Revista De La Facultad De Agronomia De La Universidad Del Zulia, 2016
La transmision de virus fitopatogenos por coleopteros fue considerada como un proceso mecanico en... more La transmision de virus fitopatogenos por coleopteros fue considerada como un proceso mecanico en el cual los virus que llevaban estos insectos en su aparato bucal o en los regurgitados los depositaban en las heridas ocasionadas al momento de la alimentacion. Trabajos recientes han demostrado que este proceso es muy especifico y biologicamente complejo, y no simplemente un problema de contaminacion de las partes bucales del vector. En este articulo se revisan los aspectos fundamentales del proceso de transmision de virus de plantas por coleopteros. Estos virus alcanzan una alta concentracion en los tejidos infectados, son relativamente estables, tienen particulas poliedricas de 25-30 nm de diametro, contienen ARN de cadena sencilla, son transmitidos facilmente por inoculacion mecanica y tienen una alta antigenicidad. Las especies de virus transmitidas por coleopteros pertenecen a los generos Bromovirus, Carmovirus, Comovirus, Machlomovirus, Sobemovirus y Tymovirus, mientras que las ...
El ají (Capsicum spp.) tiene amplio uso en el arte culinario por su fragancia y sabor típico, hac... more El ají (Capsicum spp.) tiene amplio uso en el arte culinario por su fragancia y sabor típico, haciéndolo en muchos casos más preferido que el pimentón. En Venezuela, su explotación se ha incrementado paulatinamente; sin embargo, es afectado por diversos patógenos, entre ellos los virus. El virus de la marchitez manchada del tomate (Tomato spotted wilt virus, TSWV; Tospovirus, Bunyaviridae) es considerado un virus muy peligroso, pudiendo causar pérdidas cuantiosas en solanáceas (25-100 %); infecta más de 1.000 especies de plantas y es cosmopolita. Recientemente, el TSWV fue detectado infectando gerbera (Gerbera jamesonii) en viveros en los Altos Mirandinos (Miranda), pudiendo estar diseminado en otros cultivos y malezas. Por esta razón, el objetivo de este trabajo fue determinar la respuesta de los cultivares de ají Llanerón y Chirel al TSWV. De cada cultivar se inocularon mecánicamente 25 plantas, en presencia de buffer fosfato 0,1 M, pH 8 + 1% de sulfito de sodio (relación 1:5, p/v...
ABSTRACT Yardlong bean [Vigna unguiculata subsp. sesquipedalis (L.) Verdc.] is a distinctive subs... more ABSTRACT Yardlong bean [Vigna unguiculata subsp. sesquipedalis (L.) Verdc.] is a distinctive subspecies of cowpea, with apparent origin in East Asia. Yardlong bean is characterized by extremely long and thin pods, and is considered one of the top ten Asian vegetables. It is now grown extensively in Asia, Europe, Oceania and Americas. In 2012, yardlong bean plants showing severe yellowing were found in an experimental plot at the Agronomy Faculty, UCV, in Aragua State, Venezuela. The observed incidence of foliar yellowing symptoms, resembling those associated with the infection of a bromovirus, was 30%. The field samples with virus-like symptoms of yellowing were collected for further studies. Previously, we reported the presence of Cowpea mild mottle virus (CPMMV), a carlavirus with filamentous particles, in yard long bean in the country (Brito et al., 2012), but electron microscope observations using the leaf-dip method excluded CPMMV, since symptomatic leaves contained icosahedral virus-like particles, ca. 26-28 nm in diameter. Leaf extracts from field samples were mechanically inoculated onto V. unguiculata cv. Tuy, Vigna. radiata, Phaseolus vulgaris L. cv. Tacarigua, Chenopodium quinoa Willd., C. amaranticolor Coste et A. Reyn, Gomphrena globosa L. and Glycine max (L.) Merr. All the seven mechanically inoculated plant species were found susceptible to the virus. Among these, C. amaranticolor, C. quinoa and G. globosa developed chlorotic local lesions 10-14 days post inoculation (dpi), while V. radiata developed local necrotic lesions on inoculated leaves. Seedlings of V. unguiculata and G. max were found systemically infected and showed mottle and mosaic symptoms on upper non-inoculated leaves at 7 dpi. Extensive severe systemic chlorosis was developed in cowpea after 15 dpi. A virus isolate was propagated in V. unguiculata