Xanthomonas spp. causadoras de mancha bacteriana do tomateiro (Lycopersicon esculentum Mill.): detecção em sementes e diferenciação / Xanthomonas spp. causing the tomato (Lycopersicon esculentum Mill.) bacterial spot: detection in seeds and differentiation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The tomato is the second economical important horticultural crop in the world, being one of the most exigent cultures in phytosanitary cares, due to the large number of diseases that attack the culture and for the high destructive capacity and difficult control of the pathogens. The bacterial-spot, caused by species of the genus Xanthomonas (X. euvesicatoria, X. gardneri, X. vesicatoria and X. perforans), is one of the most important tomato diseases, affecting plant in any development stage, being able to occur in all aerial part, provoking reduction in quantity and quality of the production. To reduce the pathogen dissemination and to determine control measures in the cultivation areas, it is important that the pathogen detection in plants and seeds has been efficient. So, it is necessary to carry out analysis to detect bacteria in seeds, especially when the infection level or incidence is very low. The objective of this work was to develop detection and differentiation methods of Xanthomonas spp. in tomato seeds. A semi-selective medium was developed, constituted by dextrose (5,0 g/L), NaCl (5,0 g/L), KH2PO4 (1,4 g/L), K2HPO4 (3,6 g/L), meat extract (1,0 g/L), peptone (5,0 g/L), yeast extract (2,0 g/L), cefaclor (40,0 mg/L), nistatine (50,0 mg/L), benomyl (10,0 mg/L) and agar (14,0 g/L), wich showed low repressivity to the Xanthomonas spp. and moderate supressivity to the non-target microorganisms associated to tomato seeds and high sensibility, besides low cost. By PCR-RFLP of a rpoB gene fragment, it was possible to differentiate the species of the tomato bacterial-spot.

ASSUNTO(S)

bacterial-spot mancha bacteriana tomato genes meios de cultura seeds fitossanidade culture media polymerase chain reaction reação em cadeia por polimerase genes bactéria fitopatogênica sementes tomate phytosanity phytopathogenic bacterium

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