Caracterização morfológica e bioquímica de isolados de Clavibacter michiganensis subsp. michiganensis e avaliação de meios semi-seletivos para sua detecção

• Autor(a) principal: Lima, Hyanameyka Evangelista de
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4362
• topic: Clavibacter michiganensis subsp. michiganensis; Morfologia; Cultura e meios de cultura; Metabolismo; Inoculação; Clavibacter michiganensis subsp. michiganensis; Morphology; Culture and culture media; Metabolism; Innoculation; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA

Six semi-selective media used for detection of Clavibacter michiganensis subsp. michiganensis (Cmm), developed elsewhere and reported in international literature, were evaluated for their efficacy to recover 20 Cmm isolates collected in different regions of Brazil. From these, only MB1M, D2ANX, and KBT allowed the growth of Cmm isolates, thus indicating differential resistance of Brazilian isolates to the antimicrobials used in the semi-selective media. Because they restrict the pathogen, the media SCM, mSCM and DCNS cannot be used for epidemiological studies in Brazil, such as detection on seed lots. MB1M, D2ANX and KBT also proved to be suppressive to contaminants associated with three tomato seed samples and two tomato leaf samples. The morphological characterization of colonies of each isolated was performed in these semi-selective media in comparison with the 523 media (Kado & Heskett, 1970). There was variation in the size, color and necessary time for formation of the colonies in the different semi-selective media. However, the typical characteristics of the colonies, as circular form, raised surface, smooth texture and smooth edges had been same for all the isolates, in all the semi-selective media. Thus, the format of colonies is a solid characteristic for the identification of Cmm. The biochemical tests proved to be useful to detect variability among the Brazilian isolates, as well among other isolates reported in the literature. The characteristics which showed consistency could be recommended for confirmation of the identity of Cmm isolates. In a complementary study, hypersensitivity reaction (HR) of all 20 Cmm isolates were positive on Mirabilis jalapa and Phaseolus vulgaris, but not on Coffea arabica.