title: Detection and characterization of protease secreted by the plant pathogen Xylella fastidiosa.
abstract: Xylella fastidiosa is a pathogenic bacterium found in several plants. These bacteria secrete extracellular proteases into the culture broth as visualized in sodium-dodecyl-sulfate polyacrylamide activity gels containing gelatin as a copolymerized substrate. Three major protein bands were produced by the citrus strain with molar masses (MM) of 122, 84 and 65 kDa. Grape strain 9,713 produced two bands of approximately 84 and 64 kDa. These organisms produced zones of hydrolysis in agar plates amended with gelatin, casein and hemoglobin. Gelatin was the best substrate for these proteases. Sodium dodecyl sulfate-polyacrylamide electrophoresis (SDS-PAGE) activity gel indicated that the protease of Xylella fastidiosa from citrus and grape were completely inhibited by PMSF and partially inhibited by EDTA. The optimal temperature for protease activity was 30 degrees C with an optimal pH of 7.0. Among the proteolytic enzymes secreted by the phytopathogen, chitinase and beta-1,3-glucanase activities were also detected in cultures of Xylella fastidiosa (citrus). From these results, it is suggested that proteases produced by strains of Xylella fastidiosa from citrus and grape, belong to the serine- and metallo-protease group, respectively.
authors.affiliation: Laboratório de Biologia Celular e Molecular, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo-CP 96, 13400-970 Piracicaba, SP, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Maria Fedatto
authors.forename: Maria Estela
authors.initials: ME
authors.lastname: Silva-Stenico
authors.forename: Augusto
authors.initials: A
authors.lastname: Etchegaray
authors.forename: Flávia T H
authors.initials: FT
authors.lastname: Pacheco
authors.forename: Jorge L M
authors.initials: JL
authors.lastname: Rodrigues
authors.forename: Siu Mui
authors.initials: SM
authors.lastname: Tsai
mesh_terms: D002688:Chitinases / Q000378:metabolism; D002957:Citrus / Q000382:microbiology; D004492:Edetic Acid / Q000494:pharmacology; D043326:Glucan 1,3-beta-Glucosidase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D010935:Plant Diseases / Q000382:microbiology; D013045:Species Specificity; D013379:Substrate Specificity; D013696:Temperature; D027843:Vitis / Q000382:microbiology; D044167:Xylella / Q000254:growth & development / Q000378:metabolism*
chemical_list: D010664:Phenylmethylsulfonyl Fluoride; D004492:Edetic Acid; D002688:Chitinases; D043326:Glucan 1,3-beta-Glucosidase; D010447:Peptide Hydrolases