scholarly journals A Survey of Resistance to Tomato bushy stunt virus in the Genus Nicotiana Reveals That the Hypersensitive Response Is Triggered by One of Three Different Viral Proteins

2013 ◽  
Vol 26 (2) ◽  
pp. 240-248 ◽  
Author(s):  
Carlos A. Angel ◽  
James E. Schoelz
Keyword(s):  
Coat Protein ◽  
Hypersensitive Response ◽  
Rna Silencing ◽  
Mutational Analysis ◽  
Movement Protein ◽  
Viral Proteins ◽  
Tomato Bushy Stunt Virus ◽  
Necrosis Virus ◽  
Nicotiana Glutinosa ◽  
Cucumber Necrosis Virus

In this study, we screened 22 Nicotiana spp. for resistance to the tombusviruses Tomato bushy stunt virus (TBSV), Cucumber necrosis virus, and Cymbidium ringspot virus. Eighteen species were resistant, and resistance was manifested in at least two different categories. In all, 13 species responded with a hypersensitive response (HR)-type resistance, whereas another five were resistant but either had no visible response or responded with chlorotic lesions rather than necrotic lesions. Three different TBSV proteins were found to trigger HR in Nicotiana spp. in an agroinfiltration assay. The most common avirulence (avr) determinant was the TBSV coat protein P41, a protein that had not been previously recognized as an avr determinant. A mutational analysis confirmed that the coat protein rather than the viral RNA sequence was responsible for triggering HR, and it triggered HR in six species in the Alatae section. The TBSV P22 movement protein triggered HR in two species in section Undulatae (Nicotiana glutinosa and N. edwardsonii) and one species in section Alatae (N. forgetiana). The TBSV P19 RNA silencing suppressor protein triggered HR in sections Sylvestres (N. sylvestris), Nicotiana (N. tabacum), and Alatae (N. bonariensis). In general, Nicotiana spp. were capable of recognizing only one tombusvirus avirulence determinant, with the exceptions of N. bonariensis and N. forgetiana, which were each able to recognize P41, as well as P19 and P22, respectively. Agroinfiltration failed to detect the TBSV avr determinants responsible for triggering HR in N. arentsii, N. undulata, and N. rustica. This study illustrates the breadth and variety of resistance responses to tombusviruses that exists in the Nicotiana genus.

scholarly journals Mutational analysis of the cucumber necrosis virus coat protein gene

Virology ◽  
1995 ◽  
Vol 206 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Tim L. Sit ◽  
Julie C. Johnston ◽  
Melanie G. Ter Borg ◽  
Emile Frison ◽  
Morven A. McLean ◽  
...  
Keyword(s):  
Coat Protein ◽  
Coat Protein Gene ◽  
Protein Gene ◽  
Mutational Analysis ◽  
Necrosis Virus ◽  
Virus Coat Protein ◽  
Cucumber Necrosis Virus ◽  
Virus Coat

Involvement of the Cucumber Necrosis Virus Coat Protein in the Specificity of Fungus Transmission by Olpidium bornovanus

Virology ◽  
1994 ◽  
Vol 204 (2) ◽  
pp. 840-842 ◽  
Author(s):  
M.A. McLean ◽  
R.N. Campbell ◽  
R.I. Hamilton ◽  
D.M. Rochon
Keyword(s):  
Coat Protein ◽  
Necrosis Virus ◽  
Virus Coat Protein ◽  
Olpidium Bornovanus ◽  
Cucumber Necrosis Virus ◽  
Virus Coat

Cucumber necrosis virus p20 is a viral suppressor of RNA silencing

2011 ◽  
Vol 155 (2) ◽  
pp. 423-432 ◽  
Author(s):  
Xingan Hao ◽  
Amy Lu ◽  
Nadia Sokal ◽  
Basdeo Bhagwat ◽  
Earnest Leung ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Necrosis Virus ◽  
Viral Suppressor ◽  
Cucumber Necrosis Virus ◽  
Suppressor Of Rna Silencing

scholarly journals Induction of Particle Polymorphism by Cucumber Necrosis Virus Coat Protein Mutants In Vivo

2007 ◽  
Vol 82 (3) ◽  
pp. 1547-1557 ◽  
Author(s):  
Kishore Kakani ◽  
Ron Reade ◽  
Umesh Katpally ◽  
Thomas Smith ◽  
D'Ann Rochon
Keyword(s):  
Coat Protein ◽  
Rna Binding ◽  
In Planta ◽  
Necrosis Virus ◽  
Protein Mutants ◽  
Cucumber Necrosis Virus ◽  
Virus Coat ◽  
R Domain

