scholarly journals CRISPR/Cas9-mediated resistance to cauliflower mosaic virus

2017 ◽  
Author(s):  
Haijie Liu ◽  
Cara L. Soyars ◽  
Jianhui Li ◽  
Qili Fei ◽  
Guijuan He ◽  
...  

SummaryViral diseases are a leading cause of worldwide yield losses in crop production. Breeding of resistance genes (R gene) into elite crop cultivars has been the standard and most cost-effective practice. However, R gene-mediated resistance is limited by the available R genes within genetic resources and in many cases, by strain specificity. Therefore, it is important to generate new and broad-spectrum antiviral strategies. The CRISPR-Cas9 (clustered regularly interspaced palindromic repeat, CRISPR-associated) editing system has been employed to confer resistance to human viruses and several plant single-stranded DNA geminiviruses, pointing out the possible application of the CRISPR-Cas9 system for virus control. Here we demonstrate that strong viral resistance to cauliflower mosaic virus (CaMV), a pararetrovirus with a double-stranded DNA genome, can be achieved through Cas9-mediated multiplex targeting of the viral coat protein sequence. We further show that small interfering RNAs (siRNA) are produced and mostly map to the 3' end of guide RNAs (gRNA), although very low levels of siRNAs map to the spacer region as well. However, these siRNAs are not responsible for the inhibited CaMV infection because there is no resistance if Cas9 is not present. We have also observed edited viruses in systematically infected leaves in some transgenic plants, with short deletions or insertions consistent with Cas9-induced DNA breaks at the gRNA target sites in coat protein coding sequence. These edited coat proteins, in most cases, led to earlier translation stop and thus, non-functional coat proteins. We also recovered wild-type CP sequence in these infected transgenic plants, suggesting these edited viral genomes were packaged by wild-type coat proteins. Our data demonstrate that the CRISPR-Cas9 system can be used for virus control against plant pararetroviruses with further modifications.

2004 ◽  
Vol 17 (5) ◽  
pp. 475-483 ◽  
Author(s):  
Kappei Kobayashi ◽  
Thomas Hohn

Cauliflower mosaic virus (CaMV) transactivator/viroplasmin (Tav) is a multifunctional protein essential for basic replication of CaMV. It also plays a role in viral pathogenesis in crucifer and solanaceous host plants. Deletion mutagenesis revealed that N- and C-terminal parts of Tav are not essential for CaMV replication in transfected protoplasts. Two deletion mutants having only minimal defects in basic replication were infectious in turnips but only with highly attenuated virulence. This was shown to be due to delayed virus spread within the inoculated leaves and to the upper leaves. Unlike the wild-type virus, the mutant viruses successfully spread locally without inducing a host defense response in inoculated Datura stramonium leaves, but did not spread systemically. These results provide the first evidence that a Tav domain required for avirulence function in solanaceous plants is not essential for CaMV infectivity but has a role in viral virulence in susceptible hosts.


1999 ◽  
Vol 12 (5) ◽  
pp. 377-384 ◽  
Author(s):  
Chiara Geri ◽  
Edi Cecchini ◽  
Maria E. Giannakou ◽  
Simon N. Covey ◽  
Joel J. Milner

Cauliflower mosaic virus (CaMV) gene VI protein (P6) is an important determinant of symptom expression. Differential display polymerase chain reaction (PCR) was used to identify changes in gene expression in Arabidopsis elicited by a P6 transgene that causes a symptomatic phenotype. We used slot blot hybridization to measure the abundance of mRNAs complementary to 66 candidate PCR products in transgenic, CaMV-infected, and uninfected Arabidopsis plants. CaMV-infected and P6 transgenic plants showed broadly similar changes in abundance of mRNA species. In P6 transgenic plants we detected 18 PCR products that showed unambiguous changes in abundance plus another 15 that showed more limited changes (approximately twofold). CaMV-infected plants showed 17 unambiguous and 13 limited changes. Down-regulated species include those encoding a novel, phenol-like sulfotransferase, and a glycine-rich, RNA-binding protein. Up-regulated species included ones encoding an myb protein, glycine-rich and stress-inducible proteins, and a member of a previously unreported gene family. CaMV infection causes alterations in expression of many Arabidopsis genes. Transgene-mediated expression of P6 mimics virus infection in its effect on host gene expression, providing a potential mechanism for this process.


