scholarly journals The Capsid Protein of Satellite Panicum Mosaic Virus Contributes to Systemic Invasion and Interacts with Its Helper Virus

2005 ◽  
Vol 79 (15) ◽  
pp. 9756-9764 ◽  
Author(s):  
Rustem T. Omarov ◽  
Dong Qi ◽  
Scholthof G. Karen-Beth

ABSTRACT Satellite panicum mosaic virus (SPMV) depends on its helper Panicum mosaic virus (PMV) for replication and spread in host plants. The SPMV RNA encodes a 17-kDa capsid protein (CP) that is essential for formation of its 16-nm virions. The results of this study indicate that in addition to the expression of the full-length SPMV CP from the 5′-proximal AUG start codon, SPMV RNA also expresses a 9.4-kDa C-terminal protein from the third in-frame start codon. Differences in solubility between the full-length protein and its C-terminal product were observed. Subcellular fractionation of infected plant tissues showed that SPMV CP accumulates in the cytosol, cell wall-, and membrane-enriched fractions. However, the 9.4-kDa protein exclusively cofractionated with cell wall- and membrane-enriched fractions. Earlier studies revealed that the 5′-untranslated region (5′-UTR) from nucleotides 63 to 104 was associated with systemic infection in a host-specific manner in millet plants. This study shows that nucleotide deletions and insertions in the 5′-UTR plus simultaneous truncation of the N-terminal part of the CP impaired SPMV spread in foxtail millet, but not in proso millet plants. In contrast, the expression of the full-length version of SPMV CP efficiently compensated the negative effect of the 5′-UTR deletions in foxtail millet. Finally, immunoprecipitation assays revealed the presence of a specific interaction between the capsid proteins of SPMV and its helper virus (PMV). Our findings show that the SPMV CP has several biological functions, including facilitating efficient satellite virus infection and movement in millet plants.

2002 ◽  
Vol 15 (10) ◽  
pp. 1050-1057 ◽  
Author(s):  
Yongzhong Li ◽  
Scott M. Leisner

The Cauliflower mosaic virus (CaMV) gene VI product (P6) is a multifunctional protein essential for viral propagation. It is likely that at least some of these functions require P6 self-association. The work described here was performed to confirm that P6 self-associates and to identify domains involved in this interaction. Yeast two-hybrid analyses indicated that full-length P6 self-associates and that this interaction is specific. Additional analyses indicated that at least four independent domains bind to full-length P6. When a central domain (termed domain D3) was removed, these interactions were abolished. However, this deleted P6 was able to bind to the full-length wild-type protein and to isolated domain D3. Viruses lacking domain D3 were incapable of producing a systemic infection. Isolated domain D3 was capable of binding to at least two of the other domains but was unable to self-associate. This suggests that domain D3 facilitates P6 self-association by binding to the other domains but not itself. The presence of multiple domains involved in P6 self-association may help explain the ability of this protein to form the intracellular inclusions characteristic of caulimoviruses.


1999 ◽  
Vol 12 (7) ◽  
pp. 628-632 ◽  
Author(s):  
Sek-Man Wong ◽  
Sharon Swee-Chin Thio ◽  
Michael H. Shintaku ◽  
Peter Palukaitis

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.


2004 ◽  
Vol 17 (3) ◽  
pp. 263-271 ◽  
Author(s):  
Wenping Qiu ◽  
Karen-Beth G. Scholthof

The capsid protein (CP) of satellite panicum mosaic virus (SPMV) has been implicated as a pathogenicity factor, inducing severe chlorosis on millet plants co-infected with SPMV and its helper virus, Panicum mosaic virus (PMV). In this study, we tested the effects of SPMV CP on Nicotiana benthamiana, a plant that does not support PMV+SPMV infections. SPMV CP expressed from a Potato virus X (PVX) gene vector elicited necrotic lesions on N. benthamiana. Pathogenicity factors often have the additional feature of acting as suppressors of gene silencing; therefore, several assays were developed to test if SPMV CP could act in such a capacity. The results showed that SPMV CP failed to act as a suppressor of posttranscriptional gene silencing when such tests were performed with transgenic N. benthamiana plants silenced for green fluorescent protein (GFP) expression by agroinfiltration or plant virus vectors. However SPMV CP expressed from the PVX gene vector did interfere with suppressor activity associated with PVX p25. This included a rebounded level of GFP silencing along the vascular tissues, including the veins on upper noninoculated leaves. Therefore, the roles of the SPMV CP now include encapsidation of the SPMV RNA, activity as a pathogenicity factor in both host and nonhost plants, and the enigmatic feature of interfering with suppression of gene silencing.


1996 ◽  
Vol 74 (6) ◽  
pp. 939-951 ◽  
Author(s):  
O. Rohfritsch ◽  
A. Poirson ◽  
M.-J. Gagey ◽  
C. Stussi-Garaud ◽  
T. Godefroy-Colburn ◽  
...  

