scholarly journals Stem-Pitting Citrus tristeza virus Predominantly Transmitted by the Brown Citrus Aphid from Mixed Infections Containing Non-Stem-Pitting and Stem-Pitting Isolates

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 913-920 ◽  
Author(s):  
R. H. Brlansky ◽  
Avijit Roy ◽  
V. D. Damsteegt
Keyword(s):  
Citrus Tristeza Virus ◽  
Fruit Size ◽  
Haplotype Diversity ◽  
Aphid Transmission ◽  
Single Strand Conformation Polymorphism ◽  
Mixed Infections ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Spp ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) is a phloem-limited Closterovirus that produces a variety of symptoms in various Citrus spp. One of these symptoms is stem pitting (SP). SP does not occur in all Citrus spp. but when it does it may cause low tree vigor, decline, and an economic reduction in fruit size and yield. Historically, the first appearance of CTV-SP in a citrus area often occurs after the introduction of the most efficient CTV vector, the brown citrus aphid (BCA), Toxoptera citricida. Hypotheses for this association range from the introduction of these strains in new planting materials to the increased ability of BCA to transmit SP strains from existing CTV sources. It is known that CTV often exists as a complex of isolates or subisolates. Single and multiple BCA transmissions have been used to separate different genotypes or strains of CTV from mixed CTV infected plants. This study was initiated to determine what the BCA transmits when an exotic severe SP CTV isolate B12 from Brazil or B408 from Dominican Republic are mixed with a non-SP (NSP) isolate, FS627 from Florida. Biological and molecular data was generated from grafted mixtures of these isolates and their aphid-transmitted subisolates. Single-strand conformation polymorphism patterns of the 5′ terminal region of open reading frame (ORF) 1a, the overlapping region of ORF1b and ORF2, and the major coat protein gene region of NSP and SP CTV-grafted plants remained unchanged but the patterns of doubly inoculated plants varied. The haplotype diversity within SP isolates B12, B408, and mixtures of NSP and SP isolates (FS627/B12 and FS627/B408) and aphid-transmitted subisolates from doubly inoculated plants was determined by analysis of the haplotype nucleotide sequences. Aphid transmission experiments, symptoms, and molecular analyses showed that SP-CTV was more frequently transmitted with or without NSP-CTV from mixed infections.

scholarly journals Citrus Tristeza Virus Isolates of the Same Genotype Differ in Stem Pitting Severity in Grapefruit

Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2362-2368
Author(s):  
Glynnis Cook ◽  
Beatrix Coetzee ◽  
Rachelle Bester ◽  
Johannes H. J. Breytenbach ◽  
Chanel Steyn ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Common Source ◽  
Citrus Paradisi ◽  
Full Genome ◽  
Full Genome Sequencing ◽  
Reading Frame ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Two isolates of the T68 genotype of citrus tristeza virus (CTV) were derived from a common source, GFMS12, by single aphid transmission. These isolates, named GFMS12-8 and GFMS12-1.3, induced stem pitting with differing severity in ‘Duncan’ grapefruit (Citrus × paradisi [Macfad.]). Full-genome sequencing of these isolates showed only minor nucleotide sequence differences totaling 45 polymorphisms. Numerous nucleotide changes, in relatively close proximity, were detected in the p33 open reading frame (ORF) and the leader protease domains of ORF1a. This is the first report of full-genome characterization of CTV isolates of a single genotype, derived from the same source, but showing differences in pathogenicity. The results demonstrate the development of intragenotype heterogeneity known to occur with single-stranded RNA viruses. Identification of genetic variability between isolates showing different pathogenicity will enable interrogation of specific genome regions for potential stem pitting determinants.

Citrus tristeza virus (citrus tristeza).

2021 ◽  
Author(s):  
Mariano Cambra
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Salt Content ◽  
Fruit Size ◽  
Soil Conditions ◽  
Sour Orange ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
The Mediterranean Basin ◽  
Citrus Tristeza

Abstract CTV is the most economically important virus pathogen of citrus worldwide. About 100 million citrus trees on sour orange have been killed by CTV decline epidemics in Argentina, Brazil, Venezuela, Peru, Florida and California (USA), Israel, Spain, and other locations. With current estimates of approximately 45 million trees on sour orange killed by CTV in Spain (Cambra et al., 2000a; Vidal et al., 2012) from 1935 to date without T. citricida implication. It is estimated that worldwide, mainly in the Mediterranean basin citrus industries, there are over 200 million trees on sour orange rootstock which are at risk to this disease. Sour orange is popular because it produces a vigorous tree with high quality fruit, is adaptable to many soil conditions including high lime and salt content, and has tolerance to many other viruses, viroids and virus-like pathogens, and to Phytophthora. The use of tristeza-tolerant rootstocks often risks losses from other factors. In addition to decline, many severe CTV isolates cause stem pitting diseases of susceptible scion cultivars and these occur even when tolerant rootstocks are used. Stem pitting weakens trees and eventually reduces fruit size, quality and quantity (Marais et al., 1996). Grapefruit and lime are very sensitive to stem pitting. Sweet orange is more tolerant but can be severely affected by some isolates. Mandarin is the most tolerant among the main citrus cultivars against SP isolates.

