Levantamento revela a predominância do Lettuce mottle virus em três regiões produtoras de alface no Estado de São Paulo

Abstract

Among the phytosanitary problems affecting lettuce culture are the diseases caused by viruses. Three viruses cause almost indistinguishable mosaic symptoms: Lettuce mosaic virus (LMV, Potyvirus), Lettuce mottle virus (LeMoV, Sequivirus) and Bidens mosaic virus (BiMV, Potyvirus). By RT-PCR using specific primers for each virus, lettuce and weed samples, preferably with mosaic symptoms, and collected from lettuce fields in the regions of Mogi v.38, n.3, p.245-247, 2012. das Cruzes, Campinas and Bauru, São Paulo State, Brazil, were analyzed for the presence of these viruses. LeMoV was the most frequently found virus, followed by LMV. The occurrence of BiMV in lettuce was extremely low and restricted to the regions of Campinas and Bauru, where it was also found in weeds such as Bidens pilosa and Galinsoga parviflora. The latter plant is the host of these three viruses.Additional keywords: LMV, LeMoV, BiMV. ABSTRACTA alface é infectada por diversos vírus que causam sintomas de mosaico, distorção foliar e necrose resultando em perda na qualidade do produto. Dentre esses vírus destacam-se o Lettuce mosaic virus, LMV pertencente ao gênero Potyvirus, considerado o mais importante na cultura (4), o Lettuce mottle virus, LeMoV possível membro do gênero Sequivirus e os vírus do gênero Tospovirus, causadores da doença conhecida como vira-cabeça. Além destes, o Bidens mosaic virus (BiMV), espécie tentativa no gênero Potyvirus, e o Cucumber mosaic virus (CMV, Cucumovirus) também infectam a alface (6).Dispondo de oligonucleotídeos sensíveis e específicos para o LMV, LeMoV e BiMV, todos causadores de sintomas de mosaico muito similares, o objetivo deste trabalho foi de avaliar a ocorrência do LMV, LeMoV e do BiMV, nos campos de produção de alface de três regiões do estado de São Paulo. v.38, n.3, p.245-247, 2012. coletadas em campos de produção de alface das regiões de Mogi das Cruzes, Campinas e Bauru no Estado de São Paulo e analisadas para a presença dos vírus. Verificou-se que o LeMoV foi o vírus encontrado com maior freqüência, seguido do LMV. A ocorrência de BiMV em alface foi extremamente baixa e restrita às regiões de Campinas e Bauru, onde também foi verificado em plantas invasoras como Bidens pilosa e Galinsoga parviflora. Esta ultima é hospedeira dos três vírus.

Molecular and Biological Characterization of Novel and Known Family Secoviridae Members Infecting Lettuce

“…It should be noted that in the absence of fully conclusive diagnostics at the time, older reports of the presence of DaYMV in French lettuce crops(Blancard et al 2003) might, in fact, have been related to LeMoV or LSMV.Previous surveys of lettuce crops in France suggest that LSMV or LeMoV are rare, even though wild lettuce may possibly act as a reservoir in the absence of lettuce crops (hence the HTS analysis of the JG1 and JG2 plants following the observation of unusual symptoms). This situation is, at least for LeMoV, in contrast to that reported in the early 2000s in Brazil where LeMoV was considered the first or second most important lettuce virus, with a reported prevalence of 10.1%-26.1% under open field conditions in Sao Paulo stateDe Marchi et al 2012). However, this situation changed during the last years, with…”

“…LeMoV, differing from DaYMV in host range, is a distinct sequivirus infecting lettuce in Brazil and in Chile (Krause-Sakate et al 2005;Jadao et al 2007). In Brazil, and in particular in Sao Paulo State, LeMoV was in the early 2000s the most frequent virus in lettuce crops (De Marchi et al 2012, Krause-Sakate et al 2007 but it has so far never been reported outside of South America. For both DaYMV and LeMoV, only very short, partial genome sequences are available (Jadao et al 2007) and there is very little information available on their genetic variability.…”