cv. Tuy, grown under greenhouse conditions, purified (de Carvalho et al., 2013), and tested by Western blot using polyclonal antisera specific to Cowpea mosaic virus (CPMV), Southern bean mosaic virus (SBMV), Broad bean mottle virus (BBMV), Cucumber mosaic virus (CMV) and Cowpea chlorotic mottle virus (CCMV). A conspicuous immunoreactive band with an approximate size of 19 kDa was obtained in purified virus sample against BBMV and CCMV antisera. Total RNA was extracted from 20 symptomatic plants and from purified virions, and tested by RT-PCR using degenerate primers Ilar1F5 (GCNGGWTGYGGDAARWCNAC) and Ilar1R7 (AMDGGWAYYTGYTNYGTRTCACC), specific to the detection of members of the genus Ilarvirus and family Bromoviridae (Untiveros et al., 2010). A PCR fragment of the expected size (ca. 300 bp) was amplified for all samples. Two amplicons were sequenced and the identical (100%) consensus sequences submitted to the GenBank database (NCBI, USA), with the accession numbers KJ810515 (from field yardlong bean) and KJ810516 (from purified virions). The deduced amino acid sequence contained 97 residues encoding part of the viral methyltransferase which was 93% identical to that of a CCMV methyltransferase (AAN37635.1). A nucleotide BLAST analysis of the sequence revealed 85% identity with CCMV strain T (AF325739). The level of sequence similarity with CCMV suggested that the virus from yardlong bean may be a distinct strain of this species. Phylogenetic analysis of the putative methyltransferase gene demonstrated that CCMV yardlong bean clustered separately form the known strains of CCMV. Because chrysomelids are known vectors of bromoviruses, virus-free Andrector ruficornis Olivier, A. arcuatus Olivier and Ledesmodina auricollis Lèfevre adults were exposed to symptomatic cowpea leaves for a 48-hour acquisition access period and then cage-confined with 10 healthy V. unguiculata cv. Tuy and P.vulgaris cv. Tacarigua each for a 48-hour inoculation access period. Symptoms were reproduced in all tested plants after 21-day period and CCMV infection was confirmed by RT-PCR assay. To our knowledge, this is the first evidence of the presence of CCMV in yardlong bean, and the first report of CCMV transmission by chrysomelid beetle L. auricollis. This is an important information for the Venezuelan cowpea’s market as CCMV-infected yardlong bean plants could act as virus source for secondary spread by beetle vectors. References: de Carvalho et al. Tropical Plant Pathology 38(1): 49-54, 2013., Untiveros et al., J. Virol. Methods 165: 97-104, 2010., Brito et al., Viruses 4: 3804-3811, 2012.
ABSTRACT Seeds as a source of Cucumber mosaic virus (CMV) have been reported in several species o... more ABSTRACT Seeds as a source of Cucumber mosaic virus (CMV) have been reported in several species of plants, but in the literature no results of this type of transmission were found in canna. For this reason, it was considered of interest this research in order to determine if CMV is transmitted directly through the seed of canna (Canna indica). To do this, were collected 254 seeds from infected plants and sown individually in plastic containers containing sterile substrate. Evaluations were performed for a month under greenhouse conditions. Sap from new plants showing viral symptoms was extracted and used to mechanically inoculate cotyledonary leaves of healthy cowpea (Vigna unguiculata) cv Tuy plants in which CMV induces necrotic local lesions. The presence of CMV in the new symptomatic plants was corroborated through a reverse transcription polymerase chain reaction (RT-PCR) assay. Twelve days after sowing 117 plants had germinated (46%), of which 27 (23%) exhibited typical symptoms of viral infection that were observed on the first leaves. The reaction of cowpea plants to the inoculum from the plants that expressed viral symptoms was typical of the CMV. The presence of virus in these symptomatic plants was verified by RT-PCR amplification of viral DNA fragments of the expected size (500 bp). These tests demonstrated the transmission of the virus through the seeds of canna, which represents a source of primary inoculum. The seedborne characteristic increases the probability that the virus will survive in nature.
