Cerato-platanin (CP) and cerato-populin (Pop1) are small proteins produced by the phytopathogenic fungi Ceratocystis platani and C. populicola, respectively. CP and Pop1 behaved as PAMPs, since they elicited typical defense responses in various host and non-host plants. CP and Pop1 are well-structured α/β proteins with a identity of about 63% and the conservative substitution of approximately 12% of amino acids. Also the analysis by circular dichroism showed differences in the secondary structure between the two proteins. The present work aimed to understand whether these structural differences are reflected in differences in their eliciting activity. For this purpose we have used the plane leaves because this is the model on which we work long and know really. In addition to assess the inhibition of fungal growth on plane leaves, we studied the following parameters at 3, 6, 9, 12, 24, 48 hours post treatment: (1) determination and visualization of hydrogen peroxide and nitric oxide by using the specific probe 2’-7’-dichlorodihydrofluorescein diacetate and the fluorescent dye 4,5 diaminofluorescein diacetate, respectively; (2) the viability of cells determined by staining with propidium iodide and the in situ detection of DNA fragmentation (TUNEL assay); (3) the expression of the genes PR5 (thaumatin), LTP (Lipid transfer protein) e APX (Ascorbato perossidasi). All results show marked differences in the eliciting capacity of the two proteins; in particular the plane resistance responses are activated earlier by CP than by Pop1. These results are the basis for identifying the protein region(s) involved in the PAMP activity.
Cerato-platanin and cerato-populin induce differential resistance responses in plane leaves
LOMBARDI, LARA;BERNARDI, RODOLFO;PICCIARELLI, PIERO;
2010-01-01
Abstract
Cerato-platanin (CP) and cerato-populin (Pop1) are small proteins produced by the phytopathogenic fungi Ceratocystis platani and C. populicola, respectively. CP and Pop1 behaved as PAMPs, since they elicited typical defense responses in various host and non-host plants. CP and Pop1 are well-structured α/β proteins with a identity of about 63% and the conservative substitution of approximately 12% of amino acids. Also the analysis by circular dichroism showed differences in the secondary structure between the two proteins. The present work aimed to understand whether these structural differences are reflected in differences in their eliciting activity. For this purpose we have used the plane leaves because this is the model on which we work long and know really. In addition to assess the inhibition of fungal growth on plane leaves, we studied the following parameters at 3, 6, 9, 12, 24, 48 hours post treatment: (1) determination and visualization of hydrogen peroxide and nitric oxide by using the specific probe 2’-7’-dichlorodihydrofluorescein diacetate and the fluorescent dye 4,5 diaminofluorescein diacetate, respectively; (2) the viability of cells determined by staining with propidium iodide and the in situ detection of DNA fragmentation (TUNEL assay); (3) the expression of the genes PR5 (thaumatin), LTP (Lipid transfer protein) e APX (Ascorbato perossidasi). All results show marked differences in the eliciting capacity of the two proteins; in particular the plane resistance responses are activated earlier by CP than by Pop1. These results are the basis for identifying the protein region(s) involved in the PAMP activity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
