Sintomas de "exocortis" em limoeiro cravo

Moreira, Silvino Intra

doi:10.1590/s0006-87051955000100033

Cited by 6 publications

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“…Later, this disease was demonstrated to be graft-transmissible (Benton et al, 1949(Benton et al, , 1950 and incited by CEVd (Semancik and Weathers, 1972). Similar disorders were also reported as scaly butt of trifoliate orange in Australia (Benton et al, 1949) and in Rangpur lime (Citrus limonia Osbeck) in Brazil (Moreira, 1955(Moreira, , 1959. HSVd variants include CVd-IIa, CVd-IIb, and CVd-IIc (Foissac and Duran-Vila, 2000;Palacio-Bielsa et al, 2004;Semancik, 1999a, 1999b;Semancik et al, 1988aSemancik et al, , 1988b.…”

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Molecular Detection and Prevalence of Citrus Viroids in Texas

Kunta¹,

Graça²,

Skaria³

2007

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Viroids are graft- or mechanically transmissible agents, disseminated through budding. Biological indexing of commercially important citrus cultivars grown in the Lower Rio Grande Valley of Texas showed that many are infected with citrus viroids. Most of these trees carried more than one viroid. In most cases, the infected trees are asymptomatic carriers because sour orange, the predominant rootstock used in Texas, does not show symptoms of viroid infection. Detection of viroids through biological indexing on sensitive indicator plants followed by sequential polyacrylamide gel electrophoresis (sPAGE) is the gold standard but is time-consuming and requires plants to be kept at optimum conditions. A conditional use of reverse transcriptase–polymerase chain reaction (RT-PCR) provides an efficient and alternative detection of viroids for use in the Texas virus-free citrus budwood certification program. RT-PCR could be useful in Texas to help expedite the evaluation for the presence of viroids before conducting the final biologic indexing. Using RT-PCR, we could detect, clone, and sequence full-length viroids of Citrus exocortis viroid (CEVd), Hop stunt viroid (HSVd) (both cachexia and noncachexia variants), Citrus viroid-III (Citrus dwarfing viroid), and Citrus viroid-IV (Citrus bark cracking viroid) from a collection of viroid-inoculated grapefruit plants. The source plants were previously shown to be viroid-infected by biological indexing on Etrog citron plants. Based on our results, RT-PCR can be a conditional substitute for biological indexing of mother trees in foundation blocks and shoot tip-grafted trees in the virus-free budwood program. A positive RT-PCR result has a serendipitous value because those trees can be discarded from the pool before expensive biological indexing.

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confidence: 85%

Molecular Detection and Prevalence of Citrus Viroids in Texas

Kunta¹,

Graça²,

Skaria³

2007

horts

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“…Quase simultaneamente, demonstrou-se que uma alteração similar, conhecida como "scally butt" na Austrália desde a década de 1930, era transmissível por enxertia (Benton et al, 1949). Hoje se sabe que essas duas enfermidades, além de uma terceira detectada nos EUA e Brasil, ao serem enxertadas em determinadas variedades de copa sobre limoeiro Cravo (Citrus limonia Osbeck), e que foi denominada "enfermidade do limão Cravo" (Moreira, 1955(Moreira, , 1959, são a mesma doença (Duran-Vila, 1989a). Somente no início da década de 1970, Semancik & Wheathers (1972a demonstraram que o agente causal da exocorte, até então atribuída a um possível vírus, na verdade era um viroide, denoninado Citrus exocortis viroid (CEVd).…”

Section: Históricounclassified

“…O limão 'Cravo' utilizado como porta-enxerto, é a única espécie comercial descrita como sintomática à exocorte e xiloporose (Moreira, 1955;1959). Entretanto, a relação causa-efeito somente foi confirmada para o HSVd (Reanwarakorn & Semancik, 1999b) e pouco se sabe sobre a reação desta espécie à infecção por outros viroides dos citros (Rodrigues et al, 1999).…”

Section: Transmissão Sintomas E Danosunclassified

“…Semancik e L.G. Weathers demonstraram que a doença da exocorte dos citros, conhecida desde meados do século 20 como de provável etiologia viral (Fawcet & Klotz, 1948;Benton et al, 1949;Moreira, 1955Moreira, , 1959, também era causada por um viroide: denominado de Citrus exocortis viroid (CEVd) (Semancik & Weathers, 1972a). A sequência genômica do CEVd foi elucidada somente 10 anos mais tarde (Gross et al, 1982;Visvader & Symons, 1985;Visvader et al, 1982), sendo que hoje em dia, um enorme número de variantes do CEVd têm suas sequências publicadas e disponibilizadas em bancos internacionais de dados.…”

Section: Citrus Exocortis Viroid (Cevd)unclassified

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Viroides em Citros

Eiras

Silva

Stuchi

et al. 2009

Trop. plant pathol.

