| Title: | Deciphering systemic wound responses of the pumpkin extrafascicular phloem by metabolomics and stable isotope-coded protein labeling |
| Author(s): | Gaupels F; Sarioglu H; Beckmann M; Hause B; Spannagl M; Draper J; Lindermayr C; Durner J; |
| Address: | "Institute of Biochemical Plant Pathology, Helmholtz Zentrum Munchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany. frank.gaupels@helmholtz-muenchen.de" |
| ISSN/ISBN: | 1532-2548 (Electronic) 0032-0889 (Print) 0032-0889 (Linking) |
| Abstract: | "In cucurbits, phloem latex exudes from cut sieve tubes of the extrafascicular phloem (EFP), serving in defense against herbivores. We analyzed inducible defense mechanisms in the EFP of pumpkin (Cucurbita maxima) after leaf damage. As an early systemic response, wounding elicited transient accumulation of jasmonates and a decrease in exudation probably due to partial sieve tube occlusion by callose. The energy status of the EFP was enhanced as indicated by increased levels of ATP, phosphate, and intermediates of the citric acid cycle. Gas chromatography coupled to mass spectrometry also revealed that sucrose transport, gluconeogenesis/glycolysis, and amino acid metabolism were up-regulated after wounding. Combining ProteoMiner technology for the enrichment of low-abundance proteins with stable isotope-coded protein labeling, we identified 51 wound-regulated phloem proteins. Two Sucrose-Nonfermenting1-related protein kinases and a 32-kD 14-3-3 protein are candidate central regulators of stress metabolism in the EFP. Other proteins, such as the Silverleaf Whitefly-Induced Protein1, Mitogen Activated Protein Kinase6, and Heat Shock Protein81, have known defensive functions. Isotope-coded protein labeling and western-blot analyses indicated that Cyclophilin18 is a reliable marker for stress responses of the EFP. As a hint toward the induction of redox signaling, we have observed delayed oxidation-triggered polymerization of the major Phloem Protein1 (PP1) and PP2, which correlated with a decline in carbonylation of PP2. In sum, wounding triggered transient sieve tube occlusion, enhanced energy metabolism, and accumulation of defense-related proteins in the pumpkin EFP. The systemic wound response was mediated by jasmonate and redox signaling" |
| Keywords: | Adenosine Triphosphate/metabolism Amino Acids/biosynthesis Biological Transport Carbohydrate Metabolism Cucurbita/*metabolism Cyclopentanes/metabolism Energy Metabolism Isotope Labeling/*methods Latex/metabolism Metabolomics/*methods Oxidation-Reduction O; |
| Notes: | "MedlineGaupels, Frank Sarioglu, Hakan Beckmann, Manfred Hause, Bettina Spannagl, Manuel Draper, John Lindermayr, Christian Durner, Jorg eng Research Support, Non-U.S. Gov't 2012/10/23 Plant Physiol. 2012 Dec; 160(4):2285-99. doi: 10.1104/pp.112.205336. Epub 2012 Oct 19" |