Revista De La Facultad De Agronomia De La Universidad Del Zulia, 2000
El virus del bandeado amarillo del sorgo (SYBV) es transmitido mecanicamente con dificultad (2-10... more El virus del bandeado amarillo del sorgo (SYBV) es transmitido mecanicamente con dificultad (2-10% de transmision) y los sintomas aparecen 15-25 dias despues de la inoculacion. Hasta el momento, no se le conocen vectores. Sin embargo, algunos resultados evidencian que un mecanismo a traves del suelo pudiera estar involucrado en la transmision del virus. En este estudio se evaluo la transmision del SYBV mediante tres tipos de inoculacion mecanica: inoculacion mecanica convencional, pistola a presion y puncion vascular de semillas de maiz. Durante la inoculacion mecanica convencional se utilizaron los siguientes tratamientos: dilucion de la savia infectiva, dos soluciones extractoras, diferentes buffers, variacion en el pH y molaridad de los buffers, adicion de sustancias reductoras, agentes quelantes y removedores de taninos. El SYBV fue transmitido eficientemente a traves de pistola a presion (65-80%) y mediante puncion vascular de semillas de maiz (60-85%); sin embargo, fue transmi...
ABSTRACT Recientemente fue detectado el JGMV infectando maíz (Zea mays) en Venezuela. Por esta ra... more ABSTRACT Recientemente fue detectado el JGMV infectando maíz (Zea mays) en Venezuela. Por esta razón, se consideró de interés realizar esta investigación con el objetivo de evaluar la reacción de 16 cultivares de maíz al JGMV. El experimento se realizó en la Facultad de Agronomía-UCV, en Maracay, bajo condiciones de invernadero (27 °C, 75% HR, 29000 lux). Los cultivares evaluados fueron: Platino 100, Sefloarca 108, Sefloarca 96, Sefloarca 91, Dorado 5, Sehiveca 01091, Sehiveca 01092, Sehiveca 01093, Sehiveca 01094, D2A-212, D2A-223, D2A-316, D2A-399, D 5008, Himeca 3002 y Tropical plus. Se utilizó un diseño completamente aleatorizado con 16 tratamientos (cultivares), 3 repeticiones por tratamiento y 6 plantas/repetición. Las plantas fueron inoculadas mecánicamente con el virus a los 8 y a los 16 días después de la siembra. El estadístico utilizado para la evaluación fue el índice de la enfermedad (IE), el cual se obtuvo a través de la ecuación siguiente: IE = 4W + 3X + 2Y + Z, donde W, X, Y y Z representan el porcentaje acumulado de plantas enfermas a los 6, 11, 16 y 28 d, respectivamente. Para el análisis de los resultados se aplicó la prueba de Kruskall-Wallis y la prueba no paramétrica para comparaciones múltiples entre tratamientos. El análisis de los resultados no generó grupos homogéneos; por lo tanto, no se puede afirmar estadísticamente que uno o más tratamientos son mejores que los otros, en términos del IE. Todos los cultivares fueron ubicados en un solo grupo que corresponde a la categoría de resistentes.
SUMMARY In banana and plantain (Musa spp.) production areas in Venezuela plants were observed wit... more SUMMARY In banana and plantain (Musa spp.) production areas in Venezuela plants were observed with foliar symptoms of a virus- like disease characterized by chlorotic streaks which often be- come progressively necrotic. In samples of the cultivars Pineo gigante (AAA) and Mysore (AAB), the banana streak virus (BSV) was detected by immunosorbent electron microscopy. Four virus isolates were identified by immunocapture followed by poly- merase chain reaction amplification (IC-PCR) using isolate-spe- cific oligonucleotide primers of two BSV strains. The results of IC-PCR indicated that the isolates occurring in the samples were BSV-OL. This strain is known to be integrated in the host genome (Musa) and there is evidence that BSV infection can arise from these integrated sequences. BSV was detected in the Venezuelan states of Aragua, Barinas, Carabobo, Delta Amacuro, Mérida, Miranda, Sucre, Yaracuy and Zulia.
