scholarly journals Viral-Like Symptoms Induced by the Ectopic Expression of the p23 Gene of Citrus tristeza virus Are Citrus Specific and Do Not Correlate with the Pathogenicity of the Virus Strain

2005 ◽  
Vol 18 (5) ◽  
pp. 435-445 ◽  
Author(s):  
Carmen Fagoaga ◽  
Carmelo López ◽  
Pedro Moreno ◽  
Luis Navarro ◽  
Ricardo Flores ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Ectopic Expression ◽  
Sour Orange ◽  
Citrus Species ◽  
Mexican Lime ◽  
Symptom Intensity ◽  
P23 Gene ◽  
Tristeza Virus ◽  
Leaf Symptoms ◽  
Citrus Tristeza

Ectopic expression of the p23 gene from a severe (T36) strain of Citrus tristeza virus (CTV) induces viral-like symptoms in Mexican lime. Here, we report that expressing the same gene from a mild strain induced similar symptoms that correlated with accumulation of p23 protein irrespective of the source strain. CTV inoculation of transgenic limes showing CTV-like leaf symptoms and high p23 accumulation did not modify symptoms initially, with the virus titer being as in inoculated nontransgenic controls; however, at later stages, symptoms became attenuated. Transformation with p23-T36 of CTV-susceptible sweet and sour orange and CTV-resistant trifoliate orange also led to CTV-like leaf symptoms that did not develop when plants were transformed with a truncated p23 version. In transgenic citrus species and relatives other than Mexican lime, p23 was barely detectable, although symptom intensity correlated with levels of p23 transcripts. The lower accumulation of p23 in sweet and sour orange compared with Mexican lime also was observed in nontransgenic plants inoculated with CTV, suggesting that minimal p23 levels cause deleterious effects in the first two species. Conversely, transgenic expression of p23 in CTV nonhost Nicotiana spp. led to accumulation of p23 without phenotypic aberrations, indicating that p23 interferes with plant development only in citrus species and relatives.

scholarly journals Severity of Citrus tristeza virus Isolates from Texas

Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 575-580 ◽  
Author(s):  
C.M. Herron ◽  
T.E. Mirkov ◽  
N. N. Solís-Gracia ◽  
C.J. Kahlke ◽  
M. Skaria ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
South Texas ◽  
Sour Orange ◽  
Lower Rio Grande Valley ◽  
Mexican Lime ◽  
Single Stranded Conformational Polymorphism ◽  
Or Gene ◽  
Tristeza Virus ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) isolates collected from the Lower Rio Grande Valley in south Texas and east Texas were characterized using citrus indicators and molecular methods. The citrus indicators were Mexican lime (Citrus aurantifolia), sour orange (C. aurantium), sweet orange (C. sinensis) grafted to sour orange, Duncan grapefruit (C. × paradisi), and Madam Vinous sweet orange, with some CTV isolates additionally indexed using the Texas commercial grapefruit cvs. Rio Red and Star Ruby, and Marrs and N-33 sweet orange. Severity ratings used 11 biotype groups or cumulative mean relative indices. Molecular characterization was carried out using poly- and monoclonal antibodies, seven strain-specific probes and single-stranded conformational polymorphism, and all were based on the CTV major coat protein or gene. All Texas CTV isolates produced vein clearing symptoms on inoculated Mexican lime plants. Over half of the CTV isolates tested were placed in biotype groups IX and X (causing decline of sweet orange on sour orange, seedling yellows on sour orange and grapefruit seedlings, and stem pitting of grapefruit or sweet orange), and one isolate was in biotype I (mild).

scholarly journals Citrus Tristeza Virus: Survival at the Edge of the Movement Continuum

2008 ◽  
Vol 82 (13) ◽  
pp. 6546-6556 ◽  
Author(s):  
Svetlana Y. Folimonova ◽  
Alexey S. Folimonov ◽  
Satyanarayana Tatineni ◽  
William O. Dawson
Keyword(s):  
Citrus Tristeza Virus ◽  
Cell Movement ◽  
Systemic Infection ◽  
Sour Orange ◽  
Citrus Species ◽  
Long Distance ◽  
Susceptible Host ◽  
Long Distance Movement ◽  
Tristeza Virus ◽  
Citrus Tristeza

ABSTRACT Systemic invasion of plants by viruses is thought to involve two processes: cell-to-cell movement between adjacent cells and long-distance movement that allows the virus to rapidly move through sieve elements and unload at the growing parts of the plant. There is a continuum of proportions of these processes that determines the degrees of systemic infection of different plants by different viruses. We examined the systemic distribution of Citrus tristeza virus (CTV) in citrus species with a range of susceptibilities. By using a “pure” culture of CTV from a cDNA clone and green fluorescent protein-labeled virus we show that both cell-to-cell and long-distance movement are unusually limited, and the degree of limitation varies depending on the citrus host. In the more-susceptible hosts CTV infected only a small portion of phloem-associated cells, and moreover, the number of infection sites in less-susceptible citrus species was substantially decreased further, indicating that long-distance movement was reduced in those hosts. Analysis of infection foci in the two most differential citrus species, Citrus macrophylla and sour orange, revealed that in the more-susceptible host the infection foci were composed of a cluster of multiple cells, while in the less-susceptible host infection foci were usually single cells, suggesting that essentially no cell-to-cell movement occurred in the latter host. Thus, CTV in sour orange represents a pattern of systemic infection in which the virus appears to function with only the long-distance movement mechanism, yet is able to survive in nature.

scholarly journals First Report from Syria of Citrus tristeza virus in Citrus spp.

