RESUMEN
Cowpea mild mottle virus (CPMMV) is a flexuous filamentous virus that belongs to the genus Carlavirus (family Betaflexiviridae). The CPMMV genome contains six open reading frames (ORFs), among which the triple gene block (TGB), encoded by ORFs 2 to 4, has been reported to encode movement proteins for different viruses. The subcellular localization of the TGB proteins of CPMMV isolate CPMMV:BR:MG:09:2 was analysed by transient expression of each protein fused to a fluorophore. Overall, the accumulation pattern and interactions among CPMMV TGB proteins (TGBp) were similar to those of their counterparts from the potex-like group. Considering these similarities, we evaluated the potential interactions between the TGB proteins of CPMMV and of potato virus X, which could complement cell-to-cell movement. The TGBp2 and TGBp3 of PVX had an effect on CPMMV TGBp1, directing it to the plasmodesmata, but the reverse was not true.
Asunto(s)
Carlavirus , Flexiviridae , Potexvirus , Nicotiana , Proteínas Virales/genética , Proteínas Virales/metabolismo , Carlavirus/genética , Potexvirus/genética , Flexiviridae/genéticaRESUMEN
Coffee ringspot virus (CoRSV) a member of the proposed genus "Dichorhavirus", was surveyed on commercial and research farms spanning an area responsible for the majority of Coffea arabica production in Brazil. Virus-infected plants were found at one hundred percent of locations (n = 45) sampled. All cultivars, regardless of cherry color, were found to serve as hosts, suggesting that there is limited resistance in commercially employed germplasm. Reverse transcription PCR analysis revealed that the virus is contained within symptomatic lesions, with little systemic spread throughout leaves. Phylogenetic analysis based on the ORF1 (nucleocapsid) gene identified a strong geo-spatial relationship among isolates, which clustered into three clades. Despite low genetic diversity among isolates, variation in symptom expression was observed in the experimental host Chenopodium quinoa. Our analyses support the hypothesis that the spread of CoRSV is constrained by the clonal expansion of thelytokous populations of Brevipalpus phoenicis. The widespread occurrence of this virus suggests that it is much more prevalent than previously thought.
Asunto(s)
Coffea/virología , Enfermedades de las Plantas/virología , Virus de Plantas/aislamiento & purificación , Rhabdoviridae/aislamiento & purificación , Animales , Brasil , Análisis por Conglomerados , Variación Genética , Datos de Secuencia Molecular , Filogeografía , Virus de Plantas/clasificación , Virus de Plantas/genética , ARN Viral/análisis , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rhabdoviridae/clasificación , Rhabdoviridae/genética , Análisis de Secuencia de ADN , Homología de SecuenciaRESUMEN
The emergence of viruses in Coffee (Coffea arabica and Coffea canephora), the most widely traded agricultural commodity in the world, is of critical concern. The RNA1 (6552nt) of Coffee ringspot virus is organized into five open reading frames (ORFs) capable of encoding the viral nucleocapsid (ORF1p), phosphoprotein (ORF2p), putative cell-to-cell movement protein (ORF3p), matrix protein (ORF4p) and glycoprotein (ORF5p). Each ORF is separated by a conserved intergenic junction. RNA2 (5945nt), which completes the bipartite genome, encodes a single protein (ORF6p) with homology to RNA-dependent RNA polymerases. Phylogenetic analysis of L protein sequences firmly establishes CoRSV as a member of the recently proposed Dichorhavirus genus. Predictive algorithms, in planta protein expression, and a yeast-based nuclear import assay were used to determine the nucleophillic character of five CoRSV proteins. Finally, the temperature-dependent ability of CoRSV to establish systemic infections in an initially local lesion host was quantified.
Asunto(s)
Coffea/virología , Enfermedades de las Plantas/virología , Rhabdoviridae/aislamiento & purificación , Secuencia de Aminoácidos , Secuencia de Bases , Coffea/química , Genoma Viral , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Filogenia , Rhabdoviridae/química , Rhabdoviridae/clasificación , Rhabdoviridae/genética , Semillas/química , Semillas/virología , Alineación de Secuencia , Proteínas Virales/química , Proteínas Virales/genéticaRESUMEN
Population diversity was evaluated in strains of Staphylococcus aureus isolated from bovine mastitis in Brazilian dairy herds by PCR-RFLP and sequencing of the 3'-terminal portion of the coagulase gene, and the susceptibility of strains to antimicrobials. The results showed great diversity in S. aureus population studied and the existence of predominant clones that account for most infections. No associations between the predominant types observed in the PCR-RFLP and the forms of presentation of the mastitis or to any of the different patterns of antimicrobial resistance were observed.
Asunto(s)
Industria Lechera , Variación Genética , Mastitis Bovina/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus/genética , Animales , Brasil/epidemiología , Bovinos , Femenino , Regulación Bacteriana de la Expresión Génica , Genotipo , Mastitis Bovina/epidemiología , Filogenia , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/clasificaciónRESUMEN
Productivity of 'yellow' passion fruit (Passiflora edulis Sims. f. flavicarpa O. Deg.) is reduced by infection with Cowpea aphid-borne mosaic virus (CABMV). We examined resistance in 72 yellow passion fruit plants grown from open-pollinated commercial seed. Plants were mechanically inoculated with CABMV virus and maintained in the field in order to select contrasting genotypes for resistance. Isolates were obtained from symptomatic leaves of yellow passion fruit plants from field production in Livramento de Nossa Senhora, Bahia state and were characterized by sequencing the viral coat protein gene. Severity of leaf symptoms of the disease, evaluated through a global leaf disease index, was measured during the eighth month of growth. Morpho-agronomic variables of fruit were evaluated from months 10 to 12. Significant linear regressions between the quantification of the leaf symptoms and the morpho-agronomic characteristics related to productivity were detected (5.17% Asunto(s)
Comovirus/patogenicidad
, Passiflora/genética
, Passiflora/virología
, Enfermedades de las Plantas/genética
, Enfermedades de las Plantas/virología
, Brasil
, Comovirus/genética
, Predisposición Genética a la Enfermedad/genética
, Passiflora/crecimiento & desarrollo
, Hojas de la Planta/virología