Development and Optimization of Tobacco necrosis virus A Induced Gene Silencing in Nicotiana benthamiana*

2011 ◽  
Vol 38 (10) ◽  
pp. 919-928 ◽  
Author(s):  
Yang GAO ◽  
Yong-Liang ZHANG ◽  
Xiao-Feng ZHANG ◽  
Cheng-Gui HAN ◽  
Jia-Lin YU ◽  
...  
2020 ◽  
pp. MPMI-07-20-0184
Author(s):  
Zongyu Gao ◽  
Heng Pu ◽  
Jingyuan Liu ◽  
Xiaoling Wang ◽  
Chenchen Zhong ◽  
...  

Plant viruses often infect several distinct host species. Sometimes, viruses can systemically infect a specific host whereas, in other cases, only local infections occur in other species. How viral and host factors interact to determine systemic infections among different hosts is largely unknown, particularly for icosahedral positive-stranded RNA viruses. The Tobacco necrosis virus-A Chinese isolate belongs to the genus Alphanecrovirus in the family Tombusviridae. In this study, we investigated variations in systemic infections of tobacco necrosis virus-AC (TNV-AC) in Nicotiana benthamiana and Glycine max (soybean) by alanine-scanning mutagenesis of the viral coat protein (CP), which is essential for systemic movement of TNV-AC. We found that three amino acids, R169, K177, and Q233, are key residues that mediate varying degrees of systemic infections of N. benthamiana and soybean. Further analysis revealed that variations in systemic trafficking of TNV-AC CP mutants in N. benthamiana and soybean are associated with virion assembly and stability. The CP amino acids K177 and Q233 are highly conserved among all TNV-A isolates and are replaced by Q and K in the TNV-D isolates. We demonstrated that systemic infectivity of either TNV-AC K177A and Q233A or K177Q and Q233K mutants are correlated with the binding affinity of the mutated CPs to the host-specific Hsc70-2 protein. These results expand our understanding of host-dependent long-distance movement of icosahedral viruses in plants. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .


1999 ◽  
Vol 23 (3) ◽  
pp. 174-175
Author(s):  
E. Abdel-Ghani

The orientation of cyclization of the reaction of methyl aroylacrylate (1) and aroylacrylic acid (8) with ethyl acetoacetate and/or thiourea leading to the formation of 4-aroylmethylcyclopentane-1,3-dione (2) 5-aryl-3-oxocyclohexene-1,2-dicarboxylic acid (9), 2-imino-5-aroylmethylthiazolidin-4-one (11) and 6-aryl-2-sulfonylpyrimidine-4-carboxylic acid (14) depends on the medium employed; some compounds show moderate antiviral activities against tobacco necrosis virus.


2012 ◽  
Vol 39 (9) ◽  
pp. 764 ◽  
Author(s):  
Gi-Ho Lee ◽  
Seong-Han Sohn ◽  
Eun-Young Park ◽  
Young-Doo Park

The chemical modification of DNA by methylation is a heritable trait and can be subsequently reversed without altering the original DNA sequence. Methylation can reduce or silence gene expression and is a component of a host’s defence response to foreign nucleic acids. In our study, we employed a plant transformation strategy using Nicotiana benthamiana Domin to study the heritable stability of the introduced transgenes. Through the introduction of the cauliflower mosaic virus (CaMV) 35S promoter and the green fluorescent protein (GFP) reporter gene, we demonstrated that this introduced promoter often triggers a homology-dependent gene-silencing (HDGS) response. These spontaneous transgene-silencing phenomena are due to methylation of the CaMV 35S promoter CAAT box during transgenic plant growth. This process is catalysed by SU(VAR)3–9 homologue 9 (SUVH9), histone deacetylase 1 (HDA1) and domains rearranged methylase 2 (DRM2). In particular, we showed from our data that SUVH9 is the key regulator of methylation activity in epigenetically silenced GFP transgenic lines; therefore, our findings demonstrate that an introduced viral promoter and transgene can be subject to a homology-dependent gene-silencing mechanism that can downregulate its expression and negatively influence the heritable stability of the transgene.


1993 ◽  
Vol 13 (6) ◽  
pp. 3340-3349 ◽  
Author(s):  
X Danthinne ◽  
J Seurinck ◽  
F Meulewaeter ◽  
M Van Montagu ◽  
M Cornelissen

The RNA of satellite tobacco necrosis virus (STNV) is a monocistronic messenger that lacks both a 5' cap structure and a 3' poly(A) tail. We show that in a cell-free translation system derived from wheat germ, STNV RNA lacking the 600-nucleotide trailer is translated an order of magnitude less efficiently than full-size RNA. Deletion analyses positioned the translational enhancer domain (TED) within a conserved hairpin structure immediately downstream from the coat protein cistron. TED enhances translation when fused to a heterologous mRNA, but the level of enhancement depends on the nature of the 5' untranslated sequence and is maximal in combination with the STNV leader. The STNV leader and TED have two regions of complementarity. One of the complementary regions in TED resembles picornavirus box A, which is involved in cap-independent translation but which is located upstream of the coding region.


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