scholarly journals Evaluation of the Transmission of Different Field Sources of Citrus Tristeza Virus and the Separation of Different Genotypes by Single Brown Citrus Aphids

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 687-690
Author(s):  
Zhipeng Huang ◽  
Phyllis A. Rundell ◽  
Xiong Guan ◽  
Charles A. Powell

Four field sources of citrus tristeza virus (CTV) (Y3, Y6, Y7 and Y23) collected from grapefruit trees at groves in Fort Pierce, Florida, and isolate T36 were used to evaluate the transmission and separation of different virus genotypes by single brown citrus aphids (BrCA). Analysis of the field sources of CTV by inoculation to indicator plants, ELISA and RT-PCR showed that Y6 was a decline-inducing isolate and Y23 a nondecline-inducing isolate. Assays of genotype by RT-PCR indicated that Y6 contained the T36 genotype while Y23 contained the T30 genotype. Both Y3 and Y7 were a mixture of decline-inducing and nondecline-inducing CTV isolates and were a mixture of T36 and T30 genotypes. When Y6 and Y23 were the acquisition host for single BrCA, only the T36 or T30 genotypes, respectively, were detected by RT-PCR in `Mexican' Lime receptor plants. Only the T36 genotype was transmitted to receptor plants from infected Y3 and Y7 plants although these acquisition plants contained more than one genotype. No T3 or VT genotypes were detected in any acquisition or receptor plants. CTV genotype mixtures in the various field sources were separated by single BrCA transmission and that the T36 genotype in T36/T30 mixtures was more easily transmitted than the T30 genotype when the acquisition plant was `Duncan' grapefruit and the receptor plant was `Mexican' lime.

Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 693-693
Author(s):  
A. C. Cepeda-Nieto ◽  
H. A. Barrera-Saldaña

Citrus tristeza virus (CTV) causes one of the most important citrus diseases. CTV strains cause a wide range of symptoms in infected citrus worldwide. Although it has not yet affected Mexico's citrus industry, CTV constitutes a threat since one of its most efficient vectors, Toxoptera citricida, is migrating north from South America and is now in the Caribbean region. Efforts have been made to prevent spread of the virus, through early detection with serological methods (3). Use of the polymerase chain reaction (PCR), not yet a competitor of immunological methods in field diagnosis of CTV, offers a quick detection alternative. As a first step toward using PCR in early diagnosis and characterization of CTV, we searched for the CTV coat protein gene in experimentally infected leaves of Citrus aurantifolia grown at a government research station (INIFAP) at General Terán, NL. Researchers at General Terán had collected the isolates during a random sampling of orange orchards in the Gulf state of Veracruz. The original orange trees had no apparent symptoms and had been examined as a preventive measure. Several of the original orange trees were CTV positive in their initial tests with polyclonal antibody and in subsequent tests with CTV-specific monoclonal antibody MCA-13. Characteristic CTV-like particles had also been observed by electron microscopy. The only symptom induced in indicator plants was yellowing of the leaf veins. In our laboratory, reverse transcription of RNA from one of the indicator plants, coupled with PCR (RT-PCR) (1), was used to clone and sequence one of the isolates to confirm the CTV identification and establish PCR methods. Oligonucleotide primers were derived from published sequences, but unique restriction enzyme sites (EcoRI and XbaI) were added to their 5′ ends to facilitate cloning. To exclude artifacts, nucleotide sequences were obtained from both strands after cloning in M13 vectors. Although the expected RT-PCR product of 700 bp was obtained, an unexpected EcoRI site was found at position 678 of the coat protein gene. A phenylalanine residue was found at position 124, as in severe strains of CTV from various regions of the world (2). Similarities between our CT sequence (U32116) and those of other GenBank accessions are as follows: 91.17% for M76485; 90.14% for L12175; and 89.32% for S67800. References: (1) M. D. Jones and N. S. Foulkes. Nucleic Acids Res. 17:8387, 1989. (2) H. Pappu et al. Proc. Natl. Acad. Sci. USA. 90:3641, 1993. (3) C. Vela et al. J. Gen. Virol. 67:91, 1986.


Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1468-1468
Author(s):  
R. Abou Kubaa ◽  
K. Djelouah ◽  
A. M. D'Onghia ◽  
R. Addante ◽  
M. Jamal

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.


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

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.


VirusDisease ◽  
2018 ◽  
Vol 29 (3) ◽  
pp. 308-315 ◽  
Author(s):  
Kajal K. Biswas ◽  
Supratik Palchoudhury ◽  
Susheel K. Sharma ◽  
Bikram Saha ◽  
Shruti Godara ◽  
...  

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

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.


2000 ◽  
Vol 5 (1) ◽  
Author(s):  
M. L. P. N. Targon ◽  
M. A. Machado ◽  
A. A. Souza ◽  
G. W. Müller

2007 ◽  
Vol 120 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Edson Bertolini ◽  
Aranzazu Moreno ◽  
Nieves Capote ◽  
Antonio Olmos ◽  
Ana de Luis ◽  
...  

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 ◽  
...  

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).


2010 ◽  
Vol 100 (10) ◽  
pp. 1077-1088 ◽  
Author(s):  
Avijit Roy ◽  
G. Ananthakrishnan ◽  
John S. Hartung ◽  
R. H. Brlansky

The emerging diversity of Citrus tristeza virus (CTV) genotypes has complicated detection and diagnostic measures and prompted the search for new differentiation methods. To simplify the identification and differentiation of CTV genotypes, a multiplex reverse-transcription polymerase chain reaction (RT-PCR) technique for the screening of CTV isolates was developed. Variable regions within the open reading frame (ORF)-1a of diverse CTV genotypes were identified to develop first a simplex (S) and then a hexaplex (H) RT-PCR. CTV isolates have been grouped previously into five genotypes (namely, T3, T30, T36, VT, and B165) based on the nucleotide sequence comparisons and phylogenetic analyses. Nucleotide sequences from GenBank were used to design species and genotype-specific primers (GSPs). The GSPs were initially used for reliable detection of all CTV genotypes using S-RT-PCR. Furthermore, detection of all five recognized CTV genotypes was established using the H-RT-PCR. Six amplicons, one generic to all CTV isolates and one for each of the five recognized genotypes, were identified on the basis of their size and were confirmed by sequence analysis. In all, 175 CTV isolates from 29 citrus-growing countries were successfully analyzed by S- and H-RT-PCR. Of these, 97 isolates contained T36 genotypes, 95 contained T3 genotypes, 76 contained T30 genotypes, 71 contained VT genotypes, and 24 contained B165 genotype isolates. In total, 126 isolates contained mixed infections of 2 to 5 of the known CTV genotypes. Two of the CTV isolates could not be assigned to a known genotype. H-RT-PCR provides a sensitive, specific, reliable, and rapid way to screen for CTV genotypes compared with other methods for CTV genotype detection. Efficient identification of CTV genotypes will facilitate a better understanding of CTV isolates, including the possible interaction of different genotypes in causing or preventing diseases. The methods described can also be used in virus-free citrus propagation programs and in the development of CTV-resistant cultivars.


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