Crotalaria paulinea, novo hospedeiro natural do vírus do mosaico severo do caupi

Abstract

Amostras foliares de Crotalaria paulinea apresentando mosaico foram coletadas em São Luiz, MA, e enviadas ao Laboratório de Virologia Vegetal da UFC. As amostras foram testadas por Elisa indireto, contra anti-soros para Cowpea aphid-borne mosaic virus (CABMV) e Cucumber mosaic virus (CMV) e por dupla difusão em àgar contra anti-soro para Cowpea severe mosaic virus (CPSMV). As amostras reagiram somente com o anti-soro para CPSMV, indicando ser C. paulinea mais um hospedeiro natural do vírus. Extratos das folhas de C. paulinea foram inoculados em plantas de caupi (Vigna unguiculata subsp. unguiculata) mantidas em casa de vegetação. Dez dias após a inoculação, as plantas passaram a exibir sintomas de mosaico e a presença do CPSMV foi confirmada por sorologia. Nos estudos de gama de hospedeiros, envolvendo oito espécies botânicas, o isolado de CPSMV obtido de C. paulinea (CPSMV-Cp) infetou sistemicamente somente cultivares de caupi. Estudos de reações de RT-PCR revelaram a presença de uma banda no gel de agarose de 594 pb para o CPSNV-Cp semelhante às de outros isolados de CPSMV. O CPSMV-Cp foi multiplicado em caupi cv. Pitiúba e purificado por clarificação com n-butanol, precipitação viral com PEG e ultracentrifugação. A preparação purificada apresentou um espectro de absorção ultravioleta típico de núcleoproteína com uma razão A260/A280 de 1,7. Coelho da raça Nova Zelândia Branca imunizado com a preparação viral purificada, produziu anti-soro policlonal reativo com CPSMV em dupla difusão em àgar. Este é o primeiro relato sobre a infecção natural de CPSMV em C. paulinea.

Biological stability of a strain of Cowpea severe mosaic virus over 20 years

“…The genetic variability presented by plant viruses, mailing and most commonly by those with divided genome such as the case of CPSMV is evidenced by the great number of isolates biologically and genetically different from the wild type of the virus (DE JAGER, 1979;FAUQUET et al, 2005). The great range of CPSMV isolates obtained and characterized in the Plant Virus Laboratory at the Federal University of Ceará is a great evidence of that (LIMA; NELSON, 1974;LIMA et al, 2005;SITTOLIN;LIMA, 2005).…”

Biological, serological and molecular comparison between isolates of Cowpea severe mosaic virus

“…These results represent the first biological criteria for differentiation of CPSMV isolates. The purified preparations of CPSMV-AL, CPSMV-CROT and CPSMV-PE showed ultra violet spectra typical of polyhedral virus particles and the final virus concentrations (33 mg of virus/Kg of infected tissue) were compatible for CPSMV (Lima & Nelson, 1974;Lima et al, 1998;Lima et al, 2005a). The absence of spur formation between the different virus isolates in double immune diffusion is an indication of their serological identity.…”

“…The molecular comparison between CPSMV-PE and Cowpea mosaic virus (CPMV), a different but related virus species from the genus Comovirus (Swaans & Kammen, 1973), showed a close relationship between them (Figure 2). The occurrence of CPMV has not yet been reported in Brazil (Lima & Nelson, 1974, 1977Lin et 1981; Lima et al, 2005aLima et al, , 2005b. A low sequence similarity (74%) was observed between CPSMV-PE and an isolate of CPSMV obtained in Central America designated CPSMV-VU (Kammen & Jager, 1978;Jager, 1979), revealing a significant genetic difference that could be attributed to geographic localization.…”

“…Although CPSMV presents a large biological variability with a wide host range in the leguminous family (Lima et al, 2005a), neither isolate studied infected C. occidentalis, C. ternatea, Leucaena sp. and P. vulgaris.…”

“…unguiculata is an important legume crop, with great capacity to supply the population with protein and carbohydrates in the Northeast of Brazil. The most important viruses that infect cowpea in Brazil belong to the following families and genera: family Comoviridae, genus Comovirus; family Potyviridae, genus Potyvirus; family Bromoviridae, genus Cucumovirus, and family Geminiviridade, genus Begomovirus (Lima et al, 2005a). Cowpea severe mosaic virus (CPSMV), which belongs to the family Comoviridae and genus Comovirus, has stood out for its severity and degree of incidence.…”