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1.
Plant Cell Rep ; 37(7): 967-980, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29564545

RESUMEN

KEY MESSAGE: Global gene expression analysis indicates host stress responses, mainly those mediated by SA, associated to the tolerance to sticky disease symptoms at pre-flowering stage in Carica papaya. Carica papaya plants develop the papaya sticky disease (PSD) as a result of the combined infection of papaya meleira virus (PMeV) and papaya meleira virus 2 (PMeV2), or PMeV complex. PSD symptoms appear only after C. papaya flowers. To understand the mechanisms involved in this phenomenon, the global gene expression patterns of PMeV complex-infected C. papaya at pre-and post-flowering stages were assessed by RNA-Seq. The result was 633 and 88 differentially expressed genes at pre- and post-flowering stages, respectively. At pre-flowering stage, genes related to stress and transport were up-regulated while metabolism-related genes were down-regulated. It was observed that induction of several salicylic acid (SA)-activated genes, including PR1, PR2, PR5, WRKY transcription factors, ROS and callose genes, suggesting SA signaling involvement in the delayed symptoms. In fact, pre-flowering C. papaya treated with exogenous SA showed a tendency to decrease the PMeV and PMeV2 loads when compared to control plants. However, pre-flowering C. papaya also accumulated transcripts encoding a NPR1-inhibitor (NPR1-I/NIM1-I) candidate, genes coding for UDP-glucosyltransferases (UGTs) and several genes involved with ethylene pathway, known to be negative regulators of SA signaling. At post-flowering, when PSD symptoms appeared, the down-regulation of PR-1 encoding gene and the induction of BSMT1 and JA metabolism-related genes were observed. Hence, SA signaling likely operates at the pre-flowering stage of PMeV complex-infected C. papaya inhibiting the development of PSD symptoms, but the induction of its negative regulators prevents the full-scale and long-lasting tolerance.


Asunto(s)
Carica/genética , Carica/virología , Enfermedades de las Plantas/virología , Proteínas de Plantas/genética , Carica/efectos de los fármacos , Flores , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Interacciones Huésped-Patógeno/fisiología , Enfermedades de las Plantas/genética , Hojas de la Planta/virología , Virus ARN/patogenicidad , ARN Mensajero , Reacción en Cadena en Tiempo Real de la Polimerasa , Reproducibilidad de los Resultados , Ácido Salicílico/metabolismo , Ácido Salicílico/farmacología , Análisis de Secuencia de ARN
2.
Viruses ; 7(4): 1853-70, 2015 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-25856636

RESUMEN

Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease, which is characterized by a spontaneous exudation of fluid and aqueous latex from the papaya fruit and leaves. The latex oxidizes after atmospheric exposure, resulting in a sticky feature on the fruit from which the name of the disease originates. PMeV is an isometric virus particle with a double-stranded RNA (dsRNA) genome of approximately 12 Kb. Unusual for a plant virus, PMeV particles are localized on and linked to the polymers present in the latex. The ability of the PMeV to inhabit such a hostile environment demonstrates an intriguing interaction of the virus with the papaya. A hypersensitivity response is triggered against PMeV infection, and there is a reduction in the proteolytic activity of papaya latex during sticky disease. In papaya leaf tissues, stress responsive proteins, mostly calreticulin and proteasome-related proteins, are up regulated and proteins related to metabolism are down-regulated. Additionally, PMeV modifies the transcription of several miRNAs involved in the modulation of genes related to the ubiquitin-proteasome system. Until now, no PMeV resistant papaya genotype has been identified and roguing is the only viral control strategy available. However, a single inoculation of papaya plants with PMeV dsRNA delayed the progress of viral infection.


Asunto(s)
Carica/virología , Enfermedades de las Plantas/virología , Virus de Plantas/genética , Virus de Plantas/fisiología , Virus ARN/genética , Virus ARN/fisiología , Carica/inmunología , Genoma Viral , Interacciones Huésped-Patógeno , Enfermedades de las Plantas/inmunología
3.
PLoS One ; 9(7): e103401, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25072834

RESUMEN

MicroRNAs are implicated in the response to biotic stresses. Papaya meleira virus (PMeV) is the causal agent of sticky disease, a commercially important pathology in papaya for which there are currently no resistant varieties. PMeV has a number of unusual features, such as residence in the laticifers of infected plants, and the response of the papaya to PMeV infection is not well understood. The protein levels of 20S proteasome subunits increase during PMeV infection, suggesting that proteolysis could be an important aspect of the plant defense response mechanism. To date, 10,598 plant microRNAs have been identified in the Plant miRNAs Database, but only two, miR162 and miR403, are from papaya. In this study, known plant microRNA sequences were used to search for potential microRNAs in the papaya genome. A total of 462 microRNAs, representing 72 microRNA families, were identified. The expression of 11 microRNAs, whose targets are involved in 20S and 26S proteasomal degradation and in other stress response pathways, was compared by real-time PCR in healthy and infected papaya leaf tissue. We found that the expression of miRNAs involved in proteasomal degradation increased in response to very low levels of PMeV titre and decreased as the viral titre increased. In contrast, miRNAs implicated in the plant response to biotic stress decreased their expression at very low level of PMeV and increased at high PMeV levels. Corroborating with this results, analysed target genes for this miRNAs had their expression modulated in a dependent manner. This study represents a comprehensive identification of conserved miRNAs inpapaya. The data presented here might help to complement the available molecular and genomic tools for the study of papaya. The differential expression of some miRNAs and identifying their target genes will be helpful for understanding the regulation and interaction of PMeV and papaya.


Asunto(s)
Carica/genética , MicroARNs/metabolismo , Enfermedades de las Plantas/virología , Virus de Plantas/fisiología , Secuencia de Bases , Carica/metabolismo , Bases de Datos Genéticas , Etiquetas de Secuencia Expresada , Regulación de la Expresión Génica de las Plantas , Genoma de Planta , MicroARNs/clasificación , Filogenia , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Complejo de la Endopetidasa Proteasomal/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Alineación de Secuencia , Carga Viral
4.
J Virol Methods ; 180(1-2): 11-7, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22193169

RESUMEN

Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease. This study describes two methods for molecular diagnosis of PMeV using conventional and real-time PCR. These methods were shown to be more efficient than current methods of viral detection using extraction of PMeV dsRNA and observation of symptoms in the field. The methods described here were used to evaluate the effect of inoculation of papaya plants with purified PMeV dsRNA on the progress of PMeV infection. A single inoculation with PMeV dsRNA was observed to delay the progress of the virus infection by several weeks. The possibility of vertical transmission of PMeV was also investigated. No evidence was found for PMeV transmission through seeds collected from diseased fruit. The implications of these results for the epidemiology of PMeV and the management of papaya sticky disease are discussed.


Asunto(s)
Carica/virología , Enfermedades de las Plantas/virología , Hojas de la Planta/virología , Virus de Plantas/genética , Virus ARN/genética , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Virus de Plantas/aislamiento & purificación , Virus de Plantas/patogenicidad , Virus ARN/patogenicidad , ARN Bicatenario/genética
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