Caracterização morfológica de cercospora e eficiência da toxina cercosporina na seleção de genótipos de pimenteiras ornamentais

• Autor(a) principal: Santos, Aline da Silva
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/14683
• topic: Capsicum annuum; Cercospora capsici; Avaliação de genótipos; Pimenteiras ornamentais - Doenças; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA

The Cercospora leaf spot is an serious fungal disease of plants of the genus Capscum, it is caused by fungi of genus Cercospora, which produce a toxin, the cercosporin, that has a red coloration which is very toxic to the plant tissues. Therefore, this work purpose was realize a characterization of this disease in ornamental chili plants, as well as, try the efficiency of cercosporin toxin in the genotype of chili ornamental plants. Therefore, it has proceeded an organs collet of infected organs by ornamental chili plants grown in a greenhouse, located in the Science Center Agrarian of Federal University of Paraíba – UFPB/CCA, Campus II, Areia – PB. The samples were taken to the Biotechnology Laboratory of UFPB/CCA for a morphological characterization of the fungus. The disease characterization was did observing plants with symptoms of the disease. To test the efficiency of the cercosporin, it was realized an induction of the production of cercosporin in fungi colonies grown in different in various culture media having as the base coconut milk (LCO), coconut water (ACO), V8 juice (A- V8), leaf extract of pepper (A – P), and water agar (A-A). After that, the toxin was identified throw de change of coloration to green of the fungal solution in contact with the alkaline way, KOH 5N. After this moment of identification, it was realized a quantification and an extraction of cercosporin with the aid of extractor solution Tris-HCl that has pH 6,8. The toxin quantification was made using the Bradford method, proceeding its inoculation in leaves of seven genotypes of chili plants using the concentration that best expressed the symptoms. When the results was analyzed, it has observed that fungous structure was the same kind of the description of the cercospora capsici fungi, which is the responsible for the Cercospora leaf spot has said the Koch postulate. Direct isolation method has given the possibility the achievement of fungus in all plants parts, and, the indirect method have given possibility it with the branches. The water agar base way has promote a bigger mycelial growth, and the leaf extract base way improve a bigger colony proportion. The ACO way has promote the toxin expansion in all Petri dish and has have a bigger quantity of cercosporin for mycelial disc. All the way, except the A-A, has induced a cercosporin produce. The coconut milk base way and the leaf extract with and without gelling present the biggest cercosporina production. The isolated grown in the A-A way has produced quantities of cercosporin equal the isolated grown in the LCO and P-A ways with gelling. The toxin concentrations 40% and 50% showed better the cercosporin symptoms. The UFPB 131, UFPB 132, and UFPB 358 has showed tolerance to the cercosporin toxin.