Cerato-platanin (CP) and cerato-populin (Popl) are small proteins produced by the phytopathogenic fungi Ceratocystis platani and C. populicola, respectively. CP and Popl behaved as PAMPs,since they elicited typical defense responses in various host and non-host plants such as the induction of synthesis of phytoalexins and of some defence related genes. CP and Popl are well-structured α/β proteins with a identity of about 63%. CP structure has been solved by NMR and it is a double ψ-β-barrel protein. Popl has a similar fold but Circular dichroism shows differences in the secondary structure between the two proteins. In order to better characterize the PAMP activity of these proteins we assayed: (i) the production of hydrogen peroxide and nitric oxide by using specific fluorescent probes; (ii) the viability of cells determined by staining with propidium iodide and the in situ detection of DNA fragmentation (TUNEL assay); (iii) the expression of the genes PR5 (thaumatin), LTP (Lipid transfer protein) and APX (Ascorbate peroxidase). Assays were performed using l.5x l0-4M CP and Popl applied on the lower surface of plane leaves. Production of reactive oxygen species (ROS) is a hallmark of successful recognition of infection and activation of plant defences. Results indicate that either CP or Popl induce synthesis of H2O2, NO and hypersensitive cell death with apoptotic features which are hallmark of successful recognition of infection and activation of plant defences. H2O2 is produced after 3-6 hours of treatment and it remains constant until 24-48 hours post-treatment when the programmed cell deathbegan. NO is produced as a spike between 6 and 9 hours when the analyzed genes are over-expressed (PRl and APX) or under-expressed (LTP). Moreover, Popl effects are delayed when compared to the CP ones. The differences between CP and Popl effects will be interpreted in the light of structural differences, being the 3D structure of CP recently determined.

Cerato-platanin and cerato-populin induce defence responses in plane leaves

LOMBARDI, LARA;BERNARDI, RODOLFO;PICCIARELLI, PIERO;
2011

Abstract

Cerato-platanin (CP) and cerato-populin (Popl) are small proteins produced by the phytopathogenic fungi Ceratocystis platani and C. populicola, respectively. CP and Popl behaved as PAMPs,since they elicited typical defense responses in various host and non-host plants such as the induction of synthesis of phytoalexins and of some defence related genes. CP and Popl are well-structured α/β proteins with a identity of about 63%. CP structure has been solved by NMR and it is a double ψ-β-barrel protein. Popl has a similar fold but Circular dichroism shows differences in the secondary structure between the two proteins. In order to better characterize the PAMP activity of these proteins we assayed: (i) the production of hydrogen peroxide and nitric oxide by using specific fluorescent probes; (ii) the viability of cells determined by staining with propidium iodide and the in situ detection of DNA fragmentation (TUNEL assay); (iii) the expression of the genes PR5 (thaumatin), LTP (Lipid transfer protein) and APX (Ascorbate peroxidase). Assays were performed using l.5x l0-4M CP and Popl applied on the lower surface of plane leaves. Production of reactive oxygen species (ROS) is a hallmark of successful recognition of infection and activation of plant defences. Results indicate that either CP or Popl induce synthesis of H2O2, NO and hypersensitive cell death with apoptotic features which are hallmark of successful recognition of infection and activation of plant defences. H2O2 is produced after 3-6 hours of treatment and it remains constant until 24-48 hours post-treatment when the programmed cell deathbegan. NO is produced as a spike between 6 and 9 hours when the analyzed genes are over-expressed (PRl and APX) or under-expressed (LTP). Moreover, Popl effects are delayed when compared to the CP ones. The differences between CP and Popl effects will be interpreted in the light of structural differences, being the 3D structure of CP recently determined.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/144514
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