scholarly journals Citrus Tristeza Virus: Molecular Approaches to Cross Protection

1994 ◽  
Author(s):  
William O. Dawson ◽  
Moshe Bar-Joseph ◽  
Charles L. Niblett ◽  
Ron Gafny ◽  
Richard F. Lee ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Complex Structure ◽  
Genetic System ◽  
Aphid Transmission ◽  
Open Reading Frames ◽  
Molecular Approaches ◽  
Defective Rnas ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) has the largest genomes among RNA viruses of plants. The 19,296-nt CTV genome codes for eleven open reading frames (ORFs) and can produce at least 19 protein products ranging in size from 6 to 401 kDa. The complex biology of CTV results in an unusual composition of CTV-specific RNAs in infected plants which includes multiple defective RNAs and mixed infections. The complex structure of CTV populations poses special problems for diagnosis, strain differentiation, and studies of pathogenesis. A manipulatable genetic system with the full-length cDNA copy of the CTV genome has been created which allows direct studies of various aspects of the CTV biology and pathology. This genetic system is being used to identify determinants of the decline and stem-pitting disease syndromes, as well as determinants responsible for aphid transmission.

scholarly journals Histology of Sweet Orange Stem Pitting Caused by an Australian Isolate of Citrus tristeza virus

Plant Disease ◽  
2002 ◽  
Vol 86 (10) ◽  
pp. 1169-1174 ◽  
Author(s):  
R. H. Brlansky ◽  
D. S. Howd ◽  
P. Broadbent ◽  
V. D. Damsteegt
Keyword(s):  
Electron Microscopy ◽  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Light And Electron Microscopy ◽  
Fruit Size ◽  
Australian Isolate ◽  
Thin Sections ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Some strains of the Citrus tristeza virus (CTV) cause stem pitting in sweet orange (Citrus sinensis (L.) Osbeck). This abnormality causes tree decline and reduction in fruit size and yield of affected citrus trees. Stem-pitting symptoms can occur on trunks, on all sizes of limbs, and on the twigs where fruit are produced. Variously sized pits or grooves in the wood often contain a yellow gum. Irregular growth of the phloem occurs in the area of these xylem pits. The histology of stem pitting caused by an Australian CTV isolate was studied in sweet orange using light and electron microscopy. Using scanning electron microscopy, details of the wood pits containing the gumming material were revealed. In thin sections of bark tissue, outgrowths of the phloem tissue were found at various intervals that corresponded to the pits in the wood. Higher numbers of viral inclusions were detected in the phloem outgrowths than were present in the other sieve elements.

Production of Antibodies to Citrus Tristeza Virus in Transgenic Citrus

1995 ◽  
Author(s):  
Richard Lee ◽  
Moshe Bar-Joseph ◽  
K.S. Derrick ◽  
Aliza Vardi ◽  
Roland Brlansky ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Virus Disease ◽  
Biological Activities ◽  
Cp Gene ◽  
Single Domain Antibodies ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) is the most important virus disease of citrus in the world. CTV causes death of trees on sour orange rootstock and/or stem pitting of scions regardless of rootstock which results in trees of low vigor, reduced yield with reduction in size and quality of fruit. The purpose of this project was to produce monoclonal antibodies (MABs) to CTV coat protein (CP), develop single domain antibodies (dAbs) or Fab fragments which neutralize the infection by binding to the virus, and to produce transformed plants which express the dAbs. The objectives of this research have been met and putative transgenic tobacco and citrus plants have been developed. These putative transgenic plants are presently undergoing evaluation to determine the level of dAbs expression and to determine their resistance to CTV. Additionally, the CTV genome has been sequenced and the CP gene of several biologically characterized CTV strains molecular characterized. This has indicated a correlation between CP sequence homology and biological activity, and the finding of DI RNAs associated with some CTV strains. Several MABs have been produced which enable broad spectrum identification of CTV strains while other MABs enable differentiation between mild and severe strains. The use of selected MAbs and determination of the CP gene sequence has enabled predictions of biological activities of unknown CTV isolates. The epitopes of two MABs, one reacting selectively with severe CTV strains and the other reacting with all strains, have been characterized at the molecular level.

scholarly journals Genetic Diversity and Phylogenetic Analysis of Citrus tristeza virus Isolates from Turkey

