Characterization of Cowpea aphid-borne mosaic virus in Passiflora edulis 'Catarina' in the southern coast of Santa Catarina State, Brazil / Caracterização do Cowpea aphid-borne mosaic virus em Passiflora edulis cv. Catarina no litoral sul de Santa Catarina, Brasil

CABMV is a limiting virus for passion fruit crop in Brazil, its main producing country. This virus has been reported in all producing states of the country, with the state of Santa Catarina (SC) in 2017 standing as the third largest passion fruit producer. In 2017, it reached 8.4% of the national production. The southern coast is the main responsible for the increase in production, which has been supplying the domestic market. However, in that same year, this region recorded the first symptom expressions in plants and fruits. The evaluation of the samples collected in the municipalities of Sombrio, Praia Grande and São João do Sul, southern coast of SC, was performed by using a mechanical transmission to indicator plants, PTA-ELISA and RT-PCR, and by sequencing. The evaluation results were positive for CABMV and negative for CMV in PTA-ELISA. In RT-PCR, there was the formation of a 700bp ca band, expected size for Potyvirus, whose sequence comparison with those deposited in GenBank reveled 98% identity with the isolates from São Paulo State. The occurrence of the virus in the southern coast of SC did not reach a serious decrease in passion fruit production due to the union of producers, who adopted preventive management measures to control the virus, whose effect led to a consolidation of the passion fruit production chain in the region.(AU)

O CABMV é um vírus limitante para a cultura do maracujá no Brasil, principal país produtor mundial, cuja ocorrência já foi relatada em todos os estados produtores. Em 2017, o estado de Santa Catarina (SC) foi o terceiro maior produtor de maracujá no Brasil, responsável por 8,4% da produção nacional, sendo o litoral sul o principal responsável pelo aumento da produção, garantindo o abastecimento do mercado interno. Entretanto, nesse mesmo ano, essa região registrou as primeiras expressões de sintomas em plantas e frutos. Uma avaliação das amostras coletadas nos municípios de Sombrio, Praia Grande e São João do Sul, litoral sul de Santa Catarina, foi realizada por transmissão mecânica para plantas indicadoras, PTA-ELISA, RT-PCR e sequenciamento. Os resultados foram positivos para o CABMV e negativos para o CMV, tanto em PTA-ELISA quanto RT-PCR. Na RT-PCR, houve a amplificação de bandas com ca de 700pb, tamanho esperado para o Potyvirus cuja comparação de sequências com as depositadas no GenBank revelaram 98% de similaridade com os isolados do estado de São Paulo. A ocorrência do vírus na região do litoral sul de Santa Catarina não causou quebra na produção de maracujá devido à adoção conjunta de medidas preventivas de manejo pelos produtores, fato que consolidou a cadeia produtiva do maracujá na região.(AU)

Incidencia de potyvirus y caracterización molecular de PVY en regiones productoras de papa (Solanum tuberosum L) de Colombia / Incidence of potyvirus and molecular characterization of PVY in potato (Solanum tuberosum L) growing regions of Colombia

Los problemas virales reducen los rendimientos y la calidad del tubérculo semilla en cultivos de papa de todo el mundo. Esta investigación se planteó con el fin de evaluar los niveles de incidencia de potyvirus en diez de las principales regiones cultivadoras de papa de los departamentos de Antioquia, Boyacá, Cundinamarca y Nariño (Colombia), y las características genotípicas del virus Y de la papa (Potato virus Y, PVY), seleccionado por ser el potyvirus más limitante de este cultivo. Para la evaluación de la incidencia se utilizaron pruebas de Elisa con anticuerpos que reconocen epítopes comunes a los potyvirus, mientras que las pruebas moleculares incluyeron el análisis filogenético de secuencias parciales del gen de la cápside viral de 33 aislamientos, así como la secuenciación de una porción de los extremos 5´ y 3´del genoma de dos cepas colombianas de este virus. Los resultados confirmaron la presencia de potyvirus en los cultivos de los cuatro departamentos evaluados, con una incidencia promedio del 72%, siendo este nivel superior al 56% en todas las zonas evaluadas. Los análisis moleculares del PVY, permitieron asociar las cepas colombianas estudiadas con las razas PVYN y la variante PVYNTN, esta última responsable de la enfermedad conocida en el mundo como PTNRD (Potato tuber necrotic ringspot disease).

Potato viruses are responsible for significant reductions in seed quality and crop yields around the world. In this study, we evaluate the levels of incidence of potyvirus in ten potato growing regions of Colombia from the provinces of Antioquia, Boyacá, Cundinamarca and Nariño. As PVY is the most limiting potyvirus in potato farming, a molecular characterization of Colombian PVY strains was also performed. Incidence was evaluated by ELISA using general potyvirus antibodies. Phylogenetic analysis were made on the partial sequence of the capsid gene from 33 isolates. A portion of the 5´ and 3' genome ends was obtained from two Colombian strains. Results confirmed the presence of potyvirus in the four provinces with an average incidence of 72%. The lowest incidence value was 56%. Molecular analysis clustered all Colombian isolates with strains PVYN and PVYNTN, the latter responsible for the disease known as PTNRD (Potato tuber necrotic ringspot disease).

Localization of sweet potato chlorotic stunt virus (SPCSV) in synergic infection with potyviruses in sweet potato

Among diseases reported worldwidely for sweet potato (Ipomoea batatas (L) Lam) crop, one of the most frequent is the Sweet potato virus disease (SPVD), caused by sweet potato chlorotic stunt virus (SPCSV) and sweet potato feathery mottle virus (SPFMV) co-infection. In Argentina, there exists the sweet potato chlorotic dwarf (SPCD), a sweet potato disease caused by triple co-infection with SPCSV, SPFMV and sweet potato mild speckling virus (SPMSV). Both diseases cause a synergism between the potyviruses (SPFMV and SPMSV) and the crinivirus (SPCSV). Up to date, studies carried out on the interaction among these three viruses have not described their localization in the infected tissues. In single infections, virions of the crinivirus genus are limited to the phloem while potyviral virions are found in most tissues of the infected plant. The purpose of this work was to localize the heat shock protein 70 homolog (HSP70h), a movement protein for genus crinivirus, of an Argentinean SPCSV isolate in its single infection and in its double and triple co-infection with SPFMV and SPMSV. The localization was made by in situ hybridization (ISH) for electron microscopy (EM) on ultrathin sections of sweet potato cv. Morada INTA infected tissues. The results demonstrated that viral RNA coding HSP70h is restricted to phloem cells during crinivirus single infection, while it was detected outside the phloem in infections combined with the potyviruses involved in chlorotic dwarf disease.