2019 ◽  
Vol 71 (6) ◽  
pp. 2142-2156 ◽  
Author(s):  
Xue Yang ◽  
Yuwen Lu ◽  
Fang Wang ◽  
Ying Chen ◽  
Yanzhen Tian ◽  
...  

Abstract The chloroplast protein ferredoxin 1 (FD1), with roles in the chloroplast electron transport chain, is known to interact with the coat proteins (CPs) of Tomato mosaic virus and Cucumber mosaic virus. However, our understanding of the roles of FD1 in virus infection remains limited. Here, we report that the Potato virus X (PVX) p25 protein interacts with FD1, whose mRNA and protein levels are reduced by PVX infection or by transient expression of p25. Silencing of FD1 by Tobacco rattle virus-based virus-induced gene silencing (VIGS) promoted the local and systemic infection of plants by PVX. Use of a drop-and-see (DANS) assay and callose staining revealed that the permeability of plasmodesmata (PDs) was increased in FD1-silenced plants together with a consistently reduced level of PD callose deposition. After FD1 silencing, quantitative reverse transcription–real-time PCR (qRT–PCR) analysis and LC-MS revealed these plants to have a low accumulation of the phytohormones abscisic acid (ABA) and salicylic acid (SA), which contributed to the decreased callose deposition at PDs. Overexpression of FD1 in transgenic plants manifested resistance to PVX infection, but the contents of ABA and SA, and the PD callose deposition were not increased in transgenic plants. Overexpression of FD1 interfered with the RNA silencing suppressor function of p25. These results demonstrate that interfering with FD1 function causes abnormal plant hormone-mediated antiviral processes and thus enhances PVX infection.


Microbiology ◽  
2000 ◽  
Vol 81 (7) ◽  
pp. 1851-1855 ◽  
Author(s):  
Carole L. Thomas ◽  
Andrew J. Maule

To investigate the process of tubule formation for the cauliflower mosaic virus movement protein (CaMV MP), the green fluorescent protein (GFP) was fused to the MP to provide a vital marker for MP location after expression in insect cells. In contrast to the long tubular structures seen previously following baculovirus-based expression of the wild-type MP, the fusion protein produced only aggregates of fluorescing material in the cytoplasm. However, by co-expressing wild-type MP and GFP–MP, or by engineering their co-accumulation by introducing a foot-and-mouth disease virus 2A cleavage sequence between GFP and MP, long GFP-fluorescing tubules were formed. The experiments suggest that the presence of GFP at the N or C terminus of the tubule-forming domain of the CaMV MP places steric constraints upon the aggregation of the MP into a tubule but that this can be overcome by providing wild-type protein for inclusion in the aggregate.


2003 ◽  
Vol 77 (17) ◽  
pp. 9211-9220 ◽  
Author(s):  
Sophia Biemelt ◽  
Uwe Sonnewald ◽  
Petra Galmbacher ◽  
Lothar Willmitzer ◽  
Martin Müller

