Host-Dependent Requirement for the Potato leafroll virus 17-kDa Protein in Virus Movement

The requirement for the 17-kDa protein (P17) of Potato leafroll virus (PLRV) in virus movement was investigated in four plant species: potato (Solanum tuberosum), Physalis floridana, Nicotiana benthamiana, and N. clevelandii. Two PLRV P17 mutants were characterized, one that does not translate the P17 and another that expresses a P17 missing the first four amino acids. The P17 mutants were able to replicate and accumulate in agroinoculated leaves of potato and P. floridana, but they were unable to move into vascular tissues and initiate a systemic infection in these plants. In contrast, the P17 mutants were able to spread systemically from inoculated leaves in both Nicotiana spp., although the efficiency of infection was reduced relative to wild-type PLRV. Examination of virus distribution in N. benthamiana plants using tissue immunoblotting techniques revealed that the wild-type PLRV and P17 mutants followed a similar movement pathway out of the inoculated leaves. Virus first moved upward to the apical tissues and then downward. The P17 mutants, however, infected fewer phloem-associated cells, were slower than wild-type PLRV in moving out of the inoculated tissue and into apical tissues, and were unable to infect any mature leaves present on the plant at the time of inoculation.

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A Surface Loop of the Potato Leafroll Virus Coat Protein Is Involved in Virion Assembly, Systemic Movement, and Aphid Transmission

Journal of Virology ◽

10.1128/jvi.79.2.1207-1214.2005 ◽

2005 ◽

Vol 79 (2) ◽

pp. 1207-1214 ◽

Cited By ~ 44

Author(s):

Lawrence Lee ◽

Igor B. Kaplan ◽

Daniel R. Ripoll ◽

Delin Liang ◽

Peter Palukaitis ◽

...

Keyword(s):

Amino Acids ◽

Coat Protein ◽

Virus Assembly ◽

Systemic Infection ◽

Aphid Transmission ◽

Potato Leafroll Virus ◽

Wild Type Virus ◽

Virion Assembly ◽

Aphid Vectors ◽

Leafroll Virus

ABSTRACT Two acidic domains of the Potato leafroll virus (PLRV) coat protein, separated by 55 amino acids and predicted to be adjacent surface features on the virion, were the focus of a mutational analysis. Eleven site-directed mutants were generated from a cloned infectious cDNA of PLRV and delivered to plants by Agrobacterium-mediated mechanical inoculation. Alanine substitutions of any of the three amino acids of the sequence EWH (amino acids 170 to 172) or of D177 disrupted the ability of the coat protein to assemble stable particles and the ability of the viral RNA to move systemically in four host plant species. Alanine substitution of E109, D173, or E176 reduced the accumulation of virus in agrobacterium-infiltrated tissues, the efficiency of systemic infection, and the efficiency of aphid transmission relative to wild-type virus, but the mutations did not affect virion stability. A structural model of the PLRV capsid predicted that the amino acids critical for virion assembly were located within a depression at the center of a coat protein trimer. The other amino acids that affected plant infection and/or aphid transmission were predicted to be located around the perimeter of the depression. PLRV virions play key roles in phloem-limited virus movement in plant hosts as well as in transport and persistence in the aphid vectors. These results identified amino acid residues in a surface-oriented loop of the coat protein that are critical for virus assembly and stability, systemic infection of plants, and movement of virus through aphid vectors.

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Expression Level of Mature miR172 in Wild Type and StSUT4-Silenced Plants of Solanum tuberosum Is Sucrose-Dependent

International Journal of Molecular Sciences ◽

10.3390/ijms22031455 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1455

Author(s):

Varsha Garg ◽

Aleksandra Hackel ◽

Christina Kühn

Keyword(s):

Solanum Tuberosum ◽

Wild Type ◽

Potato Plants ◽

Mature Leaves ◽

In Vitro Plantlets ◽

Long Time ◽

Short Time ◽

Cut Leaves

In potato plants, the phloem-mobile miR172 is involved in the sugar-dependent transmission of flower and tuber inducing signal transduction pathways and a clear link between solute transport and the induction of flowering and tuberization was demonstrated. The sucrose transporter StSUT4 seems to play an important role in the photoperiod-dependent triggering of both developmental processes, flowering and tuberization, and the phenotype of StSUT4-inhibited potato plants is reminiscent to miR172 overexpressing plants. The first aim of this study was the determination of the level of miR172 in sink and source leaves of StSUT4-silenced as well as StSUT4-overexpressing plants in comparison to Solanum tuberosum ssp. Andigena wild type plants. The second aim was to investigate the effect of sugars on the level of miRNA172 in whole cut leaves, as well as in whole in vitro plantlets that were supplemented with exogenous sugars. Experiments clearly show a sucrose-dependent induction of the level of mature miR172 in short time as well as long time experiments. A sucrose-dependent accumulation of miR172 was also measured in mature leaves of StSUT4-silenced plants where sucrose export is delayed and sucrose accumulates at the end of the light period.

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The Three Essential Motifs in P0 for Suppression of RNA Silencing Activity of Potato leafroll virus Are Required for Virus Systemic Infection

Viruses ◽

10.3390/v11020170 ◽

2019 ◽

Vol 11 (2) ◽

pp. 170 ◽

Cited By ~ 5

Author(s):

Mamun-Or Rashid ◽

Xiao-Yan Zhang ◽

Ying Wang ◽

Da-Wei Li ◽

Jia-Lin Yu ◽

...

