scholarly journals Co-inoculation with two non-infectious cDNA copies of potato spindle tuber viroid (PSTVd) leads to the appearance of novel fully infectious variants.

2005 ◽  
Vol 52 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Wojciech Podstolski ◽  
Anna Góra-Sochacka ◽  
Włodzimierz Zagórski
Keyword(s):  
Cell Movement ◽  
Systemic Infection ◽  
Potato Spindle Tuber Viroid ◽  
Disease Symptoms ◽  
Non Coding Rna ◽  
Infectious Clones ◽  
Novel Variants ◽  
Test Plants

Potato spindle tuber viroid (PSTVd) is one of the smallest (about 360 nt) infectious plant agents. It is composed of a single-stranded circular non-coding RNA molecule. In the course of previous passage experiments with two intermediate PSTVd variants I2 and I4, three non-infectious clones (I2-50, I4-37 and I4 VI-17) were found. When inoculated separately as cDNAs on tomato "Rutgers" test plants these variants did not induce any visible disease symptoms and did not produce progeny. The presence of such non-infectious variants raises several questions about their origin and biology and to answer them, mixed co-infections with cDNA copies of two non-infectious variants (I2-50, I4-37) were performed. PSTVd infection was observed in seven out of 30 inoculated plants. The progeny isolated from three separate plants contained novel variants, together with the parental I2 and I4 sequences. It is conceivable that the appearance of repaired PSTVd molecules, clearly capable of cell-to-cell movement leading to the systemic infection, results from recombination events. An analysis of the recombinant molecules and comparison with databases identified the specific sites responsible for the restricted infectivity of the I2-50 and I4-37 PSTVd variants. In parallel experiments in which (+) strand PSTVd infectious transcripts were used, no recombinants were observed, and the original I2-50 and I4-37 non-infectious sequences were not detected in the progeny.

scholarly journals Potato spindle tuber viroid

2021 ◽  
Vol 25 (3) ◽  
pp. 269-275
Author(s):  
A. V. Kochetov ◽  
A. Y. Pronozin ◽  
N. V. Shatskaya ◽  
D. A. Afonnikov ◽  
O. S. Afanasenko
Keyword(s):  
Host Plants ◽  
Infected Plant ◽  
Systemic Infection ◽  
Potato Spindle Tuber Viroid ◽  
Pathological Effect ◽  
Genomic Rnas ◽  
Disease Symptoms ◽  
Cellular Mrnas ◽  
Interesting Class ◽  
Acid Pathway

Viroids belong to a very interesting class of molecules attracting researchers in phytopathology and molecular evolution. Here we review recent literature data concerning the genetics of Potato spindle tuber viroid (PSTVd) and the mechanisms related to its pathological effect on the host plants. PSTVd can be transmitted vertically through microspores and macrospores, but not with pollen from another infected plant. The 359 nucleotidelong genomic RNA of PSTVd is highly structured and its 3D-conformation is responsible for interaction with host cellular factors to mediate replication, transport between tissues during systemic infection and the severity of pathological symptoms. RNA replication is prone to errors and infected plants contain a population of mutated forms of the PSTVd genome. Interestingly, at 7 DAI, only 25 % of the newly synthesized RNAs were identical to the master copy, but this proportion increased to up to 70 % at 14 DAI and remained the same afterwards. PSTVd infection induces the immune response in host plants. There are PSTVd strains with a severe, a moderate or a mild pathological effect. Interestingly, viroid replication itself does not necessarily induce strong morphological or physiological symptoms. In the case of PSTVd, disease symptoms may occur due to RNA-interference, which decreases the expression levels of some important cellular regulatory factors, such as, for example, potato StTCP23 from the gibberellic acid pathway with a role in tuber morphogenesis or tomato FRIGIDA-like protein 3 with an early flowering phenotype. This association between the small segments of viroid genomic RNAs complementary to the untranslated regions of cellular mRNAs and disease symptoms provides a way for new resistant cultivars to be developed by genetic editing. To conclude, viroids provide a unique model to reveal the fundamental features of living systems, which appeared early in evolution and still remain undiscovered.

scholarly journals Multiple aromatic amino acids are involved in potyvirus movement by forming π-stackings to maintain coat protein accumulation

