scholarly journals The C-terminus of Wheat streak mosaic virus Coat Protein Is Involved in Differential Infection of Wheat and Maize through Host-Specific Long-Distance Transport

2014 ◽  
Vol 27 (2) ◽  
pp. 150-162 ◽  
Author(s):  
Satyanarayana Tatineni ◽  
Roy French
Keyword(s):  
Amino Acid ◽  
Host Range ◽  
Mosaic Virus ◽  
Aspartic Acid ◽  
Wheat Streak Mosaic Virus ◽  
Coat Proteins ◽  
Long Distance ◽  
Long Distance Transport ◽  
C Terminus ◽  
Distance Transport

Viral determinants and mechanisms involved in extension of host range of monocot-infecting viruses are poorly understood. Viral coat proteins (CP) serve many functions in almost every aspect of the virus life cycle. The role of the C-terminal region of Wheat streak mosaic virus (WSMV) CP in virus biology was examined by mutating six negatively charged aspartic acid residues at positions 216, 289, 290, 326, 333, and 334. All of these amino acid residues are dispensable for virion assembly, and aspartic acid residues at positions 216, 333, and 334 are expendable for normal infection of wheat and maize. However, mutants D289N, D289A, D290A, DD289/290NA, and D326A exhibited slow cell-to-cell movement in wheat, which resulted in delayed onset of systemic infection, followed by a rapid recovery of genomic RNA accumulation and symptom development. Mutants D289N, D289A, and D326A inefficiently infected maize, eliciting milder symptoms, while D290A and DD289/290NA failed to infect systemically, suggesting that the C-terminus of CP is involved in differential infection of wheat and maize. Mutation of aspartic acid residues at amino acid positions 289, 290, and 326 severely debilitated virus ingress into the vascular system of maize but not wheat, suggesting that these amino acids facilitate expansion of WSMV host range through host-specific long-distance transport.

scholarly journals Temperature-Dependent Wsm1 and Wsm2 Gene-Specific Blockage of Viral Long-Distance Transport Provides Resistance to Wheat streak mosaic virus and Triticum mosaic virus in Wheat

2016 ◽  
Vol 29 (9) ◽  
pp. 724-738 ◽  
Author(s):  
Satyanarayana Tatineni ◽  
Everlyne N. Wosula ◽  
Melissa Bartels ◽  
Gary L. Hein ◽  
Robert A. Graybosch
Keyword(s):  
Mosaic Virus ◽  
Fluorescent Protein ◽  
Wheat Streak Mosaic Virus ◽  
Viral Resistance ◽  
Wheat Cultivars ◽  
Temperature Dependent ◽  
Long Distance ◽  
Long Distance Transport ◽  
Long Distance Movement ◽  
Distance Transport

Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are economically important viral pathogens of wheat. Wheat cvs. Mace, carrying the Wsm1 gene, is resistant to WSMV and TriMV, and Snowmass, with Wsm2, is resistant to WSMV. Viral resistance in both cultivars is temperature sensitive and is effective at 18°C or below but not at higher temperatures. The underlying mechanisms of viral resistance of Wsm1 and Wsm2, nonallelic single dominant genes, are not known. In this study, we found that fluorescent protein–tagged WSMV and TriMV elicited foci that were approximately similar in number and size at 18 and 24°C, on inoculated leaves of resistant and susceptible wheat cultivars. These data suggest that resistant wheat cultivars at 18°C facilitated efficient cell-to-cell movement. Additionally, WSMV and TriMV efficiently replicated in inoculated leaves of resistant wheat cultivars at 18°C but failed to establish systemic infection, suggesting that Wsm1- and Wsm2-mediated resistance debilitated viral long-distance transport. Furthermore, we found that neither virus was able to enter the leaf sheaths of inoculated leaves or crowns of resistant wheat cultivars at 18°C but both were able to do so at 24°C. Thus, wheat cvs. Mace and Snowmass provide resistance at the long-distance movement stage by specifically blocking virus entry into the vasculature. Taken together, these data suggest that both Wsm1 and Wsm2 genes similarly confer virus resistance by temperature-dependent impairment of viral long-distance movement.