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1468-1468
Author(s):  
R. Abou Kubaa ◽  
K. Djelouah ◽  
A. M. D'Onghia ◽  
R. Addante ◽  
M. Jamal
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Citrus Limon ◽  
Potential Threat ◽  
First Report ◽  
Mexican Lime ◽  
Vein Clearing ◽  
Citrus Varieties ◽  
Tristeza Virus ◽  
Citrus Tristeza

During the spring of 2006, the main Syrian citrus-growing areas of Lattakia (Jableh, Aledyye, Eseelya, Siano, and Hresoon provinces) and Tartous (Almintar, Aljammase, Karto, Majdaloonelbahr, Yahmour, Amreet, Althawra, and Safita provinces) were surveyed to assess the presence of Citrus tristeza virus (CTV). Eight nurseries (approximately 130 plants per nursery), two budwood source fields (approximately 230 trees per field), and 19 groves (approximately 60 trees per grove) containing the main citrus varieties were visually inspected and sampled for serological assays. The hierarchical sampling method was carried out in each selected grove (2). Infected samples were collected from two nurseries, two budwood source fields, and six groves. Stems and leaf petioles from nursery trees and flower explants from the groves were collected and analyzed for CTV by direct tissue blot immunoassay (DTBIA) with the commercial kit from Plantprint (Valencia, Spain). Of 2,653 samples tested, 89 (4%) CTV-infected plants were detected. Five citrus varieties were found to be infected and Meyer lemon (Citrus limon ‘Meyer’) had the highest incidence at 16%. Numerous sweet orange varieties (Citrus sinensis L.) were found to be highly infected in the field, but only the Washington navel sweet orange was found to be infected in the nurseries. No clear CTV symptoms were observed during the survey. Samples that were positive for CTV by DTBIA were also positive by biological indexing on Mexican lime (C. aurantifolia) and immunocapture-reverse transcription-PCR as described by Nolasco et al. (3). Coat protein gene sequences obtained from five selected clones of a Syrian CTV isolate (GenBank Accession No. EU626555) showed more than 99 and 98% nucleotide sequence identity to a Jordanian CTV isolate (GenBank Accession No. AY550252) and the VT isolate (GenBank Accession No. U56902), respectively. Almost all infected samples induced moderate vein clearing symptoms when grafted to Mexican lime. Symptoms of vein clearing, leaf cupping, stunting, and stem pitting on Mexican lime were induced by graft transmission of CTV from one Valencia sample from the Tartous area. The viral inoculum is widely and randomly distributed in commercial groves, especially in the southern Tartous area and in some nurseries. To our knowledge, this is the first report of CTV in Syria. However, CTV was reported from the neighboring citrus-growing countries of Lebanon, Turkey, and Jordan (1), and the severe seedling yellows strain is present in this area, which poses a potential threat to Syrian citriculture. References: (1) G. H. Anfoka et al. Phytopathol. Mediterr. 44:17, 2005. (2) G. Hughes and T. R. Gottwald, Phytopathology 88:715, 1998. (3) G. Nolasco et al. Eur. J. Plant Pathol. 108:293, 2002.

scholarly journals Cross-Protection of Grapefruit from Decline-Inducing Isolates of Citrus Tristeza Virus

Plant Disease ◽  
1999 ◽  
Vol 83 (11) ◽  
pp. 989-991 ◽  
Author(s):  
C. A. Powell ◽  
R. R. Pelosi ◽  
P. A. Rundell ◽  
E. Stover ◽  
M. Cohen
Keyword(s):  
Citrus Tristeza Virus ◽  
Natural Infection ◽  
Tree Height ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sour Orange ◽  
River Region ◽  
Indian River ◽  
Tristeza Virus ◽  
Better Than ◽  
Citrus Tristeza

The ability of three mild isolates of citrus tristeza virus (CTV) to prevent natural infection of 84 Ruby Red grapefruit on sour orange rootstock by aphid-transmitted, decline-inducing isolates of CTV was assessed by symptoms and verified by enzyme-linked immunosorbent assay (ELISA) after 16 years. Of 21 trees in each of four treatments protected by the DD 102 bb, Guettler HS, and DPI 1-12-5-X-E mild CTV isolates, 14, 10, and 14% were infected by severe isolates (MCA13 monoclonal antibody reactive) compared with 67% for unprotected control trees. The health of trees protected by the DD 102 bb CTV isolate was significantly better than that of unprotected control trees as measured by decline, tree ratings, and tree height. These data suggest that infection by certain mild isolates of CTV can cross-protect grapefruit trees on sour orange rootstock from decline-inducing isolates of CTV that are prevalent in the Indian River region of Florida.