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Zhi-Yong Yan ◽  
Xiao-Jie Xu ◽  
Le Fang ◽  
Chao Geng ◽  
Yan-Ping Tian ◽  
...  
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Infectious Clone ◽  
Three Dimensional ◽  
Cell Movement ◽  
Systemic Infection ◽  
Watermelon Mosaic Virus ◽  
Protein Accumulation ◽  
Three Dimensional Model ◽  
Aromatic Residues

AbstractCoat protein (CP) is required for potyviruses to move and establish a systemic infection in plants. π-stackings formed by aromatic residues play critical roles in maintaining protein stability and functions. As we know, many aromatic residues located in the core region of potyvirus CPs are conserved. However, their roles in potyvirus infection remain largely unknown. Here, through analysis of the three-dimensional model of the tobacco vein banding mosaic virus (TVBMV; genus Potyvirus) CP, 16 aromatic residues were predicated to form π-stackings. The results of transient expression experiments demonstrated that deletion of any of these 16 aromatic residues reduced CP accumulation. Infectivity assays showed that deletion of any of these aromatic residues in the TVBMV infectious clone abolished cell-to-cell movement and reduced replication of the virus. Substitution of Y105 and Y147 individually with non-aromatic residues alanine or glycine reduced CP accumulation, virus replication, and abolished the ability of TVBMV to move intercellularly, while substitution of these two residues individually with aromatic residues phenylalanine or tryptophan, had no or little effect on CP accumulation and TVBMV systemic movement and replication. Similar results were obtained from the CP mutants of watermelon mosaic virus (WMV, genus Potyvirus). Taken together, our results demonstrate that multiple aromatic residues in CP are involved in potyvirus movement by forming π-stackings to maintain CP accumulation.

scholarly journals Distribution of Potato spindle tuber viroid in Reproductive Organs of Petunia During Its Developmental Stages

2014 ◽  
Vol 104 (9) ◽  
pp. 964-969 ◽  
Author(s):  
Yosuke Matsushita ◽  
Shinya Tsuda
Keyword(s):  
Developmental Stages ◽  
Cell Movement ◽  
Seed Transmission ◽  
Potato Spindle Tuber Viroid ◽  
Reproductive Organs ◽  
Infected Male ◽  
Infected Female ◽  
Reproductive Tissues ◽  
Healthy Female

Embryo infection is important for efficient seed transmission of viroids. To identify the major pattern of seed transmission of viroids, we used in situ hybridization to histochemically analyze the distribution of Potato spindle tuber viroid (PSTVd) in each developmental stage of petunia (flowering to mature seed stages). In floral organs, PSTVd was present in the reproductive tissues of infected female × infected male and infected female × healthy male but not of healthy female × infected male before embryogenesis. After pollination, PSTVd was detected in the developed embryo and endosperm in all three crosses. These findings indicate that PSTVd is indirectly delivered to the embryo through ovule or pollen during the development of reproductive tissues before embryogenesis but not directly through maternal tissues as cell-to-cell movement during embryogenesis.

scholarly journals Tomato Twisted Leaf Virus: A Novel Indigenous New World Monopartite Begomovirus Infecting Tomato in Venezuela

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 327 ◽  
Author(s):  
Gustavo Romay ◽  
Francis Geraud-Pouey ◽  
Dorys Chirinos ◽  
Mathieu Mahillon ◽  
Annika Gillis ◽  
...  
Keyword(s):  
Crop Production ◽  
New World ◽  
Systemic Infection ◽  
Plant Viruses ◽  
Monopartite Begomoviruses ◽  
Bipartite Begomoviruses ◽  
Reading Frame ◽  
Reverse Transcription Pcr ◽  
Infectious Clones ◽  
Leaf Virus

Begomoviruses are one of the major groups of plant viruses with an important economic impact on crop production in tropical and subtropical regions. The global spread of its polyphagous vector, the whitefly Bemisia tabaci, has contributed to the emergence and diversification of species within this genus. In this study, we found a putative novel begomovirus infecting tomato plants in Venezuela without a cognate DNA-B component. This begomovirus was genetically characterized and compared with related species. Furthermore, its infectivity was demonstrated by agroinoculation of infectious clones in tomato (Solanum lycopersicum) and Nicotiana benthamiana plants. The name Tomato twisted leaf virus (ToTLV) is proposed. ToTLV showed the typical genome organization of the DNA-A component of New World bipartite begomoviruses. However, the single DNA component of ToTLV was able to develop systemic infection in tomato and N. benthamiana plants, suggesting a monopartite nature of its genome. Interestingly, an additional open reading frame ORF was observed in ToTLV encompassing the intergenic region and the coat protein gene, which is not present in other closely related begomoviruses. A putative transcript from this region was amplified by strand-specific reverse transcription-PCR. Along with recent studies, our results showed that the diversity of monopartite begomoviruses from the New World is greater than previously thought.

