Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Molecular characterization of two brazilian isolates of Lettuce mosaic virus with distinct biological properties(Fitopatologia Brasileira, 2001-06) Krause- Sakate, Renate; Mello, Raquel N.; Pavan, Marcelo A.; Zambolim, Eunize M.; Carvalho, Murilo G.; Gall, Olivier Le; Zerbini, F. Murilo; Krause-Sakate, RenateThe coat protein genes of two field isolates of Lettuce mosaic virus (LMV) from São Paulo State, previously characterized based on their virulence on lettuce (Lactuca sativa) differential cultivars as belonging to pathotypes II (isolate AF198, unable to infect cultivars possessing the genes mo11 or mo12) and IV (isolate AF199, which breaks the resistance conferred by mo11 or mo12), were cloned and sequenced. Comparisons of the nucleotide sequences from European, Middle-Eastern, North American, and the two Brazilian isolates did not distinguish strains, because homologies were always greater than 95%. However, phylogenetic analysis indicated that the Brazilian isolate AF198 clusters with isolates LMV-R and LMV-0 (pathotype II, from the United States and France, respectively). Isolate AF199 clustered with two isolates (LMV-Aud and LMV-13) from France. These isolates are also closely related to isolates from Chile, although a common origin is not proposed. Independent mutation events may be occurring in different parts of the world, leading to the emergence of distinct LMV strains capable of overcoming the resistance genes mo11 or mo12.Item Caracterização de um isolado do Bean rugose mosaic virus (BRMV) de Minas Gerais e estimativa de perdas em feijoeiro em infecção simples ou em conjunto com o BCMV(Fitopatologia Brasileira, 2006-09) Maia, Felipe G. M.; Carvalho, Murilo G.; Pinto, Cleide M. F.; Zerbini, F. Murilo; Castillo-Urquiza, Gloria P.Plantas de feijão-vagem do cultivar Novirex apresentando mosaico e enrolamento de vagens, sem deformação foliar evidente, foram coletadas em 2002 em Cordisburgo, MG. Estudos preliminares identificaram o vírus como um isolado do Bean rugose mosaic virus (BRMV). Este trabalho relata a caracterização do isolado, por meio de produção e avaliação de anti-soro, determinação da gama de hospedeiros, estudo da transmissão do vírus por besouros crisomelídeos e estimativa de perdas em feijoeiro como resultado de infecção isolada ou em conjunto com o Bean common mosaic virus (BCMV). O roteiro adotado para purificação possibilitou a obtenção de vírus purificado em rendimento satisfatório para a produção de anti-soro. A titulação dos anti-soros foi realizada por ELISA indireto, obtendo-se reações positivas com a diluição máxima testada (1:70.000). Das 22 espécies vegetais utilizadas na gama de hospedeiros, foram infectadas plantas de Chenopodium quinoa e alguns cultivares de feijão e soja, conforme esperado para o BRMV. O isolado de BRMV foi transmitido pelo besouro crisomelídeo Cerotoma arcuata a uma taxa de 33,3%. A infecção simples de feijão 'Ouro Negro' e de feijão-vagem 'Novirex' levou a uma redução do peso das vagens por planta de 3,4% e 84,9%, respectivamente. Infecção mista do BRMV com o BCMV levou a uma redução do peso de vagens por planta de até 70,1% para 'Novirex' e de até 90,8% para 'Ouro Negro'.Item Efeitos na fotossíntese e área foliar de cultivares de alface inoculadas mecanicamente com patótipos do Lettuce mosaic virus e Lettuce mottle virus(Fitopatologia Brasileira, 2004-01) Jadão, Adriana S.; Pavan, Marcelo A.; Krause-Sakate, Renate; Zerbini, F. MuriloLevantamentos realizados no estado de São Paulo indicaram a ocorrência isolada e em infecções mistas do Lettuce mosaic virus (LMV) e do Lettuce mottle virus (LeMoV) em plantas de alface (Lactuca sativa). O presente trabalho teve como objetivo estudar os efeitos da infecção isolada e mista entre o LMV (patótipos II e IV) e o LeMoV, em cultivares de alface suscetível (White Boston) e tolerante (Elisa - gene mol1) ao LMV patótipo II. As plantas foram inoculadas via extrato vegetal tamponado com isolados de LMV-II, LMV-IV e LeMoV separadamente e em diferentes combinações, com intervalo de 24 h ou simultaneamente