected mouthparts with proteases did not affect the binding of CTV virions. In contrast, chitinase treatment reduced CTV binding to the foregut. Finally, competition with glucose,N-acetyl-β-d-glucosamine, chitobiose, and chitotriose reduced the binding. These findings together suggest that CTV binds to the sugar moieties of the cuticular surface of the aphid cibarium, and the binding involves the concerted activity of three virus-encoded proteins.IMPORTANCELimited information is known about the specific interactions between citrus tristeza virus and its aphid vectors. These interactions are important for the process of successful transmission. In this study, we localized the CTV retention site as the cibarium of the aphid foregut. Moreover, we demonstrated that the nature of these interactions is protein-carbohydrate binding. The viral proteins, including the minor coat protein and two heat shock proteins, bind to sugar moieties on the surface of the foregut. These findings will help in understanding the transmission mechanism of CTV by the aphid vector and may help in developing control strategies which interfere with the CTV binding to its insect vector to block the transmission.

scholarly journals Role of Defective RNAs in Citrus Tristeza Virus Diseases

2000 ◽  
Author(s):  
Moshe Bar-Joseph ◽  
William O. Dawson ◽  
Munir Mawassi
Keyword(s):  
Citrus Tristeza Virus ◽  
Genetic System ◽  
Helper Virus ◽  
Plant Viruses ◽  
Expression Vectors ◽  
The Us ◽  
Infected Cells ◽  
Tristeza Virus ◽  
Citrus Tristeza

This program focused on citrus tristeza virus (CTV), the largest and one of the most complex RNA-plant-viruses. The economic importance of this virus to the US and Israeli citrus industries, its uniqueness among RNA viruses and the possibility to tame the virus and eventually turn it into a useful tool for the protection and genetic improvement of citrus trees justify these continued efforts. Although the overall goal of this project was to study the role(s) of CTV associated defective (d)-RNAs in CTV-induced diseases, considerable research efforts had to be devoted to the engineering of the helper virus which provides the machinery to allow dRNA replication. Considerable progress was made through three main lines of complementary studies. For the first time, the generation of an engineered CTV genetic system that is capable of infecting citrus plants with in vitro modified virus was achieved. Considering that this RNA virus consists of a 20 kb genome, much larger than any other previously developed similar genetic system, completing this goal was an extremely difficult task that was accomplished by the effective collaboration and complementarity of both partners. Other full-length genomic CTV isolates were sequenced and populations examined, resulting in a new level of understanding of population complexities and dynamics in the US and Israel. In addition, this project has now considerably advanced our understanding and ability to manipulate dRNAs, a new class of genetic elements of closteroviruses, which were first found in the Israeli VT isolate and later shown to be omnipresent in CTV populations. We have characterized additional natural dRNAs and have shown that production of subgenomic mRNAs can be involved in the generation of dRNAs. We have molecularly cloned natural dRNAs and directly inoculated citrus plants with 35S-cDNA constructs and have shown that specific dRNAs are correlated with specific disease symptoms. Systems to examine dRNA replication in protoplasts were developed and the requirements for dRNA replication were defined. Several artificial dRNAs that replicate efficiently with a helper virus were created from infectious full-genomic cDNAs. Elements that allow the specific replication of dRNAs by heterologous helper viruses also were defined. The T36-derived dRNAs were replicated efficiently by a range of different wild CTV isolates and hybrid dRNAs with heterologous termini are efficiently replicated with T36 as helper. In addition we found: 1) All CTV genes except of the p6 gene product from the conserved signature block of the Closteroviridae are obligate for assembly, infectivity, and serial protoplast passage; 2) The p20 protein is a major component of the amorphous inclusion bodies of infected cells; and 3) Novel 5'-Co-terminal RNAs in CTV infected cells were characterized. These results have considerably advanced our basic understanding of the molecular biology of CTV and CTV-dRNAs and form the platform for the future manipulation of this complicated virus. As a result of these developments, the way is now open to turn constructs of this viral plant pathogen into new tools for protecting citrus against severe CTV terms and development of virus-based expression vectors for other citrus improvement needs. In conclusion, this research program has accomplished two main interconnected missions, the collection of basic information on the molecular and biological characteristics of the virus and its associated dRNAs toward development of management strategies against severe diseases caused by the virus and building of novel research tools to improve citrus varieties. Reaching these goals will allow us to advance this project to a new phase of turning the virus from a pathogen to an ally.

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