Analysis of the intercellular fluid proteome of Xylella fastidiosa - infected citrus leaves. / Análise do proteoma do fluído intercelular de folhas de laranjeiras infectadas com Xylella fastidiosa.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

In order to understand the mechanisms regulating the Xylella fastidiosacitrus (Citrus sinensis var. Pêra) interaction, proteins with differential accumulation in the apoplast of Xf-infected citrus leaves with or without disease symptoms as compared to non-infected leaves, were identified and characterized using 2D-PAGE and mass spectrometry (MALDI-ToF). The intercellular fluid (IF) was extracted by infiltration and centrifugation from field grown leaves segments. The presence of Xf in the leaves was determined by PCR-amplification of specific DNA fragments. SDS-PAGE was performed in a discontinuous system using equal amounts of IF proteins from non-infected and infected leaves with or without CVC symptoms collected from field grow plants at diferrent locations. Protein profiles were compared using discriminant analyses, based on the relative abundance of each protein. The results indicated that the IF proteome of plants from different localities are distinct, independent of the presence of Xf and/or CVC symptoms. Also, independent of the local where the samples were collected, the IF proteome of non-infected leaves and symptomatic infected leaves were distinct. Using 2D-PAGE it was possible to identify proteins with differential accumulation in the IF of symptomatic and asymptomatic Xf infected citrus leaves, as compared to noninfected controls. The must abundant proteins in the IF showing differential accumulation have apparent molecular mass of 41kDa and pI 4,2-5. The accumulation in the IF asymptomatic Xf infected citrus leaves were 89-129% higher than non-infected controls. Their N-terminal position and the mass spectra of their peptides, after trypsin digestion, are mostly identical, indicating that the are isoforms of the same proteins familiy. N-terminal sequences of the proteins and their internal peptides showed no homology to known genes/proteins in public database, suggesting that these proteins are apoplastic citros specifid proteins, and that they may have a important roles in regulating citrus-Xf interactions.

ASSUNTO(S)

relação planta-patógeno clorose-variegada-dos-citros phytopathogenic bactera plant-pathogen relation orange protein bactéria fitopatogênica proteína laranja citrus variegated chlorosis

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