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RESUMOOs viroides são os menores fitopatógenos conhecidos. Constituídos por uma molécula de RNA de fita simples, circular, que não é encapsidada e não codifica proteínas, são capazes de se replicar de maneira autônoma nas células do hospedeiro. Os viroides de citros pertencem à família Pospiviroidae (cujos membros apresentam uma região central conservada, replicam-se no núcleo das células hospedeiras e não apresentam atividade ribozimática) com cinco espécies: Citrus exocortis viroid, CEVd (Pospiviroid), Hop stunt viroid, HSVd (Hostuviroid), Citrus bark cracking viroid, CBCVd (Cocadviroid) e Citrus bent leaf viroid, CBLVd e Citrus dwarfing viroid, CDVd (Apscaviroid). Além disso, Citrus viroid original source (CVd-OS) e mais recentemente, Citrus viroid V (CVd-V) foram propostas como espécies tentativas do gênero Apscaviroid. Os viroides de citros são transmitidos via enxertia e disseminados principalmente pela propagação de material contaminado. Sabe-se que os viroides de citros infectam praticamente todas as espécies do gênero Citrus e afins. Porém, há somente duas doenças importantes descritas em citros, induzidas por viroides: (i) a exocorte; (ii) e a xiloporose (ou cachexia). Apesar dos viroides induzirem sintomas severos, ou simplesmente afetarem o tamanho das árvores, muitas espécies de citros são assintomáticas, sendo o controle baseado em medidas preventivas, como utilização de gemas livres de viroides aliadas a métodos confiáveis de indexação. A proposta desta revisão é apresentar ao leitor os recentes avanços nas pesquisas com viroides de citros, principalmente na taxonomia, distribuição geográfica, métodos de detecção, limpeza e indexação, epidemiologia e controle, além do histórico e importância desses patógenos para a citricultura mundial. Palavras-chave: Citrus exocortis, Hop stunt, Pospiviroid, Apscaviroid, Cocadviroid, Hostuviroid, Exocorte, Xiloporose. ABSTRACT Viroids in CitrusViroids are the smallest known plant pathogens consisting of a non-encapsidated, circular, single-stranded RNA that replicate autonomously in their host plants. Viroids are classified into two families (Pospiviroidae and Avsunviroidae). All citrus viroids belong to the Pospiviroidae family (species that present a central conserved region, replicate in the nucleus of infected cells and lack of ribozyme activity) with five citrus viroid species: Citrus exocortis viroid, CEVd (Pospiviroid), Hop stunt viroid, HSVd (Hostuviroid), Citrus bark cracking viroid, CBCVd (Cocadviroid) and Citrus bent leaf viroid, CBLVd and Citrus dwarfing viroid, CDVd (Apscaviroid). In addition, Citrus viroid original source (CVd-OS) and, more recently, Citrus viroid V (CVd-V) have been proposed as tentative species of the genus Apscaviroid. Citrus viroids are graft-transmitted and their dissemination occurs mainly by propagation of contaminated material. It is known that they have a broad host range, infecting species of citrus and plants of citrus-related genera. Two important diseases in citrus are viroid-induced: (i) exocortis; (ii) and cachexia. ...

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Citrus Variegated Chlorosis: an Overview of 30 Years of Research and Disease Management

Coletta-Filho

Castillo

Laranjeira

et al. 2020

Trop. plant pathol.

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The emergence of citrus variegated chlorosis (CVC) disease had dramatic consequences to the citrus industry in Brazil. First reported in São Paulo State in 1987, this disease affected approximately 100 million sweet orange trees in the region 20 years later. However, current estimates indicate that the number of diseased trees has been reduced 25-fold since 2009. In this review we summarize research on CVC since its emergence, focusing on work that has contributed to the observed success in managing this disease in the field. Knowledge that CVC is caused by a bacterium (Xylella fastidiosa-now classified as X. fastidiosa subsp. pauca) that is transmited by infected plant material (grafting and nursery plant) and insect vectors, the citrus nursery production system switched in 2003 to a certification program in which plants are grown in insect proof screen-houses and routinely monitored for X. fastidiosa infection. Research triggered by the genome sequencing of a CVC isolate in 2000, the first plant pathogenic bacterium to have its complete genome sequenced, integrated molecular tools and approaches into research aimed at understanding the biology of this pathogen. Ultimately, the challenges imposed by CVC led to significant improvements in the scientific and technical knowledge linked to sweet orange production, and to the development of a more sustainable and resilient citrus industry in Brazil.

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Sintomas de "exocortis" em limoeiro cravo

Cited by 6 publications

References 0 publications

Molecular Detection and Prevalence of Citrus Viroids in Texas

Molecular Detection and Prevalence of Citrus Viroids in Texas

Viroides em Citros

Citrus Variegated Chlorosis: an Overview of 30 Years of Research and Disease Management

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