scholarly journals Involvement of the chloroplast gene ferredoxin 1 in multiple responses of Nicotiana benthamiana to Potato virus X infection

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.

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.


Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1244-1244 ◽  
Author(s):  
S. Soler ◽  
C. López ◽  
F. Nuez

The Andean region is home of important genetic diversity for the genus Lycopersicon. A survey of three asymptomatic populations of L. hirsutum, 17 of L. parviflorum, 188 of L. pimpinellifolium, and four cultivated populations of L. esculentum was made in nine departments of Ecuador. Samples were analyzed serologically for Tomato spotted wilt virus (TSWV), Tomato mosaic virus (ToMV), Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Potato virus Y (PVY), Potato virus X (PVX), Groundnut ringspot virus (GRSV), Tomato chlorosis spot virus (TCSV), and Pepino mosaic virus (PepMV). Samples positive as determined using double-antibody sandwich enzyme-linked immunosorbent assay (absorbance values three times higher than negative controls) were analyzed using reverse transcription-polymerase chain reaction (RT-PCR) with virus-specific primers. L pimpinellifolium was the only species of the four found to be infected with viruses. In the department of Manabí, ToMV was detected in 15 of 16 plants from one population, but only a single plant was infected with PepMV. In this department, PepMV was also detected in a single-plant population that corresponded to a volunteer plant found in the wild and TSWV was detected in another plant. In Esmeraldas and Guayas, two single-plant populations were found infected with PepMV and CMV, respectively. TMV, PVY, PVX, GRSV, and TCSV were not detected in this survey. Specific primers were selected for ToMV (To1/To2, genome coordinates 3498-3518/4902-4922, AJ417701), PepMV (Pe1/Pe2 genome coordinates 5030-5050/5913-5935, AJ606359), CMV (Cm1/Cm2 genome coordinates 541-561/1756-1779, D00356), and TSWV (Ts1/Ts2 genome coordinates 4078-4101/4738-4769, AF208498). Amplicons of the expected size were obtained using RT-PCR and then cloned and sequenced. DNA fragments of ToMV, PepMV, and TSWV showed identities greater than 99% with respective sequences in the GenBank database. The highest identity of the CMV DNA fragment was 92% with an isolate from Indonesia (AB042292). The occurrence of viruses such as CMV, ToMV, and TSWV in coastal Ecuador was not surprising. However, infected plants were not found among the samples collected in the departments of Azuay, Carchí, El Oro, Imbabura, Loja, and Pichincha in eastern Ecuador. L. chilense, L. chmielewskii, L. parviflorum, and L. peruvianum were previously reported as natural hosts of PepMV in central and southern Peru (2), and the virus was also detected in L. esculentum in Chile (1). Our results show that PepMV now occurs in wild L. pimpinellifolium populations along the Pacific coast of the South American continent and that it must have efficient means of transmission, although no specific vectors have as yet been identified for this virus. To our knowledge, this is the first report of PepMV in Ecuador and L. pimpinellifolium as a natural host of PepMV. References: (1) M. Muñoz et al. Fitopatología 37:67, 2002. (2) S. Soler et al. J. Phytopathol. 150:49, 2002.


2008 ◽  
Vol 21 (12) ◽  
pp. 1539-1548 ◽  
Author(s):  
Phillip A. Harries ◽  
Karuppaiah Palanichelvam ◽  
Sumana Bhat ◽  
Richard S. Nelson