scholarly journals Wheat dwarf virus infectious clones allow to infect wheat and Triticum monococcum plants

2019 ◽  
Vol 55 (No. 2) ◽  
pp. 81-89 ◽  
Author(s):  
Pavel Cejnar ◽  
Ludmila Ohnoutková ◽  
Jan Ripl ◽  
Jiban Kumar Kundu
Keyword(s):  
Systemic Infection ◽  
Triticum Monococcum ◽  
Dwarf Virus ◽  
Gene Gun ◽  
Wheat Dwarf Virus ◽  
Inoculation Method ◽  
Infectious Clones ◽  
Bacterial Plasmid ◽  
Biolistic Inoculation ◽  
Das Elisa

We constructed Wheat dwarf virus (WDV) infectious clones in the bacterial plasmids pUC18 and pIPKb002 and tested their ability to inoculate plants using Bio-Rad Helios Gene Gun biolistic inoculation method and Agrobacterium tumefaciens agroinoculation method, and we then compared them with the natural inoculation method via viruliferous P. alienus. Infected plants were generated using both infectious clones, whereas the agroinoculation method was able to produce strong systemic infection in all three tested cultivars of wheat and Triticum monococcum, comparable to plants inoculated by viruliferous P. alienus. Infection was confirmed by DAS-ELISA, and WDV titres were quantified using qPCR. The levels of remaining bacterial plasmid DNA were also confirmed to be zero.

scholarly journals Cucumber mosaic virus Establishes Systemic Infection at Increased Temperature Following Viral Entrance Into the Phloem Pathway of Tetragonia expansa

2003 ◽  
Vol 93 (11) ◽  
pp. 1445-1451 ◽  
Author(s):  
Takashi Kobori ◽  
Takeshi Osaki ◽  
Satoshi T. Ohki
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Cell Movement ◽  
Systemic Infection ◽  
Regulatory Site ◽  
Mesophyll Cells ◽  
Increased Temperature ◽  
Tetragonia Expansa ◽  
Internal Phloem

A potential regulatory site for Cucumber mosaic virus (CMV, pepo strain) movement necessary to establish systemic infection was identified through immunological and hybridization studies on Tetragonia expansa, which was systemically infected by CMV at 36°C but not at 24°C. In inoculated leaves, cell-to-cell movement of CMV was enhanced at 36°C compared with that observed at 24°C. CMV was distributed in the phloem cells of minor veins as well as epidermal and mesophyll cells at both 36 and 24°C. CMV was detected in the petioles of inoculated leaves, stems, and petioles of uninoculated upper leaves at 36°C, whereas CMV was detected only in the petioles of inoculated leaves and in stems at 24°C. CMV moved into the phloem and was transported to the stem within 24 h postinoculation (hpi) at 36°C. However, it did not accumulate in the petioles of the upper leaves until 36 hpi. In petioles of inoculated leaves at 24°C, CMV was detected in the external phloem but not in the internal phloem. From these results, we conclude that systemic infection is established after viral entrance into the phloem pathway in T. expansa at 36°C.

scholarly journals Compatibility of the movement protein and the coat protein of cucumoviruses is required for cell-to-cell movement

2004 ◽  
Vol 85 (4) ◽  
pp. 1039-1048 ◽  
Author(s):  
Katalin Salánki ◽  
Ákos Gellért ◽  
Emese Huppert ◽  
Gábor Náray-Szabó ◽  
Ervin Balázs
Keyword(s):  
Coat Protein ◽  
Movement Protein ◽  
Point Mutations ◽  
Cell Movement ◽  
Virus Movement ◽  
Tomato Aspermy Virus ◽  
Sequence Encoding ◽  
Surface Electrostatic Potential ◽  
Test Plants ◽  
Insight Into