Revista De La Facultad De Agronomia De La Universidad Del Zulia, 2016
La transmision de virus fitopatogenos por coleopteros fue considerada como un proceso mecanico en... more La transmision de virus fitopatogenos por coleopteros fue considerada como un proceso mecanico en el cual los virus que llevaban estos insectos en su aparato bucal o en los regurgitados los depositaban en las heridas ocasionadas al momento de la alimentacion. Trabajos recientes han demostrado que este proceso es muy especifico y biologicamente complejo, y no simplemente un problema de contaminacion de las partes bucales del vector. En este articulo se revisan los aspectos fundamentales del proceso de transmision de virus de plantas por coleopteros. Estos virus alcanzan una alta concentracion en los tejidos infectados, son relativamente estables, tienen particulas poliedricas de 25-30 nm de diametro, contienen ARN de cadena sencilla, son transmitidos facilmente por inoculacion mecanica y tienen una alta antigenicidad. Las especies de virus transmitidas por coleopteros pertenecen a los generos Bromovirus, Carmovirus, Comovirus, Machlomovirus, Sobemovirus y Tymovirus, mientras que las ...
El ají (Capsicum spp.) tiene amplio uso en el arte culinario por su fragancia y sabor típico, hac... more El ají (Capsicum spp.) tiene amplio uso en el arte culinario por su fragancia y sabor típico, haciéndolo en muchos casos más preferido que el pimentón. En Venezuela, su explotación se ha incrementado paulatinamente; sin embargo, es afectado por diversos patógenos, entre ellos los virus. El virus de la marchitez manchada del tomate (Tomato spotted wilt virus, TSWV; Tospovirus, Bunyaviridae) es considerado un virus muy peligroso, pudiendo causar pérdidas cuantiosas en solanáceas (25-100 %); infecta más de 1.000 especies de plantas y es cosmopolita. Recientemente, el TSWV fue detectado infectando gerbera (Gerbera jamesonii) en viveros en los Altos Mirandinos (Miranda), pudiendo estar diseminado en otros cultivos y malezas. Por esta razón, el objetivo de este trabajo fue determinar la respuesta de los cultivares de ají Llanerón y Chirel al TSWV. De cada cultivar se inocularon mecánicamente 25 plantas, en presencia de buffer fosfato 0,1 M, pH 8 + 1% de sulfito de sodio (relación 1:5, p/v...
ABSTRACT Yardlong bean [Vigna unguiculata subsp. sesquipedalis (L.) Verdc.] is a distinctive subs... more ABSTRACT Yardlong bean [Vigna unguiculata subsp. sesquipedalis (L.) Verdc.] is a distinctive subspecies of cowpea, with apparent origin in East Asia. Yardlong bean is characterized by extremely long and thin pods, and is considered one of the top ten Asian vegetables. It is now grown extensively in Asia, Europe, Oceania and Americas. In 2012, yardlong bean plants showing severe yellowing were found in an experimental plot at the Agronomy Faculty, UCV, in Aragua State, Venezuela. The observed incidence of foliar yellowing symptoms, resembling those associated with the infection of a bromovirus, was 30%. The field samples with virus-like symptoms of yellowing were collected for further studies. Previously, we reported the presence of Cowpea mild mottle virus (CPMMV), a carlavirus with filamentous particles, in yard long bean in the country (Brito et al., 2012), but electron microscope observations using the leaf-dip method excluded CPMMV, since symptomatic leaves contained icosahedral virus-like particles, ca. 26-28 nm in diameter. Leaf extracts from field samples were mechanically inoculated onto V. unguiculata cv. Tuy, Vigna. radiata, Phaseolus vulgaris L. cv. Tacarigua, Chenopodium quinoa Willd., C. amaranticolor Coste et A. Reyn, Gomphrena globosa L. and Glycine max (L.) Merr. All the seven mechanically inoculated plant species were found susceptible to the virus. Among these, C. amaranticolor, C. quinoa and G. globosa developed chlorotic local lesions 10-14 days post inoculation (dpi), while V. radiata developed local necrotic lesions on inoculated leaves. Seedlings of V. unguiculata and G. max were found systemically infected and showed mottle and mosaic symptoms on upper non-inoculated leaves at 7 dpi. Extensive severe systemic chlorosis was developed in cowpea after 15 dpi. A virus isolate was propagated in V. unguiculata