Early Events in the Signal Pathway for the Oxidative Burst in Soybean Cells Exposed to Avirulent Pseudomonas syringae pv glycinea1
AUTOR(ES)
Rajasekhar, Vinagolu K.
FONTE
American Society of Plant Physiologists
RESUMO
Soybean (Glycine max) cv Williams 82 suspension cultures exhibit an oxidative burst approximately 3 h after challenge with Pseudomonas syringae pv glycinea (Psg) harboring the avrA (avirulence) gene. Pretreatment with the tyrosine (Tyr) kinase inhibitor herbimycin A or the serine/threonine kinase inhibitor K252a abolished the burst and subsequent induction of glutathione S-transferase. However, imposition of a 45-min rest period between pathogen challenge and subsequent addition of the kinase inhibitors resulted in escape from inhibition by herbimycin A, whereas inhibition by K252a persisted. Suramin, a G-protein inhibitor, inhibited the burst if added up to 90 min after pathogen challenge. The burst was also induced by the ion channel generator amphotericin B, and this induction was sensitive to suramin and K252a. Conversely, the ion channel blocker anthracene-9-carboxylate inhibited the Psg:avrA-induced burst. Psg:avrA rapidly induced Tyr phosphorylation of several proteins, and this was inhibited by herbimycin A or anthracene 9-carboxylic acid. These data suggest that the activation of ion channels is followed by an upstream Tyr kinase before the serine/threonine kinase-dependent steps in the signal pathway leading to the oxidative burst. Psg:avrA-dependent induction of phenylalanine ammonia-lyase was not inhibited by herbimycin or suramin, suggesting the operation of different signal pathways for the oxidative burst and phenylpropanoid-derived defense responses.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=59347Documentos Relacionados
- Exopolysaccharides of the phytopathogen Pseudomonas syringae pv. glycinea.
- Copper as a signal for alginate synthesis in Pseudomonas syringae pv. syringae.
- Flagellin Glycosylation Island in Pseudomonas syringae pv. glycinea and Its Role in Host Specificity
- Cloning, Nucleotide Sequence, and Expression in Escherichia coli of Levansucrase Genes from the Plant Pathogens Pseudomonas syringae pv. glycinea and P. syringae pv. phaseolicola
- Characterization and expression of two avirulence genes cloned from Pseudomonas syringae pv. glycinea.