A modified form of the movement protein (P3) of alfalfa mosaic virus, lacking amino acids 21 to 34, was transgenically expressed in Nicotiana tabacum cv. Xanthi (genotype nn) and cv. Xanthi nc (genotype NN). The modified protein (designated P3Δ[21–34]) was expressed more strongly than the full-length protein. The localization of P3Δ[21–34] was investigated by subcellular fractionation and immunocytochemistry. Immunolabelling was most frequent in vascular parenchymal cells, mainly in the cytoplasm (endoplasmic reticulum, Golgi, plasma membrane vesicles) but also in the cell wall. In contrast, full-length P3 accumulated almost exclusively in a cell-wall enriched fraction. Transgenically expressed P3Δ[21–34] increased the plasmodesmal gating capacity of epidermal cells, as did transgenically expressed P3. Thus, the plasmodesma-gating domain of P3 does not include amino acids 21 to 34. Plants expressing P3Δ[21–34] at a high level exhibited stressed phenotypes. Phenotype 1, only observed in 'Xanthi' NN lines, was characterized by stunting, small, thick, and hairy leaves, locally high starch accumulation, and occasional necrotic cells, mainly in the bundle sheath and vascular tissue. Phenotype 2, observed in both 'Xanthi' NN and nn lines, was characterized by short internodes, numerous small green leaves, sterile flowers, regular starch accumulation, and absence of necrotic cells. The stress-inducing activity of P3Δ[21–34] may be due to either its molecular conformation or its low efficiency of export toward the cell wall. Keywords: cell to cell movement, stress reaction, plasmodesmata, transgenic plant, ultrastructure, immunocytochemistry.


2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 542-544
Author(s):  
R. Pokorný ◽  
M. Porubová

Under greenhouse conditions 12 maize hybrids derived from crosses of four resistant lines with several lines of different level of susceptibility were evaluated for resistance to Czech isolate of Sugarcane mosaic virus (SCMV). These hybrids were not fully resistant to isolate of SCMV, but the symptoms on their newly growing leaves usually developed 1 to 3 weeks later in comparison with particular susceptible line, the course of infection was significantly slower and rate of infection lower. As for mechanisms of resistance, the presence of SCMV was detected by ELISA in inoculated leaves both of resistant and susceptible lines, but virus was detected 7 days later in resistant line. Systemic infection developed only in susceptible lines. These results indicate restriction of viral long distance movement in the resistant line.


Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 392
Author(s):  
Haomiao Cheng ◽  
Chris Bowler ◽  
Xiaohui Xing ◽  
Vincent Bulone ◽  
Zhanru Shao ◽  
...  

β-Chitin produced by diatoms is expected to have significant economic and ecological value due to its structure, which consists of parallel chains of chitin, its properties and the high abundance of diatoms. Nevertheless, few studies have functionally characterised chitin-related genes in diatoms owing to the lack of omics-based information. In this study, we first compared the chitin content of three representative Thalassiosira species. Cell wall glycosidic linkage analysis and chitin/chitosan staining assays showed that Thalassiosira weissflogii was an appropriate candidate chitin producer. A full-length (FL) transcriptome of T. weissflogii was obtained via PacBio sequencing. In total, the FL transcriptome comprised 23,362 annotated unigenes, 710 long non-coding RNAs (lncRNAs), 363 transcription factors (TFs), 3113 alternative splicing (AS) events and 3295 simple sequence repeats (SSRs). More specifically, 234 genes related to chitin metabolism were identified and the complete biosynthetic pathways of chitin and chitosan were explored. The information presented here will facilitate T. weissflogii molecular research and the exploitation of β-chitin-derived high-value enzymes and products.


2021 ◽  
Vol 166 (5) ◽  
pp. 1427-1431
Author(s):  
Buyang Chen ◽  
Qi Lin ◽  
Yueyan Yin ◽  
Liangliang Jiang ◽  
Fang Wang ◽  
...  

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Zhi-Yong Yan ◽  
Xiao-Jie Xu ◽  
Le Fang ◽  
Chao Geng ◽  
Yan-Ping Tian ◽  
...  

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.


Virus Genes ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 233-237
Author(s):  
Hendrik Reuper ◽  
Björn Krenz

AbstractTurnip mosaic virus (TuMV), belonging to the genus Potyvirus (family Potyviridae), has a large host range and consists of a single-stranded positive sense RNA genome encoding 12 proteins, including the P1 protease. This protein which is separated from the polyprotein by cis cleavage at its respective C-terminus, has been attributed with different functions during potyviral infection of plants. P1 of Turnip mosaic virus (P1-TuMV) harbors an FGSF-motif and FGSL-motif at its N-terminus. This motif is predicted to be a binding site for the host Ras GTPase-activating protein-binding protein (G3BP), which is a key factor for stress granule (SG) formation in mammalian systems and often targeted by viruses to inhibit SG formation. We therefore hypothesized that P1-TuMV might interact with G3BP to control and regulate plant SGs to optimize cellular conditions for the production of viral proteins. Here, we analyzed the co-localization of the Arabidopsis thaliana G3BP-2 with the P1 of two TuMV isolates, namely UK 1 and DEU 2. Surprisingly, P1-TuMV-DEU 2 co-localized with AtG3BP-2 under abiotic stress conditions, whereas P1-TuMV-UK 1 did not. AtG3BP-2::RFP showed strong SGs formation after stress, while P1-UK 1::eGFP maintained a chloroplastic signal under stress conditions, the signal of P1-DEU 2::eGFP co-localized with that of AtG3BP-2::RFP. This indicates a specific interaction between P1-DEU 2 and the AtG3BP family which is not solely based on the canonical interaction motifs.


Sign in / Sign up

Export Citation Format

Share Document