Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
Navegar
5 resultados
Resultados da Pesquisa
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 Quantitative control of Lettuce mosaic virus fitness and host defence inhibition by P1-HCPro(Summa Phytopathologica, 2007-04) Krause-Sakate, Renate; Richard-Forget, Florence; Redondo, Elise; Pavan, Marcelo Agenor; Zerbini, Francisco Murilo; Candresse, Thierry; Gall, Olivier LeTwo Lettuce mosaic virus isolates capable of overcoming the resistance afforded by the resistance gene mo12 in lettuce, LMV-AF199 from Brazil, and LMV-E, an European isolate, were evaluated for the rapidity and severity of symptoms induced on the lettuce variety Salinas 88 (mo12). The mosaic symptoms on Salinas 88 plants inoculated with LMV-AF199 appeared 7 days post-inoculation (dpi) and 15 dpi for LMV-E. The symptoms induced by LMV-AF199 in this cultivar were also more severe than those induced by LMV-E. In order to identify the region of the viral genome responsible for this phenotype, recombinant viruses were constructed between these isolates and the phenotype of each recombinant was analysed. The region encoding proteins P1 and HcPro from LMV-AF199 was associated with the increased virulence in Salinas 88.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 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 Genome-Wide analysis of differentially expressed genes during the early stages of Tomato infection by a Potyvirus(Molecular Plant-Microbe Interactions, 2008-10-27) Alfenas-Zerbini, Poliane; Maia, Ivan G.; Fávaro, Regiane D.; Cascardo, Julio C. M.; Brommonschenkel, Sérgio H.; Zerbini, Francisco MuriloPlant responses against pathogens cause up- and downward shifts in gene expression. To identify differentially expressed genes in a plant-virus interaction, susceptible tomato plants were inoculated with the potyvirus Pepper yellow mosaic virus (PepYMV) and a subtractive library was constructed from inoculated leaves at 72 h after inoculation. Several genes were identified as upregulated, including genes involved in plant defense responses (e.g., pathogenesis-related protein 5), regulation of the cell cycle (e.g., cytokinin-repressed proteins), signal transduction (e.g., CAX-interacting protein 4, SNF1 kinase), transcriptional regulators (e.g., WRKY and SCARECROW transcription factors), stress response proteins (e.g., Hsp90, DNA-J, 20S proteasome alpha subunit B, translationally controlled tumor protein), ubiquitins (e.g., polyubiquitin, ubiquitin activating enzyme 2), among others. Downregulated genes were also identified, which likewise display identity with genes involved in several metabolic pathways. Differential expression of selected genes was validated by macroarray analysis and quantitative real-time polymerase chain reaction. The possible roles played by some of these genes in the viral infection cycle are discussed.