The Tobacco mosaic virus (TMV) 126-kDa protein is a suppressor of RNA silencing previously shown to delay the silencing of transgenes in Nicotiana tabacum and N. benthamiana. Here, we demonstrate that expression of a 126-kDa protein–green fluorescent protein (GFP) fusion (126-GFP) in N. tabacum increases susceptibility to a broad assortment of viruses, including Alfalfa mosaic virus, Brome mosaic virus, Tobacco rattle virus (TRV), and Potato virus X. Given its ability to enhance TRV infection in tobacco, we tested the effect of 126-GFP expression on TRV-mediated virus-induced gene silencing (VIGS) and demonstrate that this protein can enhance silencing phenotypes. To explain these results, we examined the poorly understood effect of suppressor dosage on the VIGS response and demonstrated that enhanced VIGS corresponds to the presence of low levels of suppressor protein. A mutant version of the 126-kDa protein, inhibited in its ability to suppress silencing, had a minimal effect on VIGS, suggesting that the suppressor activity of the 126-kDa protein is indeed responsible for the observed dosage effects. These findings illustrate the sensitivity of host plants to relatively small changes in suppressor dosage and have implications for those interested in enhancing silencing phenotypes in tobacco and other species through VIGS.


Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 730-740 ◽  
Author(s):  
Bright Agindotan ◽  
Keith L. Perry

A macroarray was developed for the detection of 11 potato viruses and Potato spindle tuber viroid. The 11 viruses detected included those commonly found or tested for in North American potato seed certification programs: Alfalfa mosaic virus, Cucumber mosaic virus, Potato mop top virus, Potato leafroll virus, Potato latent virus, Potato virus A, Potato virus M, Potato virus S, Potato virus X, Potato virus Y, and Tobacco rattle virus. These viruses were detected using oligonucleotide 70-mer probes and labeled targets prepared by a random primed amplification procedure. Potato plants analyzed included those infected with 12 reference virus stocks and 36 field isolates. Results from the macroarray were entirely consistent with those obtained using a standard serological assay (enzyme-linked immunosorbent assay). Four isolates of Potato spindle tuber viroid, in mixed infection with one or more viruses, also were detected in the array, although strong hybridization signals required amplification with viroid-specific primers in combination with anchored-random primers. In individual plants, up to four viruses, or a viroid plus two viruses, were detected, with no apparent competition or inhibition. Macroarrays are a cost-effective approach to the simultaneous diagnostic detection of multiple pathogens from infected plants.


2012 ◽  
Vol 93 (8) ◽  
pp. 1841-1850 ◽  
Author(s):  
Ida Bagus Andika ◽  
Hideki Kondo ◽  
Masamichi Nishiguchi ◽  
Tetsuo Tamada

Many plant viruses encode proteins that suppress RNA silencing, but little is known about the activity of silencing suppressors in roots. This study examined differences in the silencing suppression activity of different viruses in leaves and roots of Nicotiana benthamiana plants. Infection by tobacco mosaic virus, potato virus Y and cucumber mosaic virus but not potato virus X (PVX) resulted in strong silencing suppression activity of a transgene in both leaves and roots, whereas infection by beet necrotic yellow vein virus (BNYVV) and tobacco rattle virus (TRV) showed transgene silencing suppression in roots but not in leaves. For most viruses tested, viral negative-strand RNA accumulated at a very low level in roots, compared with considerable levels of positive-strand genomic RNA. Co-inoculation of leaves with PVX and either BNYVV or TRV produced an increase in PVX negative-strand RNA and subgenomic RNA (sgRNA) accumulation in roots. The cysteine-rich proteins (CRPs) BNYVV p14 and TRV 16K showed weak silencing suppression activity in leaves. However, when either of these CRPs was expressed from a PVX vector, there was an enhancement of PVX negative-strand RNA and sgRNA accumulation in roots compared with PVX alone. Such enhancement of PVX sgRNAs was also observed by expression of CRPs of other viruses and the well-known suppressors HC-Pro and p19 but not of the potato mop-top virus p8 CRP. These results indicate that BNYVV- and TRV-encoded CRPs suppress RNA silencing more efficiently in roots than in leaves.