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Gözde Erkiş-Güngör ◽  
Bayram Çevik
Keyword(s):  
Phylogenetic Analysis ◽  
Citrus Tristeza Virus ◽  
Molecular Characteristics ◽  
Cloning And Sequencing ◽  
Phylogenetic Groups ◽  
The 1960S ◽  
Tristeza Virus ◽  
Virus Isolates ◽  
Stem Pitting ◽  
Citrus Tristeza

The presence of Citrus tristeza virus (CTV) in Turkey has been known since the 1960s and the virus was detected in all citrus growing regions of the country. Even though serological and biological characteristics of CTV have been studied since the 1980s, molecular characteristics of CTV isolates have not been studied to date in Turkey. In this study, molecular characteristics of 15 CTV isolates collected from different citrus growing regions of Turkey were determined by amplification, cloning, and sequencing of their major coat protein (CP) genes. The sequence analysis showed that the CP genes were highly conserved among Turkish isolates. However, isolates from different regions showed more genetic variation than isolates from the same region. Turkish isolates were clustered into three phylogenetic groups showing no association with geographical origins, host, or symptoms induced in indicator plants. Phylogenetic analysis of Turkish isolates with isolates from different citrus growing regions of the world including well-characterized type isolates of previously established strain specific groups revealed that some Turkish isolates were closely related to severe quick decline or stem pitting isolates. The results demonstrated that although CTV isolates from Turkey are considered biologically mild, majority of them contain severe components potentially causing quick decline or stem pitting.

INCIDENCE OF CITRUS TRISTEZA VIRUS, THE STEM PITTING ISOLATES IN THAILAND

2008 ◽  
pp. 51-56
Author(s):  
R. Sdoodee ◽  
P. Tothaum ◽  
J. Worapattamasri ◽  
P. Jantaradsamee ◽  
S. Patnantawech ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

scholarly journals In Situ Immunoassay (ISIA) of Field Grapefruit Trees Inoculated with Mild Isolates of Citrus tristeza virus Indicates Mixed Infections with Severe Isolates

Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 458-461 ◽  
Author(s):  
Youjian Lin ◽  
Phyllis A. Rundell ◽  
Charles A. Powell
Keyword(s):  
Monoclonal Antibodies ◽  
Immunosorbent Assay ◽  
Citrus Tristeza Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mixed Infections ◽  
The Cross ◽  
Tristeza Virus ◽  
Mild Isolate ◽  
Citrus Tristeza

Ten grapefruit trees that had been inoculated with a mild isolate of Citrus tristeza virus (CTV) and maintained in the field for 18 years were found in a previous study to be declining and infected with severe isolates of CTV, or symptomless and infected with mild isolates of CTV, using enzyme-linked immunosorbent assay (ELISA). They were assayed with an in situ immunoassay (ISIA) procedure using monoclonal antibodies 17G11 (reacts with most Florida isolates of CTV) and MCA13 (reacts with severe, but not Florida mild isolates of CTV). All the grapefruit trees were 17G11 positive by ELISA and ISIA. The five trees that showed moderate decline symptoms were MCA13 positive by ELISA and ISIA. The five symptomless trees were MCA13 negative by ELISA. However, four of the five symptomless trees were MCA13 positive by ISIA, which showed that ISIA with MCA13 had greater sensitivity in detecting severe CTV isolates than ELISA. These results suggested that the cross-protected grapefruit trees, regardless of symptoms, were infected with both mild and severe isolates of CTV.

scholarly journals Genetic Variation of Citrus Tristeza VirusIsolates from California and Spain: Evidence for Mixed Infections and Recombination

2001 ◽  
Vol 75 (17) ◽  
pp. 8054-8062 ◽  
Author(s):  
Luis Rubio ◽  
Marı́a Angeles Ayllón ◽  
Ping Kong ◽  
Andres Fernández ◽  
MaryLou Polek ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Citrus Tristeza Virus ◽  
Geographic Origin ◽  
Mixed Infections ◽  
Sequence Variants ◽  
Genomic Regions ◽  
Tristeza Virus ◽  
Major Sequence ◽  
Citrus Tristeza

ABSTRACT We examined the population structure and genetic variation of four genomic regions within and between 30 Citrus tristeza virus (CTV) isolates from Spain and California. Our analyses showed that most isolates contained a population of sequence variants, with one being predominant. Four isolates showed two major sequence variants in some genomic regions. The two major variants of three of these isolates showed very low nucleotide identity to each other but were very similar to those of other isolates, suggesting the possibility of mixed infections with two divergent isolates. Incongruencies of phylogenetic relationships in the different genomic regions and statistical analyses suggested that the genomes of some CTV sequence variants originated by recombination events between diverged sequence variants. No correlation was observed between geographic origin and nucleotide distance, and thus from a genetic view, the Spanish and Californian isolates analyzed here could be considered members of the same population.

Sign in / Sign up

Export Citation Format

Share Document