com os dois vírus. As plantas infetadas foram analisadas utilizando-se hospedeiras diferenciais para o LMV e o LeMoV, e no caso do LMV pelo teste sorológico de PTA-ELISA. Nas avaliações de peso fresco e seco, área foliar e teor de clorofila, observou-se que a cultivar White Boston foi a mais afetada por ambos os vírus. As infecções mistas e isoladas na cultivar Elisa causaram efeitos semelhantes, provavelmente devido a presença do gene mo11 de tolerância ao LMV-II. O isolado LMV-IV foi considerado o mais agressivo nestas cultivares quando comparado ao LMV-II e o LeMoV.Item Genetic diversity of begomoviruses infecting soybean, bean and associated weeds in Northwestern Argentina(Fitopatologia Brasileira, 2006-07) Rodríguez-Pardina, Patricia E.; Zerbini, F. Murilo; Ducasse, Daniel A.The subtropical Northwestern region of Argentina (provinces of Tucumán, Salta, Jujuy, Santiago del Estero and Catamarca) suffers from a high incidence of the whitefly Bemisia tabaci, and the detection of begomoviruses is also common. The Northwest is the main bean-growing region of the country, and approximately 10% of Argentina's soybean crop is grown in this area. We have used a PCR-based assay to establish the identity and genetic diversity of begomoviruses associated with bean and soybean crops in Northwestern Argentina. Universal begomovirus primers were used to direct the amplification of a fragment encompassing the 5' portion of the capsid protein gene. Amplified fragments were cloned, sequenced and subjected to phylogenetic analysis to determine the sequence identity to known begomoviruses. The data indicated the presence of four distinct begomoviruses, all related to other New World begomoviruses. The prevalent virus, which was present in 94% of bean and soybean samples and also in two weed species, is closely related to Sida mottle virus (SiMoV). A virus with high sequence identity with Bean golden mosaic virus (BGMV) was found in beans. The two remaining viruses displayed less than 89% identity with other known begomoviruses, indicating that they may constitute novel species. One of these putative novel viruses was detected in bean, soybean and tomato samples.Item Molecular mapping of the viral determinants of systemic wilting induced by a Lettuce mosaic virus (LMV) isolate in some lettuce cultivars(Virus Research, 2005-05) Zerbini, F. Murilo; Krause-Sakate, Renate; Redondo, Elise; Richard-Forget, Florence; Jadão, Adriana Salomão; German-Retana, Sylvie; Pavan, Marcelo Agenor; Candresse, Thierry; Gall, Olivier Le; Houvenaghel, Marie ChristineThe isolate AF199 of Lettuce mosaic virus (LMV, genus Potyvirus) causes local lesions followed by systemic wilting and plant death in the lettuce cultivars Ithaca and Vanguard 75. Analysis of the phenotype of virus chimeras revealed that a region within the P1 protein coding region (nucleotides 112–386 in the viral genome) and/or another one within the CI protein coding region (nucleotides 5496–5855) are sufficient together to cause the lethal wilting in Ithaca, but not in Vanguard 75. This indicates that the determinants of this particular symptom are different in these two lettuce cultivars. The wilting phenotype was not directly correlated with differences in the deduced amino acid sequence of these two regions. Furthermore, transient expression of the LMV-AF199 proteins, separately or in combination, did not induce local necrosis or any other visible reaction in the plants. Together, these results suggest that the systemic wilting reaction might be due to RNA rather than protein sequences.Item Cowpea aphid-borne mosaic virus (CABMV) is widespread in passionfruit in Brazil and causes passionfruit woodiness disease(Archives of Virology, 2006-04-07) Nascimento, A. V. S.; Santana, E. N.; Braz, A. S. K.; Alfenas, P. F.; Pio-Ribeiro, G.; Andrade, G. P.; Carvalho, M. G. de; Zerbini, F. MuriloLeaf samples of yellow passionfruit (Passiflora edulis f. flavicarpa) displaying fruit woodiness symptoms were collected in seven Brazilian states and the Federal District. Viral infection was confirmed by host range and ELISA, and