scholarly journals Population Dynamics of a Florida Citrus tristeza virus Isolate and Aphid-Transmitted Subisolates: Identification of Three Genotypic Groups and Recombinants After Aphid Transmission

2009 ◽  
Vol 99 (11) ◽  
pp. 1297-1306 ◽  
Author(s):  
Avijit Roy ◽  
R. H. Brlansky
Keyword(s):  
Population Dynamics ◽  
Citrus Tristeza Virus ◽  
Pcr Amplification ◽  
Aphid Transmission ◽  
Rt Pcr ◽  
Reading Frame ◽  
Florida Citrus ◽  
Tristeza Virus ◽  
Overlapping Region ◽  
Citrus Tristeza

Tristeza is an important citrus disease affecting the viability and productivity of citrus worldwide. The causal agent, Citrus tristeza virus (CTV), usually occurs as a mixture of genotypes in nature, with one of the genotypes often dominating the population. CTV has a monopartite, positive-sense RNA genome of ≈19.3 kb and exhibits over 30% diversity in the 5′ half and less than 10% in the 3′ half among different genotypes. A Florida CTV isolate, FS627, was selected for this study. Isolate FS627 was analyzed by reverse-transcription polymerase chain reaction (RT-PCR) using primers to three regions: 788-bp region in the 5′ (697 to 1,484 nucleotides), open reading frame (ORF)1a, 696 or 718 bp from the overlapping region of the RdRp (ORF1b) and p33 (ORF2) gene, and a 672-bp major coat protein gene (ORF7) in the 3′ end of the CTV genome. The presence of T36, T30, and VT genotypes in isolate FS627 was confirmed utilizing the genotype specific overlapping region of RdRp primer pairs for RT-PCR amplification followed by cloning and sequence analysis. Analysis of single-strand conformational polymorphisms and sequences of RT-PCR-amplified products of the above regions were used to determine the presence of genotypes in both the parent and aphid-transmitted (AT) subisolates. Although the parent isolate had T36 as the major genotype, T30 was the major genotype in most of the AT subisolates. Some intermediate genotypes were detected that differed from the parental or AT subisolates. These intermediate genotypes were considered to be recombinants of the T30 and T36 genotypes and also were observed in the second level of AT subisolates generated from the of first-level AT subisolates of CTV-FS627. This work provides advance information on the population dynamics in CTV mixtures and the generation of virus recombinants after aphid transmission.

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.

scholarly journals Comportamento de híbridos de citros em relação à infecção natural pelo Citrus tristeza virus e à presença de sintomas de descamamento eruptivo

2014 ◽  
Vol 36 (3) ◽  
pp. 735-741 ◽  
Author(s):  
Almir Santos Rodrigues ◽  
Cristiane de Jesus Barbosa ◽  
Walter dos Santos Soares Filho ◽  
Juliana Freitas-Astúa
Keyword(s):  
Citrus Tristeza Virus ◽  
Rt Pcr ◽  
Tristeza Virus ◽  
Citrus Tristeza

O Programa de Melhoramento Genético de Citros da Embrapa Mandioca e Fruticultura vem gerando híbridos para utilização como porta-enxertos, que necessitam ser avaliados em relação ao comportamento frente à infecção natural por isolados locais de Citrus tristeza virus (CTV) e à presença de sintomas de descamamento eruptivo (BahiaBarkScaling disease - BBS). Este trabalho apresenta resultados da avaliação do comportamento de 141 híbridos (sob a forma de pés-francos ou enxertados) estabelecidos na área experimental da Embrapa Mandioca e Fruticultura, no Recôncavo Sul da Bahia. Foram avaliadas a presença e a severidade de sintomas de caneluras e descamamento por meio de escala de notas. Para detectar a presença do CTV, foi utilizado o método sorológico de ELISA indireto e RT-PCR. Os híbridos avaliados foram classificados como imunes, tolerantes e intolerantes ao CTV. A maioria dos híbridos que apresentaram sintomas de BBS tem uma tangerineira como parental.

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 Molecular Variability of the 5′- and 3′-Terminal Regions of Citrus Tristeza Virus RNA

1998 ◽  
Vol 88 (7) ◽  
pp. 685-691 ◽  
Author(s):  
C. López ◽  
M. A. Ayllón ◽  
J. Navas-Castillo ◽  
J. Guerri ◽  
P. Moreno ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Biological Properties ◽  
Terminal Region ◽  
Cdna Clones ◽  
Reading Frame ◽  
Group Iii ◽  
Sequence Identity ◽  
Virus Rna ◽  
Tristeza Virus ◽  
Citrus Tristeza

Isolates of citrus tristeza virus (CTV) differ widely in their biological properties. These properties may depend on the structure of viral RNA populations comprising the different isolates. As a first approach to study the molecular basis of the biological variability, we have compared the sequences of multiple cDNA clones of the two terminal regions of the RNA from different CTV isolates. The polymorphism of the 5′ untranslated region (UTR) allowed the classification of the sequences into three groups, with intragroup sequence identity higher than 88% and intergroup sequence identity as low as 44%. The variability of an open reading frame (ORF) 1a segment adjacent to the 5′ UTR supports the same grouping. Some CTV isolates contained sequences of more than one group. Most sequences from Spanish isolates belonged to group III, whereas a Japanese isolate was composed mostly of sequences of groups I and II. The mildest isolates contained only sequences of group III, whereas the most severe isolates also contained sequences of groups I, II, or both. The most stable secondary structure predicted for the 5′ UTR was composed of two stem-loops and remained essentially unchanged as a result of compensatory mutations in the stems and accommodation of most of the variability in the loops. In contrast to the 5′-terminal region, the variability of the 3′-terminal region of CTV RNA was very much restricted, with nucleotide identity values higher than 90%. The presence of a conserved putative “zinc-finger” domain adjacent to a basic region in p23, the predicted product of ORF 11, suggests that this protein might act as a regulatory factor during virus replication.

