Cerato-platanin (CP) is a protein elicitor produced by Ceratocystis platani, the causal agent of canker stain of plane tree. The eliciting activity of CP has been extensively studied, and in accordance with the “zig-zag model” described by Jones and Dangl (2006), CP may be considered a PAMP (pathogen-associated molecular pattern). However, the primary role of CP and of all the other proteins of the “cerato-platanin family” in fungi is unknown. CP is both a structural component of the cell wall of C. platani and a protein secreted in the medium where the fungus grows. No lytic activity has ever been reported. Recently, by studying the three-dimensional structure of the protein and the pattern of gene expression, a clue on its role has been found: CP could act in the remodelling and enlargement of the cell wall during hyphal growth and in the formation of chlamydospores, with a role like that of expansins. In the present work, the expansinlike activity of CP was investigated. Like expansins, CP was able to disrupt filter paper in a concentration-dependent manner and to cause fragmentation of the crystalline cellulose Avicel. Cotton fibers incubated for 24 h with CP, then sonicated, showed breakage and defibration, whereas fibers incubated in buffer alone remained undamaged. Optimum of pH and temperature for CP activity were determined. Results strongly suggest that CP may be a new fungal expansin. Its possible synergistic effect with cellulases is under investigation.
Cerato-platanin shows expansin-like activity on cellulosic materials.
BERNARDI, RODOLFO;
2012-01-01
Abstract
Cerato-platanin (CP) is a protein elicitor produced by Ceratocystis platani, the causal agent of canker stain of plane tree. The eliciting activity of CP has been extensively studied, and in accordance with the “zig-zag model” described by Jones and Dangl (2006), CP may be considered a PAMP (pathogen-associated molecular pattern). However, the primary role of CP and of all the other proteins of the “cerato-platanin family” in fungi is unknown. CP is both a structural component of the cell wall of C. platani and a protein secreted in the medium where the fungus grows. No lytic activity has ever been reported. Recently, by studying the three-dimensional structure of the protein and the pattern of gene expression, a clue on its role has been found: CP could act in the remodelling and enlargement of the cell wall during hyphal growth and in the formation of chlamydospores, with a role like that of expansins. In the present work, the expansinlike activity of CP was investigated. Like expansins, CP was able to disrupt filter paper in a concentration-dependent manner and to cause fragmentation of the crystalline cellulose Avicel. Cotton fibers incubated for 24 h with CP, then sonicated, showed breakage and defibration, whereas fibers incubated in buffer alone remained undamaged. Optimum of pH and temperature for CP activity were determined. Results strongly suggest that CP may be a new fungal expansin. Its possible synergistic effect with cellulases is under investigation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