fourteen viral isolates were obtained. All isolates were capable of infecting several leguminous host species, although differences in symptom severity were noticeable. Woodiness symptoms were reproduced in yellow passionfruit, and mosaic symptoms were induced in common bean. All isolates infected cowpea, reported as a non-host of passion fruit woodiness virus (PWV). Indirect ELISA demonstrated that all isolates were serologically related to each other and also to cowpea aphid-borne mosaic virus (CABMV). The complete sequence of the capsid protein was determined for all isolates. Comparison of these sequences with those of other potyviruses indicated the highest identity with CABMV isolates (85 to 94%). Identity with PWV isolates ranged from 54 to 70%. Phylogenetic analysis grouped all of the Brazilian isolates in a monophyletic cluster with the CABMV isolates, clearly distinct from the PWV isolates. Furthermore, this analysis demonstrated that a group of previously characterized isolates from Brazil that had been designated as PWV should be reclassified as CABMV. Together, these results provide unequivocal evidence that, in Brazil, passionfruit woodiness disease is primarily caused by CABMV. The presence of PWV in Brazil has yet to be confirmed.Item Six novel begomoviruses infecting tomato and associated weeds in Southeastern Brazil(Archives of Virology, 2008-08-24) Castillo-Urquiza, Gloria P.; Beserra Jr., José Evando A.; Bruckner, Fernanda P.; Lima, Alison T. M.; Varsani, Arvind; Alfenas-Zerbini, Poliane; Zerbini, F. MuriloThe incidence of tomato-infecting begomoviruses has sharply increased in Brazil following the introduction of the B biotype of the whitefly vector in the early 1990s. Five definitive species and six tentative species have been described since then. Here, we report the detection of members of an additional six novel species, three in tomato and three infecting weeds that are commonly associated with tomato fields: Blainvillea rhomboidea, Sida rhombifolia and Sida micrantha. Tomato and weed samples were collected in two major tomato-growing regions of southeastern Brazil in 2005 and 2007. Two of the novel viruses were present in tomato plants collected in Paty do Alferes, Rio de Janeiro state. Three novel viruses were present in weed samples collected in Coimbra, Minas Gerais state. One virus was present in tomato samples collected at both locations. Genome features indicate that all six species are typical New World, bipartite begomoviruses. However, the viruses belonging to two of the novel species did not cluster with the Brazilian viruses in a phylogenetic tree. These species could represent a distinct lineage of New World begomoviruses, found in Brazil for the first time.Item Synergism and negative interference during co-infection of tomato and Nicotiana benthamiana with two bipartite begomoviruses(Virology, 2009-03-12) Alves-Júnior, Miguel; Alfenas-Zerbini, Poliane; Andrade, Eduardo C.; Esposito, Débora A.; Silva, Fábio N.; Cruz, Ana Cláudia F. da; Ventrella, Marília C.; Otoni, Wagner C.; Zerbini, F. MuriloIn Brazil, at least eight begomoviruses including Tomato rugose mosaic virus (ToRMV) and Tomato yellow spot virus (ToYSV) infect tomatoes. ToYSV symptoms in tomato and Nicotiana benthamiana appear earlier and are more severe compared to those of ToRMV. We investigated the role of several factors in this differential adaptation. To analyze infection kinetics, a single leaf was inoculated and subsequently detached after different periods of time. Viral DNA accumulation was quantified in plants, viral replication was analyzed in protoplasts, and tissue tropism was determined by in situ hybridization. Results indicate that ToYSV establishes a systemic infection and reaches a higher concentration earlier than ToRMV in both hosts. ToRMV negatively interferes with ToYSV during the initial stages of infection, but once systemic infection is established this interference ceases. In N. benthamiana, ToYSV invades the mesophyll, while ToRMV is phloem-restricted. During dual infection in this host, ToYSV releases ToRMV from the phloem.