ABSTRACT The Cucumber necrosis virus (CNV) particle is a T=3 icosahedron consisting of 180 identical coat protein (CP) subunits. Plants infected with wild-type CNV accumulate a high number of T=3 particles, but other particle forms have not been observed. Particle polymorphism in several T=3 icosahedral viruses has been observed in vitro following the removal of an extended N-terminal region of the CP subunit. In the case of CNV, we have recently described the structure of T=1 particles that accumulate in planta during infection by a CNV mutant (R1+2) in which a large portion of the N-terminal RNA binding domain (R-domain) has been deleted. In this report we further describe properties of this mutant and other CP mutants that produce polymorphic particles. The T=1 particles produced by R1+2 mutants were found to encapsidate a 1.9-kb RNA species as well as smaller RNA species that are similar to previously described CNV defective interfering RNAs. Other R-domain mutants were found to encapsidate a range of specifically sized less-than-full-length CNV RNAs. Mutation of a conserved proline residue in the arm domain near its junction with the shell domain also influenced T=1 particle formation. The proportion of polymorphic particles increased when the mutation was incorporated into R-domain deletion mutants. Our results suggest that both the R-domain and the arm play important roles in the formation of T=3 particles. In addition, the encapsidation of specific CNV RNA species by individual mutants indicates that the R-domain plays a role in the nature of CNV RNA encapsidated in particles.

scholarly journals Cucumber Necrosis Virus Recruits Cellular Heat Shock Protein 70 Homologs at Several Stages of Infection

2015 ◽  
Vol 90 (7) ◽  
pp. 3302-3317 ◽  
Author(s):  
Syed Benazir Alam ◽  
D'Ann Rochon
Keyword(s):  
Coat Protein ◽  
Heat Shock Protein 70 ◽  
Rna Replication ◽  
Multiple Roles ◽  
Viral Rna ◽  
Necrosis Virus ◽  
Chloroplast Targeting ◽  
Content Type ◽  
Hsp70 Family ◽  
Cucumber Necrosis Virus

ABSTRACTRNA viruses often depend on host factors for multiplication inside cells due to the constraints of their small genome size and limited coding capacity. One such factor that has been exploited by several plant and animal viruses is heat shock protein 70 (HSP70) family homologs which have been shown to play roles for different viruses in viral RNA replication, viral assembly, disassembly, and cell-to-cell movement. Using next generation sequence analysis, we reveal that several isoforms of Hsp70 and Hsc70 transcripts are induced to very high levels during cucumber necrosis virus (CNV) infection ofNicotiana benthamianaand that HSP70 proteins are also induced by at least 10-fold. We show that HSP70 family protein homologs are co-opted by CNV at several stages of infection. We have found that overexpression of Hsp70 or Hsc70 leads to enhanced CNV genomic RNA, coat protein (CP), and virion accumulation, whereas downregulation leads to a corresponding decrease. Hsc70-2 was found to increase solubility of CNV CPin vitroand to increase accumulation of CNV CP independently of viral RNA replication during coagroinfiltration inN. benthamiana. In addition, virus particle assembly into virus-like particles in CP agroinfiltrated plants was increased in the presence of Hsc70-2. HSP70 was found to increase the targeting of CNV CP to chloroplasts during infection, reinforcing the role of HSP70 in chloroplast targeting of host proteins. Hence, our findings have led to the discovery of a highly induced host factor that has been co-opted to play multiple roles during several stages of the CNV infection cycle.IMPORTANCEBecause of the small size of its RNA genome, CNV is dependent on interaction with host cellular components to successfully complete its multiplication cycle. We have found that CNV induces HSP70 family homologs to a high level during infection, possibly as a result of the host response to the high levels of CNV proteins that accumulate during infection. Moreover, we have found that CNV co-opts HSP70 family homologs to facilitate several aspects of the infection process such as viral RNA, coat protein and virus accumulation. Chloroplast targeting of the CNV CP is also facilitated, which may aid in CNV suppression of host defense responses. Several viruses have been shown to induce HSP70 during infection and others to utilize HSP70 for specific aspects of infection such as replication, assembly, and disassembly. We speculate that HSP70 may play multiple roles in the infection processes of many viruses.

Mutational analysis of the coat protein gene of tobacco mosaic virus in relation to hypersensitive response in tobacco plants with the N′ gene

Virology ◽  
1989 ◽  
Vol 173 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Tetsuichiro Saito ◽  
Kimiko Yamanaka ◽  
Yuichiro Watanabe ◽  
Nobuhiko Takamatsu ◽  
Tetsuo Meshi ◽  
...  
Keyword(s):  
Coat Protein ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Hypersensitive Response ◽  
Coat Protein Gene ◽  
Protein Gene ◽  
Mutational Analysis ◽  
N Gene ◽  
Tobacco Plants
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