For the cell-to-cell movement of cucumoviruses both the movement protein (MP) and the coat protein (CP) are required. These are not reversibly exchangeable between Cucumber mosaic virus (CMV) and Tomato aspermy virus (TAV). The MP of CMV is able to function with the TAV CP (chimera RT), but TAV MP is unable to promote the cell-to-cell movement in the presence of CMV CP (chimera TR). To gain further insight into the non-infectious nature of the TR recombinant, RNA 3 chimeras were constructed with recombinant MPs and CPs. The chimeric MP and one of the CP recombinants were infectious. The other recombinant CP enabled virus movement only after the introduction of two point mutations (Glu→Lys and Lys→Arg at aa 62 and 65, respectively). The mutations served to correct the CP surface electrostatic potential that was altered by the recombination. The infectivity of the TR virus on different test plants was restored by replacing the sequence encoding the C-terminal 29 aa of the MP with the corresponding sequence of the CMV MP gene or by exchanging the sequence encoding the C-terminal 15 aa of the CP with the same region of TAV. The analysis of the recombinant clones suggests a requirement for compatibility between the C-terminal 29 aa of the MP and the C-terminal two-thirds of the CP for cell-to-cell movement of cucumoviruses.

scholarly journals The Rate of Cell-to-Cell Movement in Squash of Cucumber Mosaic Virus Is Affected by Sequences of the Capsid Protein

1999 ◽  
Vol 12 (7) ◽  
pp. 628-632 ◽  
Author(s):  
Sek-Man Wong ◽  
Sharon Swee-Chin Thio ◽  
Michael H. Shintaku ◽  
Peter Palukaitis
Keyword(s):  
Amino Acids ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Capsid Protein ◽  
Cell Movement ◽  
Systemic Infection ◽  
Long Distance ◽  
Local Movement ◽  
Long Distance Movement

The M strain of cucumber mosaic virus (CMV) does not infect squash plants systemically and moves very slowly in inoculated cotyledons. Systemic infection and an increase in the rate of local movement were observed when amino acids 129 or 214 of the M-CMV capsid protein (CP) were altered to those present in the Fny strain of CMV. While the opposite alterations to the CP of Fny-CMV inhibited systemic infection of squash, they did not show the same effects on the rates of both cell-to-cell and long-distance movement. However, the ability of CMV to infect squash systemically was affected by the rate of cell-to-cell movement.

scholarly journals Tobacco rattle virus 29K Movement Protein Is the Elicitor of Extreme and Hypersensitive-like Resistance in Two Cultivars of Solanum tuberosum

2007 ◽  
Vol 20 (11) ◽  
pp. 1396-1405 ◽  
Author(s):  
Walid Ghazala ◽  
Mark Varrelmann
Keyword(s):  
Cell Death ◽  
Solanum Tuberosum ◽  
Virus Replication ◽  
Movement Protein ◽  
Tobacco Rattle Virus ◽  
Cell Movement ◽  
Systemic Infection ◽  
Potato Virus X ◽  
Host Responses ◽  
Cell Death Response

Leaf infection experiments were used to analyze the host responses of Solanum tuberosum cultivars known to be resistant or susceptible to natural, nematode-mediated infection of tubers and necrosis induction (“spraing”) by Tobacco rattle virus (TRV) isolate PpK20 (TRV-PpK20). Extreme and hypersensitive-like resistance (ER and HR-like, respectively) as well as spreading veinal necrosis and systemic infection were observed. Agroinfection of leaves with a DsRed-expressing TRV cDNA clone revealed ER to function on the single-cell level, inhibiting virus replication and possessing the potential to initiate a cell death response. HR-like necrosis was characterized by initial virus replication and cell-to-cell movement before the onset of necrosis. Transient agroexpression and Potato virus X (PVX)-mediated expression assays demonstrated that the 29K-PpK20 movement protein (MP) can elicit ER and HR-like cell-death. A TRV isolate, PpO85M, known to overcome the resistance to spraing in plants that are resistant to TRV-PpK20 encoded a variant 29K protein which did not elicit HR in PpK20-HR plants. Our results show that the TRV MP is the elicitor of both ER and HR-like cell-death, that no other TRV-encoded proteins or RNA replication are required for its elicitor activity, and that the host reactions are likely to be controlled by single dominant resistance genes.

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