Detecção e análise da variabilidade de seqüências do Banana streak virus (BSV) em bananeiras no Brasil Detection and analysis of Banana streak virus (BSV) sequences variability of banana from Brazil

A técnica de PCR utilizando-se "primers" degenerados para o gênero Badnavirus foi utilizada para a detecção e análise da variabilidade de seqüências do Banana streak virus (BSV) provenientes de bananeiras. A partir desta metodologia seqüências do vírus puderam ser detectadas em cultivares diplóides (AA), triplóides (AAA; AAB) e tetraplóides (AAAB). Foram encontrados quatro padrões de seqüência do BSV (estirpes BSVBR-1, BSVBR-2, BSVBR-3 e BSVBR-4), diferenciadas através da análise do perfil eletroforético das amostras amplificadas. A estirpe BSVBR-1 prevalece nos estados do Acre, Amazonas, Bahia, Ceará, Goiás, Minas Gerais, Piauí, Rio de Janeiro, Rondônia, Santa Catarina, e São Paulo, enquanto que, a estirpe BSVBR-2 foi encontrada em amostras oriundas do Amazonas e do Ceará. As estirpes BSVBR-3 e BSVBR-4 foram encontradas apenas no Ceará. Este trabalho revela a presença de diferentes estirpes do BSV no Brasil, bem como a existência de cultivares de bananeiras sadias e livres de seqüências virais do BSV integradas ao seu genoma.<br>PCR assay using degenerate primers, designed to Badnavirus genus, was used to detect and analyse the variability of BSV strains sequences from banana. The virus was detected in diploid (AA), triploids (AAA; AAB) and tetraploids (AAAB) banana cultivars. Four BSV sequences patterns (BSVBR-1, BSVBR-2, BSVBR-3 and BSVBR-4 strains) were found, and distinguished by eletrophoresis. The strain BSVBR-1 was found in the states of Acre, Amazonas, Bahia, Ceará, Goiás, Minas Gerais, Piauí, Rio de Janeiro, Rondônia, Santa Catarina and São Paulo, while BSVBR-2 strain was detected in the states of Amazonas and Ceará. BSVBR-3 and BSVBR-4 strains were found only in the state of Ceará. This work demonstrated the presence of different BSV strains in Brazil and the existence of health banana cultivars as well as cultivars free of BSV integrated sequences

Biological and physicochemical properties of cowpea severe mosaic comovirus isolated from soybean in the State of Paraná

Soybean plants with symptoms of bud blight were growing close to cowpea with severe symptoms of mosaic associated with blisters in the leaves. A group of plants of both species were collected and used for etiological studies. This kind of symptom in soybeans was common in certain areas of the State of Paraná, induced by tobacco streak ilarvirus. Host range, serological reaction, particle morphology and size, protein and nucleic acid analysis, and transmission by beetles from species Cerotoma arcuata Oliv. showed that the virus involved was cowpea severe mosaic comovirus. This is the first report on the occurrence of this virus in soybean plants in the State of Paraná. Results using indirect ELISA showed that in cowpea the relative virus concentration was higher in green leaf areas than in chlorotic ones. Also, virus concentration, determined through indirect ELISA was much higher in plants kept at diurnal regime of 25º C x 23º C (12 x 12 h) than at 30º C x 28º C

The citrus leprosis pathosystem O patossistema leprose dos citros

Citrus leprosis is considered the main viral disease for the Brazilian citrus production, particularly for the State of São Paulo, due to the high costs spent for the chemical control of its vector, the tenuipalpid mite Brevipalpus phoenicis. In addition, its global importance has significantly increased in the last years, with the dissemination of the virus to new countries in South and Central America. In Brazil, despite its economical importance and occurrence for more than seven decades, the most significant advances towards understanding the pathosystem interactions have been obtained only in the last ten years. This review focuses on various aspects of the disease, beginning with a historical view, its main characteristics, alternatives for its control, its increasing economical importance in Brazil and abroad, and the new data on the search for understanding the interactions amongst the mite vector, the virus, and the plant host.<br>A leprose dos citros é considerada a principal virose na citricultura brasileira, com maior destaque no Estado de São Paulo, principalmente pelos altos custos demandados para o controle químico do vetor, o ácaro Brevipalpus phoenicis. Além da relevância dessa virose para a citricultura local, sua importância mundial vem sendo ampliada consideravelmente nos últimos anos, principalmente com a disseminação do vírus em novos países da América do Sul e Central. No Brasil, apesar da sua importância econômica e ocorrência por mais de sete décadas, os mais importantes avanços no entendimento das interações do patossistema leprose têm sido obtidos apenas nos últimos dez anos. Essa revisão aborda os diferentes aspectos dessa doença, trazendo um breve histórico da doença, principais características da leprose, alternativas de controle, sua crescente importância econômica na cadeia citrícola nacional, os mais recentes relatos de sua ocorrência em outros países e os novos resultados obtidos pela pesquisa buscando um melhor entendimento das interações entre ácaro, vírus e hospedeiro vegetal