Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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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 Pre-harvest calcium sulfate applications affect vase life and severity of gray mold in cut roses(Scientia Horticulturae, 2005-01-30) Maffia, Luiz A.; Finger, Fernando L.; Batista, Ulisses G.; De Capdeville, GuyGray mold, caused by Botrytis cinerea Pers. Fr., is a major disease in roses. The effect of spraying rose (Cultivar ‘Kiss’) buds with calcium sulfate on the intensity of gray mold was evaluated. Calcium sulfate was sprayed on the buds at different schedules and concentrations before harvest. Thereafter, the buds were harvested and either inoculated or not with B. cinerea. The treatments reduced both the progress and severity of gray mold and increased vase life of the flowers. Good results were achieved with 10 and 20 mM calcium sulfate, applied 24 h before harvest. In the uninoculated assay, the maximum percentages of reduction of the area under the disease progress curve (AUDPC) and of severity were 86% and 86%, respectively, and in the inoculated assay, 68% and 76%, respectively. Vase life of the flowers was increased at least 30% in the assay without inoculation and 20% in the assay with inoculation. Spraying roses with calcium sulfate at 10 mM or 20 mM one day before harvest is recommended to control gray mold after harvest.