cv. Tuy, grown under greenhouse conditions, purified (de Carvalho et al., 2013), and tested by Western blot using polyclonal antisera specific to Cowpea mosaic virus (CPMV), Southern bean mosaic virus (SBMV), Broad bean mottle virus (BBMV), Cucumber mosaic virus (CMV) and Cowpea chlorotic mottle virus (CCMV). A conspicuous immunoreactive band with an approximate size of 19 kDa was obtained in purified virus sample against BBMV and CCMV antisera. Total RNA was extracted from 20 symptomatic plants and from purified virions, and tested by RT-PCR using degenerate primers Ilar1F5 (GCNGGWTGYGGDAARWCNAC) and Ilar1R7 (AMDGGWAYYTGYTNYGTRTCACC), specific to the detection of members of the genus Ilarvirus and family Bromoviridae (Untiveros et al., 2010). A PCR fragment of the expected size (ca. 300 bp) was amplified for all samples. Two amplicons were sequenced and the identical (100%) consensus sequences submitted to the GenBank database (NCBI, USA), with the accession numbers KJ810515 (from field yardlong bean) and KJ810516 (from purified virions). The deduced amino acid sequence contained 97 residues encoding part of the viral methyltransferase which was 93% identical to that of a CCMV methyltransferase (AAN37635.1). A nucleotide BLAST analysis of the sequence revealed 85% identity with CCMV strain T (AF325739). The level of sequence similarity with CCMV suggested that the virus from yardlong bean may be a distinct strain of this species. Phylogenetic analysis of the putative methyltransferase gene demonstrated that CCMV yardlong bean clustered separately form the known strains of CCMV. Because chrysomelids are known vectors of bromoviruses, virus-free Andrector ruficornis Olivier, A. arcuatus Olivier and Ledesmodina auricollis Lèfevre adults were exposed to symptomatic cowpea leaves for a 48-hour acquisition access period and then cage-confined with 10 healthy V. unguiculata cv. Tuy and P.vulgaris cv. Tacarigua each for a 48-hour inoculation access period. Symptoms were reproduced in all tested plants after 21-day period and CCMV infection was confirmed by RT-PCR assay. To our knowledge, this is the first evidence of the presence of CCMV in yardlong bean, and the first report of CCMV transmission by chrysomelid beetle L. auricollis. This is an important information for the Venezuelan cowpea’s market as CCMV-infected yardlong bean plants could act as virus source for secondary spread by beetle vectors. References: de Carvalho et al. Tropical Plant Pathology 38(1): 49-54, 2013., Untiveros et al., J. Virol. Methods 165: 97-104, 2010., Brito et al., Viruses 4: 3804-3811, 2012.
ABSTRACT Seeds as a source of Cucumber mosaic virus (CMV) have been reported in several species o... more ABSTRACT Seeds as a source of Cucumber mosaic virus (CMV) have been reported in several species of plants, but in the literature no results of this type of transmission were found in canna. For this reason, it was considered of interest this research in order to determine if CMV is transmitted directly through the seed of canna (Canna indica). To do this, were collected 254 seeds from infected plants and sown individually in plastic containers containing sterile substrate. Evaluations were performed for a month under greenhouse conditions. Sap from new plants showing viral symptoms was extracted and used to mechanically inoculate cotyledonary leaves of healthy cowpea (Vigna unguiculata) cv Tuy plants in which CMV induces necrotic local lesions. The presence of CMV in the new symptomatic plants was corroborated through a reverse transcription polymerase chain reaction (RT-PCR) assay. Twelve days after sowing 117 plants had germinated (46%), of which 27 (23%) exhibited typical symptoms of viral infection that were observed on the first leaves. The reaction of cowpea plants to the inoculum from the plants that expressed viral symptoms was typical of the CMV. The presence of virus in these symptomatic plants was verified by RT-PCR amplification of viral DNA fragments of the expected size (500 bp). These tests demonstrated the transmission of the virus through the seeds of canna, which represents a source of primary inoculum. The seedborne characteristic increases the probability that the virus will survive in nature.