scholarly journals The Haplotype Distribution of Two Genes of Citrus Tristeza Virus Is Altered after Host Change or Aphid Transmission

Virology ◽  
1999 ◽  
Vol 255 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Marı́a A. Ayllón ◽  
Luis Rubio ◽  
Andrés Moya ◽  
José Guerri ◽  
Pedro Moreno
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Haplotype Distribution ◽  
Tristeza Virus ◽  
Citrus Tristeza

scholarly journals Prevalence of Severe Strains of Citrus Tristeza Virus in Florida Citrus Nurseries

HortScience ◽  
1993 ◽  
Vol 28 (7) ◽  
pp. 699-700 ◽  
Author(s):  
Charles A. Powell ◽  
Robert R. Pelosi
Keyword(s):  
Citrus Sinensis ◽  
Citrus Tristeza Virus ◽  
Severe Strain ◽  
Florida Citrus ◽  
Tristeza Virus ◽  
Citrus Tristeza

Sixty-eight percent of the `Pineapple', 52% of the `Navel', 46% of the `Valencia', 38% of the `Hamlin', and 0% of the `Ambersweet' orange [Citrus sinensis (L.) Osh.] trees in five Florida citrus nurseries were infected with severe strains of citrus tristeza virus (CTV), as demonstrated by reaction with a monoclinal antibody specific for severe strains of the virus. Severe strains of CTV infected 4%, 46%, 76%, 30%, and 48% of the trees at each of the five nurseries, respectively, indicating a considerable difference in severe strain prevalence among the nurseries. Thirty-five percent of the trees in the scion blocks (budwood source) of the nurseries also contained severe strains of CTV.

scholarly journals Prevalence of Citrus Tristeza Virus in Florida Citrus Nurseries and Scion Groves

HortScience ◽  
2003 ◽  
Vol 38 (2) ◽  
pp. 244-245 ◽  
Author(s):  
Charles A. Powell ◽  
Robert R. Pelosi ◽  
Phyllis A. Rundell
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Enzyme Linked Immunosorbent Assay ◽  
Nursery Trees ◽  
Florida Citrus ◽  
High Level ◽  
Individual Trees ◽  
Tristeza Virus ◽  
Composite Samples ◽  
Citrus Tristeza

None of 4190 sweet orange [Citrus sinensis (L.) Osb.] nursery trees of `Hamlin', `Midsweet', `Navel', and `Valencia' sampled from five Florida citrus nurseries were infected with a decline-inducing isolate of citrus tristeza virus (CTV) as judged by enzyme-linked immunosorbent assay (ELISA) using isolate-specific monoclonal antibodies. Two of the nurseries had a relatively high level of infection (37% to 100% of composite samples containing tissue from 10 trees) with nondecline-inducing (mild) isolates of CTV, depending on the cultivar. Three of the nurseries had a lower incidence of mild CTV (0% to 22% of 10 tree composite samples). No nursery was CTV-free. ELISA of individual trees used as budwood sources by the nurseries revealed that one tree out of 260 tested contained decline-inducing CTV, and 83 contained mild CTV. These results suggest that the budwood certification program adopted in 1997 has virtually eliminated decline-inducing CTV from commercial budwood supplies.

scholarly journals Identificação de isolados de Citrus tristeza virus (CTV) protetivos para Citrus sinensis (L.) Osbeck

2018 ◽  
Vol 44 (1) ◽  
pp. 17-22
Author(s):  
Ana Paula Gonçalves ◽  
Karina Silva dos Santos ◽  
Camila de Cassia Silva ◽  
Tanara Garcia de Novaes ◽  
Rúbia de Oliveira Molina
Keyword(s):  
Citrus Sinensis ◽  
Citrus Tristeza Virus ◽  
Rt Pcr ◽  
Tristeza Virus ◽  
Citrus Tristeza

RESUMO O Citrus tristeza virus (CTV) causa significativas perdas na produtividade de laranja doce [Citrus sinensis (L.) Osbeck] e seu controle tem sido realizado principalmente com a premunização. O trabalho teve como objetivo analisar a variabilidade de isolados fortes e fracos de CTV provenientes de plantas de citros inoculadas e mantidas em casa de vegetação e amostras de campo, coletadas em pomar comercial situado no município de Rolândia, PR. Para a determinação da variabilidade e diversidade genética dos isolados foi realizada avaliação dos sintomas e empregadas as técnicas de RT– PCR e RFLP, utilizando os oligonucleotídeos específicos HCP1/HCP2 e posterior sequenciamento dos fragmentos amplificados. Na avaliação de canelura, os isolados mantidos em casa de vegetação induziram sintomas leves, com exceção do isolado severo Capão Bonito. Os sintomas mais severos ocorreram em amostras situadas no campo. De acordo com as análises multivariadas os isolados de CTV tendem a se agrupar conforme a severidade dos sintomas e condições ambientais as quais foram expostas formando agrupamentos distintos entre amostras provenientes do campo e casa de vegetação. O dendrograma gerado a partir do sequenciamento dos isolados e as análises multivariadas revelaram que o isolado proveniente da amostra “Forte Arapongas” apresentou maior similaridade com o controle padrão forte proveniente de Capão Bonito. Os isolados identificados como fracos e provenientes das amostras Pêra IAC e Rolândia 5 apresentaram maior similaridade. Pode-se aferir que plantas hospedeiras mantidas em campo possuem maior variabilidade de isolados.

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