scholarly journals Ectopic expression of the p23 silencing suppressor of Citrus tristeza virus differentially modifies viral accumulation and tropism in two transgenic woody hosts

2011 ◽  
Vol 12 (9) ◽  
pp. 898-910 ◽  
Author(s):  
CARMEN FAGOAGA ◽  
GIOVANNI PENSABENE-BELLAVIA ◽  
PEDRO MORENO ◽  
LUÍS NAVARRO ◽  
RICARDO FLORES ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Ectopic Expression ◽  
Silencing Suppressor ◽  
Tristeza Virus ◽  
Viral Accumulation ◽  
Citrus Tristeza

scholarly journals Field Diagnosis of Citrus Tristeza Virus

EDIS ◽  
1969 ◽  
Vol 2005 (1) ◽  
Author(s):  
Stephen H. Futch ◽  
Ronald H. Brlansky
Keyword(s):  
Citrus Tristeza Virus ◽  
Cooperative Extension Service ◽  
Extension Service ◽  
Tree Decline ◽  
Sour Orange ◽  
University Of Florida ◽  
Nursery Trees ◽  
Citrus Macrophylla ◽  
Tristeza Virus ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) is one of the most important pathogens affecting citrus worldwide. Tristeza was first reported in Florida in the 1950s. By the 1980s, it produced serious losses due to tree decline and death on sour orange and Citrus macrophylla rootstocks. Tree decline continues to be a problem today in groves that still have sour orange rootstock trees remaining. Due to CTV, few if any nursery trees are being propagated in Florida on sour orange, bittersweet or Citrus macrophylla rootstock. This document is HS996, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published February 2005. HS996/HS242: Field Diagnosis of Citrus Tristeza Virus (ufl.edu)

scholarly journals The p23 Protein of Citrus Tristeza Virus Controls Asymmetrical RNA Accumulation

2002 ◽  
Vol 76 (2) ◽  
pp. 473-483 ◽  
Author(s):  
Tatineni Satyanarayana ◽  
Siddarame Gowda ◽  
María A. Ayllón ◽  
María R. Albiach-Martí ◽  
Shailaja Rabindran ◽  
...  
Keyword(s):  
Amino Acid ◽  
Zinc Finger ◽  
Citrus Tristeza Virus ◽  
Rna Binding ◽  
Fold Increase ◽  
Amino Acid Residues ◽  
Rna Accumulation ◽  
P23 Gene ◽  
Tristeza Virus ◽  
Citrus Tristeza

ABSTRACT Citrus tristeza virus (CTV), a member of the Closteroviridae, has a 19.3-kb positive-stranded RNA genome that is organized into 12 open reading frames (ORFs) with the 10 3′ genes expressed via a nested set of nine or ten 3′-coterminal subgenomic mRNAs (sgRNAs). Relatively large amounts of negative-stranded RNAs complementary to both genomic and sgRNAs accumulate in infected cells. As is characteristic of RNA viruses, wild-type CTV produced more positive than negative strands, with the plus-to-minus ratios of genomic and sgRNAs estimated at 10 to 20:1 and 40 to 50:1, respectively. However, a mutant with all of the 3′ genes deleted replicated efficiently, but produced plus to minus strands at a markedly decreased ratio of 1 to 2:1. Deletion analysis of 3′-end genes revealed that the p23 ORF was involved in asymmetric RNA accumulation. A mutation which caused a frameshift after the fifth codon resulted in nearly symmetrical RNA accumulation, suggesting that the p23 protein, not a cis-acting element within the p23 ORF, controls asymmetric accumulation of CTV RNAs. Further in-frame deletion mutations in the p23 ORF suggested that amino acid residues 46 to 180, which contained RNA-binding and zinc finger domains, were indispensable for asymmetrical RNA accumulation, while the N-terminal 5 to 45 and C-terminal 181 to 209 amino acid residues were not absolutely required. Mutation of conserved cysteine residues to alanines in the zinc finger domain resulted in loss of activity of the p23 protein, suggesting involvement of the zinc finger in asymmetric RNA accumulation. The absence of p23 gene function was manifested by substantial increases in accumulation of negative-stranded RNAs and only modest decreases in positive-stranded RNAs. Moreover, the substantial decrease in the accumulation of negative-stranded coat protein (CP) sgRNA in the presence of the functional p23 gene resulted in a 12- to 15-fold increase in the expression of the CP gene. Apparently the excess negative-stranded sgRNA reduces the availability of the corresponding positive-stranded sgRNA as a messenger. Thus, the p23 protein controls asymmetric accumulation of CTV RNAs by downregulating negative-stranded RNA accumulation and indirectly increases expression of 3′ genes.

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