2007 ◽  
Vol 88 (4) ◽  
pp. 1347-1355 ◽  
Author(s):  
Bong-Nam Chung ◽  
Tomas Canto ◽  
Peter Palukaitis

The stability of hybrid plant viruses that might arise by recombination in transgenic plants was examined using hybrid viruses derived from the viral expression vectors potato virus X (PVX) and tobacco rattle virus (TRV). The potato virus Y (PVY) NIb and HCPro open reading frames (ORFs) were introduced into PVX to generate PVX-NIb and PVX-HCPro, while the PVY NIb ORF was introduced into a vector derived from TRV RNA2 to generate TRV-NIb. All three viruses were unstable and most of the progeny viruses had lost the inserted sequences between 2 and 4 weeks post-inoculation. There was some variation in the rate of loss of part or all of the inserted sequence and the number of plants containing the deleted viruses, depending on the sequence, the host (Nicotiana tabacum vs Nicotiana benthamiana) or the vector, although none of these factors was associated consistently with the preferential loss of the inserted sequences. PVX-NIb was unable to accumulate in NIb-transgenic tobacco resistant to infection by PVY and also showed loss of the NIb insert from PVX-NIb in some NIb-transgenic tobacco plants susceptible to infection by PVY. These data indicate that such hybrid viruses, formed in resistant transgenic plants from a transgene and an unrelated virus, would be at a selective disadvantage, first by being targeted by the resistance mechanism and second by not being competitive with the parental virus.


Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 885
Author(s):  
Eva C. Thuenemann ◽  
Matthew J. Byrne ◽  
Hadrien Peyret ◽  
Keith Saunders ◽  
Roger Castells-Graells ◽  
...  

The production of plant helical virus-like particles (VLPs) via plant-based expression has been problematic with previous studies suggesting that an RNA scaffold may be necessary for their efficient production. To examine this, we compared the accumulation of VLPs from two potexviruses, papaya mosaic virus and alternanthera mosaic virus (AltMV), when the coat proteins were expressed from a replicating potato virus X- based vector (pEff) and a non-replicating vector (pEAQ-HT). Significantly greater quantities of VLPs could be purified when pEff was used. The pEff system was also very efficient at producing VLPs of helical viruses from different virus families. Examination of the RNA content of AltMV and tobacco mosaic virus VLPs produced from pEff revealed the presence of vector-derived RNA sequences, suggesting that the replicating RNA acts as a scaffold for VLP assembly. Cryo-EM analysis of the AltMV VLPs showed they had a structure very similar to that of authentic potexvirus particles. Thus, we conclude that vectors generating replicating forms of RNA, such as pEff, are very efficient for producing helical VLPs.


1998 ◽  
Vol 72 (1) ◽  
pp. 731-738 ◽  
Author(s):  
X. Ares ◽  
G. Calamante ◽  
S. Cabral ◽  
J. Lodge ◽  
P. Hemenway ◽  
...  

ABSTRACT The p24 protein, one of the three proteins implicated in local movement of potato virus X (PVX), was expressed in transgenic tobacco plants (Nicotiana tabacum Xanthi D8 NN). Plants with the highest level of p24 accumulation exhibited a stunted and slightly chlorotic phenotype. These transgenic plants facilitate the cell-to-cell movement of a mutant of PVX that contained a frameshift mutation in p24. Upon inoculation with tobacco mosaic virus (TMV), the size of necrotic local lesions was significantly smaller in p24+ plants than in nontransgenic, control plants. Systemic resistance to tobamoviruses was also evidenced after inoculation of p24+ plants with Ob, a virus that evades the hypersensitive response provided by the N gene. In the latter case, no systemic symptoms were observed, and virus accumulation remained low or undetectable by Western immunoblot analysis and back-inoculation assays. In contrast, no differences were observed in virus accumulation after inoculation with PVX, although more severe symptoms were evident on p24-expressing plants than on control plants. Similarly, infection assays conducted with potato virus Y showed no differences between control and transgenic plants. On the other hand, a considerable delay in virus accumulation and symptom development was observed when transgenic tobacco plants containing the movement protein (MP) of TMV were inoculated with PVX. Finally, a movement defective mutant of TMV was inoculated on p24+ plants or in mixed infections with PVX on nontransgenic plants. Both types of assays failed to produce TMV infections, implying that TMV MP is not interchangeable with the PVX MPs.


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