scholarly journals Monoclonal Antibodies Detect a Single Amino Acid Difference Between the Coat Proteins of Soilborne Wheat Mosaic Virus Isolates: Implications for Virus Structure

1997 ◽  
Vol 87 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Jianping Chen ◽  
Lesley Torrance ◽  
Graham H. Cowan ◽  
Stuart A. MacFarlane ◽  
Gerald Stubbs ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Mosaic Virus ◽  
Single Amino Acid ◽  
Computer Assisted ◽  
Amino Acid Difference ◽  
Coat Proteins ◽  
C Terminus ◽  
Readthrough Protein

Four monoclonal antibodies (MAbs) were prepared against an isolate of soilborne wheat mosaic furovirus from Oklahoma (SBWMV Okl-7). Three MAbs had different reactivities in tests on SBWMV isolates from Nebraska (Lab1), France, and Japan. One MAb (SCR 133) also reacted with oat golden stripe furovirus. None of the MAbs cross-reacted with other rod-shaped viruses including beet necrotic yellow vein furovirus, potato mop-top furovirus, and tobacco rattle tobravirus. Sequence analysis of nucleotides between 334 and 1,000 of RNA 2, the region that encodes the coat protein (CP) and the first 44 amino acids of a readthrough protein, of the four SBWMV isolates revealed up to 27 base changes from the published sequence of a Nebraska field isolate of SBWMV. Most changes were translationally silent, but some caused differences of one to three amino acids in residues located near either the N- or C-terminus of the CPs of the different isolates. Two further single amino acid changes were found at the beginning of the readthrough domain of the CP-readthrough protein. Some of these amino acid changes could be discriminated by MAbs SCR 132, SCR 133, and SCR 134. Peptide scanning (Pepscan) analysis indicated that the epitope recognized by SCR 134 is located near the N-terminus of the CP. SCR 132 was deduced to react with a discontinuous CP epitope near the C-terminus, and SCR 133 reacted with a surface-located continuous epitope also near the C-terminus. Predictions of CP structure from computer-assisted three-dimensional model building, by comparison with the X-ray fiber diffraction structure of tobacco mosaic virus, suggested that the three CP amino acids found to differ between isolates of SBWMV were located near the viral surface and were in regions predicted to be antigenic.

scholarly journals Unravelling the involvement of cilevirus p32 protein in the viral transport

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mikhail Oliveira Leastro ◽  
Juliana Freitas-Astúa ◽  
Elliot Watanabe Kitajima ◽  
Vicente Pallás ◽  
Jesús A. Sánchez-Navarro
Keyword(s):  
Functional Study ◽  
Cell Periphery ◽  
Long Distance ◽  
Viral Spread ◽  
Long Distance Transport ◽  
Viral Transport ◽  
C Terminus ◽  
Citrus Leprosis ◽  
Distance Transport

AbstractCitrus leprosis (CL) is a severe disease that affects citrus orchards mainly in Latin America. It is caused by Brevipalpus-transmitted viruses from genera Cilevirus and Dichorhavirus. Currently, no reports have explored the movement machinery for the cilevirus. Here, we have performed a detailed functional study of the p32 movement protein (MP) of two cileviruses. Citrus leprosis-associated viruses are not able to move systemically in neither their natural nor experimental host plants. However, here we show that cilevirus MPs are able to allow the cell-to-cell and long-distance transport of movement-defective alfalfa mosaic virus (AMV). Several features related with the viral transport were explored, including: (i) the ability of cilevirus MPs to facilitate virus movement on a nucleocapsid assembly independent-manner; (ii) the generation of tubular structures from transient expression in protoplast; (iii) the capability of the N- and C- terminus of MP to interact with the cognate capsid protein (p29) and; (iv) the role of the C-terminus of p32 in the cell-to-cell and long-distance transport, tubule formation and the MP-plasmodesmata co-localization. The MP was able to direct the p29 to the plasmodesmata, whereby the C-terminus of MP is independently responsible to recruit the p29 to the cell periphery. Furthermore, we report that MP possess the capacity to enter the nucleolus and to bind to a major nucleolar protein, the fibrillarin. Based on our findings, we provide a model for the role of the p32 in the intra- and intercellular viral spread.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

Sign in / Sign up

Export Citation Format

Share Document