ABSTRACT Cervical cancer is linked to infection with human papillomaviruses (HPV) and is the third most common cancer among women worldwide. There is a strong demand for the development of an HPV preventive vaccine. Transgenic plants expressing the HPV major capsid protein L1 could be a system to produce virus-like particles for prophylactic vaccination or could even be used as edible vaccines to induce an L1-specific prophylactic immune response. Here, we describe the generation of transgenic tobacco and potato plants carrying the HPV type 16 major structural gene L1 under the control of the cauliflower mosaic virus 35S promoter. All attempts to express either the original, unmodified L1 gene or an L1 gene with a codon usage optimized for expression in plants failed. Surprisingly, small amounts of the protein were detected using an L1 gene optimized for expression in human cells. However, Northern blot analysis revealed that most of the L1 transcripts were degraded. Introduction of the translational enhancer Ω derived from the tobacco mosaic virus strongly increased transcript stability and resulted in accumulation of L1 protein to approximately 0.5 to 0.2% of total soluble protein in transgenic tobacco and potato plants, respectively. The plant-derived L1 protein displayed conformation-specific epitopes and assembled into virus-like particles. Furthermore, we did not find any indications of protein modification of the L1 protein produced in plants. Plant-derived L1 was as immunogenic as L1 expressed in baculovirus-infected insect cells. Feeding of tubers from transgenic potatoes to mice induced an anti-L1 antibody response in 3 out of 24 mice, although this response was only transient in two of the mice. Our data, however, indicate that an anti-L1 response was primed in about half of the 24 animals.


1999 ◽  
Vol 12 (2) ◽  
pp. 153-162 ◽  
Author(s):  
Marise Borja ◽  
Teresa Rubio ◽  
Herman B. Scholthof ◽  
Andrew O. Jackson

Nicotiana benthamiana plants transformed with the coat protein gene of tomato bushy stunt virus (TBSV) failed to elicit effective virus resistance when inoculated with wild-type virus. Subsequently, R1 and R2 progeny from 13 transgenic lines were inoculated with a TBSV mutant containing a defective coat protein gene. Mild symptoms typical of those elicited in nontransformed plants infected with the TBSV mutant initially appeared. However, within 2 to 4 weeks, up to 20% of the transgenic plants sporadically began to develop the lethal syndrome characteristic of wild-type virus infections. RNA hybridization and immunoblot analyses of these plants and nontransformed N. benthamiana inoculated with virus from the transgenic lines indicated that wild-type virus had been regenerated by a double recombination event between the defective virus and the coat protein transgene. Similar results were obtained with a TBSV deletion mutant containing a nucleotide sequence marker, and with a chimeric cucumber necrosis virus (CNV) containing the defective TBSV coat protein gene. In both cases, purified virions contained wild-type TBSV RNA or CNV chimeric RNA derived by recombination with the transgenic coat protein mRNA. These results thus demonstrate that recombinant tombusviruses can arise frequently from viral genes expressed in transgenic plants.


2006 ◽  
Vol 87 (4) ◽  
pp. 1005-1012 ◽  
Author(s):  
A. A. Bazzini ◽  
S. Asurmendi ◽  
H. E. Hopp ◽  
R. N. Beachy

Replication of Potato virus X (PVX) was reduced in transgenic protoplasts that accumulated wild-type coat protein (CPWT) of Tobacco mosaic virus (TMV) or a mutant CP, CPT42W, that produced highly ordered states of aggregation, including pseudovirions. This reaction is referred to as heterologous CP-mediated resistance. However, protoplasts expressing a CP mutant that abolished aggregation and did not produce pseudovirions, CPT28W, did not reduce PVX replication. Similarly, in transgenic tobacco plants producing TMV CPWT or CPT42W, there was a delay in local cell-to-cell spread of PVX infection that was not observed in CPT28W plants or in non-transgenic plants. The results suggest that the quaternary structure of the TMV CP regulates the mechanism(s) of heterologous CP-mediated resistance. Similarly, transgenic protoplasts that produced PVX CP conferred transient protection against infection by TMV RNA. Transgenic plants that accumulated PVX CP reduced the cell-to-cell spread of infection and resulted in a delay in systemic infection following inoculation with TMV or TMV RNA. Heterologous CP-mediated resistance was characterized by a brief delay in systemic infection, whilst homologous CP-mediated resistance conferred reduced or no systemic infection.


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