Revista De La Facultad De Agronomia De La Universidad Del Zulia, 2000
El virus del bandeado amarillo del sorgo (SYBV) es transmitido mecanicamente con dificultad (2-10... more El virus del bandeado amarillo del sorgo (SYBV) es transmitido mecanicamente con dificultad (2-10% de transmision) y los sintomas aparecen 15-25 dias despues de la inoculacion. Hasta el momento, no se le conocen vectores. Sin embargo, algunos resultados evidencian que un mecanismo a traves del suelo pudiera estar involucrado en la transmision del virus. En este estudio se evaluo la transmision del SYBV mediante tres tipos de inoculacion mecanica: inoculacion mecanica convencional, pistola a presion y puncion vascular de semillas de maiz. Durante la inoculacion mecanica convencional se utilizaron los siguientes tratamientos: dilucion de la savia infectiva, dos soluciones extractoras, diferentes buffers, variacion en el pH y molaridad de los buffers, adicion de sustancias reductoras, agentes quelantes y removedores de taninos. El SYBV fue transmitido eficientemente a traves de pistola a presion (65-80%) y mediante puncion vascular de semillas de maiz (60-85%); sin embargo, fue transmi...
ABSTRACT Recientemente fue detectado el JGMV infectando maíz (Zea mays) en Venezuela. Por esta ra... more ABSTRACT Recientemente fue detectado el JGMV infectando maíz (Zea mays) en Venezuela. Por esta razón, se consideró de interés realizar esta investigación con el objetivo de evaluar la reacción de 16 cultivares de maíz al JGMV. El experimento se realizó en la Facultad de Agronomía-UCV, en Maracay, bajo condiciones de invernadero (27 °C, 75% HR, 29000 lux). Los cultivares evaluados fueron: Platino 100, Sefloarca 108, Sefloarca 96, Sefloarca 91, Dorado 5, Sehiveca 01091, Sehiveca 01092, Sehiveca 01093, Sehiveca 01094, D2A-212, D2A-223, D2A-316, D2A-399, D 5008, Himeca 3002 y Tropical plus. Se utilizó un diseño completamente aleatorizado con 16 tratamientos (cultivares), 3 repeticiones por tratamiento y 6 plantas/repetición. Las plantas fueron inoculadas mecánicamente con el virus a los 8 y a los 16 días después de la siembra. El estadístico utilizado para la evaluación fue el índice de la enfermedad (IE), el cual se obtuvo a través de la ecuación siguiente: IE = 4W + 3X + 2Y + Z, donde W, X, Y y Z representan el porcentaje acumulado de plantas enfermas a los 6, 11, 16 y 28 d, respectivamente. Para el análisis de los resultados se aplicó la prueba de Kruskall-Wallis y la prueba no paramétrica para comparaciones múltiples entre tratamientos. El análisis de los resultados no generó grupos homogéneos; por lo tanto, no se puede afirmar estadísticamente que uno o más tratamientos son mejores que los otros, en términos del IE. Todos los cultivares fueron ubicados en un solo grupo que corresponde a la categoría de resistentes.
SUMMARY In banana and plantain (Musa spp.) production areas in Venezuela plants were observed wit... more SUMMARY In banana and plantain (Musa spp.) production areas in Venezuela plants were observed with foliar symptoms of a virus- like disease characterized by chlorotic streaks which often be- come progressively necrotic. In samples of the cultivars Pineo gigante (AAA) and Mysore (AAB), the banana streak virus (BSV) was detected by immunosorbent electron microscopy. Four virus isolates were identified by immunocapture followed by poly- merase chain reaction amplification (IC-PCR) using isolate-spe- cific oligonucleotide primers of two BSV strains. The results of IC-PCR indicated that the isolates occurring in the samples were BSV-OL. This strain is known to be integrated in the host genome (Musa) and there is evidence that BSV infection can arise from these integrated sequences. BSV was detected in the Venezuelan states of Aragua, Barinas, Carabobo, Delta Amacuro, Mérida, Miranda, Sucre, Yaracuy and Zulia.
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