Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/197372
Type: Artigo de periódico
Title: Xylella Fastidiosa Disturbs Nitrogen Metabolism And Causes A Stress Response In Sweet Orange Citrus Sinensis Cv. Pera.
Author: Purcino, Rúbia P
Medina, Camilo Lázaro
Martins de Souza, Daniel
Winck, Flávia Vischi
Machado, Eduardo Caruso
Novello, José Camilo
Machado, Marcos Antonio
Mazzafera, Paulo
Abstract: Xylella fastidiosa (Xf) is a fastidious bacterium that grows exclusively in the xylem of several important crop species, including grape and sweet orange (Citrus sinensis L. Osb.) causing Pierce disease and citrus variegated chlorosis (CVC), respectively. The aim of this work was to study the nitrogen metabolism of a highly susceptible variety of sweet orange cv. 'Pêra' (C. sinensis L. Osbeck) infected with Xf. Plants were artificially infected and maintained in the greenhouse until they have developed clear disease symptoms. The content of nitrogen compounds and enzymes of the nitrogen metabolism and proteases in the xylem sap and leaves of diseased (DP) and uninfected healthy (HP) plants was studied. The activity of nitrate reductase in leaves did not change in DP, however, the activity of glutamine synthetase was significantly higher in these leaves. Although amino acid concentration was slightly higher in the xylem sap of DP, the level dropped drastically in the leaves. The protein contents were lower in the sap and in leaves of DP. DP and HP showed the same amino acid profiles, but different proportions were observed among them, mainly for asparagine, glutamine, and arginine. The polyamine putrescine was found in high concentrations only in DP. Protease activity was higher in leaves of DP while, in the xylem sap, activity was detected only in DP. Bidimensional electrophoresis showed a marked change in the protein pattern in DP. Five differentially expressed proteins were identified (2 from HP and 3 from DP), but none showed similarity with the genomic (translated) and proteomic database of Xf, but do show similarity with the proteins thaumatin, mucin, peroxidase, ABC-transporter, and strictosidine synthase. These results showed that significant changes take place in the nitrogen metabolism of DP, probably as a response to the alterations in the absorption, assimilation and distribution of N in the plant.
Subject: Amino Acids
Citrus Sinensis
Electrophoresis, Gel, Two-dimensional
Nitrates
Nitrogen
Plant Diseases
Plant Leaves
Plant Proteins
Polyamines
Proteome
Xylella
Xylem
Rights: fechado
Identifier DOI: 10.1093/jxb/erm138
Address: http://www.ncbi.nlm.nih.gov/pubmed/17609534
Date Issue: 2007
Appears in Collections:Unicamp - Artigos e Outros Documentos

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