Keyword(s):

Amino Acid ◽

Gene Silencing ◽

Rna Silencing ◽

Systemic Infection ◽

Rna Degradation ◽

Potato Leafroll Virus ◽

Posttranscriptional Gene Silencing ◽

Conserved Region ◽

Leafroll Virus ◽

The Impact

Higher plants exploit posttranscriptional gene silencing as a defense mechanism against virus infection by the RNA degradation system. Plant RNA viruses suppress posttranscriptional gene silencing using their encoded proteins. Three important motifs (F-box-like motif, G139/W140/G141-like motif, and C-terminal conserved region) in P0 of Potato leafroll virus (PLRV) were reported to be essential for suppression of RNA silencing activity. In this study, Agrobacterium-mediated transient experiments were carried out to screen the available amino acid substitutions in the F-box-like motif and G139/W140/G141-like motif that abolished the RNA silencing suppression activity of P0, without disturbing the P1 amino acid sequence. Subsequently, four P0 defective mutants derived from a full-length cDNA clone of PLRV (L76F and W87R substitutions in the F-box-like motif, G139RRR substitution in the G139/W140/G141-like motif, and F220R substitution in the C-terminal conserved region) were successfully generated by reverse PCR and used to investigate the impact of these substitutions on PLRV infectivity. The RT-PCR and western blot analysis revealed that these defective mutants affected virus accumulation in inoculated leaves and systemic movement in Nicotiana benthamiana as well as in its natural hosts, potato and black nightshade. These results further demonstrate that the RNA silencing suppressor of PLRV is required for PLRV accumulation and systemic infection.

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Temperature and CO2 Level Influence Potato leafroll virus Infection in Solanum tuberosum

The Plant Pathology Journal ◽

10.5423/ppj.nt.01.2017.0019 ◽

2017 ◽

Vol 33 (5) ◽

pp. 522-527 ◽

Cited By ~ 3

Author(s):

Bong Nam Chung ◽

Sang Wook Koh ◽

Kyung San Choi ◽

Jae Ho Joa ◽

Chun Hwan Kim ◽

...

Keyword(s):

Solanum Tuberosum ◽

Virus Infection ◽

Potato Leafroll Virus ◽

Co2 Level ◽

Leafroll Virus

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Introgression of the Rl adg allele of resistance to potato leafroll virus in Solanum tuberosum L.

Cropp Breeding and Applied Biotechnology ◽

10.1590/1984-70332017v17n3a37 ◽

2017 ◽

Vol 17 (3) ◽

pp. 242-249 ◽

Cited By ~ 1

Author(s):

Otávio Luiz Gomes Carneiro ◽

Silvia Regina Rodrigues de Paula Ribeiro ◽

Carolina Mariane Moreira ◽

Marcio Lisboa Guedes ◽

Danilo Hottis Lyra ◽

...

Keyword(s):

Solanum Tuberosum ◽

Solanum Tuberosum L ◽

Potato Leafroll Virus ◽

Leafroll Virus

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High Levels of Heritable Resistance to Potato Leafroll Virus (PLRV) in Solanum tuberosum subsp. andigena

Crop Science ◽

10.2135/cropsci2006.06.0369 ◽

2007 ◽

Vol 47 (3) ◽

pp. 1091-1103 ◽

Cited By ~ 7

Author(s):

E. Mihovilovich ◽

L. Alarcón ◽

A. L. Pérez ◽

J. Alvarado ◽

C. Arellano ◽

...

Keyword(s):

Solanum Tuberosum ◽

Potato Leafroll Virus ◽

Leafroll Virus

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Components of Arabidopsis Defense- and Ethylene-Signaling Pathways Regulate Susceptibility to Cauliflower mosaic virus by Restricting Long-Distance Movement

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-6-0659 ◽

2007 ◽

Vol 20 (6) ◽

pp. 659-670 ◽

Cited By ~ 52

Author(s):

Andrew J. Love ◽

Valérie Laval ◽

Chiara Geri ◽

Janet Laird ◽

A. Deri Tomos ◽

...

Keyword(s):

Mosaic Virus ◽

Systemic Acquired Resistance ◽

Fluorescent Protein ◽

Acquired Resistance ◽

Systemic Infection ◽

Cauliflower Mosaic Virus ◽

Virus Movement ◽

Wild Type ◽

Long Distance ◽

Systemic Spread

We analyzed the susceptibility of Arabidopsis mutants with defects in salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) signaling to infection by Cauliflower mosaic virus (CaMV). Mutants cpr1-1 and cpr5-2, in which SA-dependent defense signaling is activated constitutively, were substantially more resistant than the wild type to systemic infection, implicating SA signaling in defense against CaMV. However, SA-deficient NahG, sid2-2, eds5-1, and pad4-1 did not show enhanced susceptibility. A cpr5 eds5 double mutant also was resistant, suggesting that resistance in cpr5 may function partially independently of SA. Treatment of cpr5 and cpr5 eds5, but not cpr1, with salicyl-hydroxamic acid, an inhibitor of alternative oxidase, partially restored susceptibility to wild-type levels. Mutants etr1-1, etr1-3, and ein2-1, and two mutants with lesions in ET/JA-mediated defense, eds4 and eds8, also showed reduced virus susceptibility, demonstrating that ET-dependent responses also play a role in susceptibility. We used a green fluorescent protein (GFP)-expressing CaMV recombinant to monitor virus movement. In mutants with reduced susceptibility, cpr1-1, cpr5-2, and etr1-1, CaMV-GFP formed local lesions similar to the wild type, but systemic spread was almost completely absent in cpr1 and cpr5 and was substantially reduced in etr1-1. Thus, mutations with enhanced systemic acquired resistance or compromised ET signaling show diminished long-distance virus movement.

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