NMR studies of cerato-populin: investigating the differences in fungal PAMP induced resistance

Plant pathogenic fungi secrete several non-catalytic proteins involved in various aspects of the pathogenesis process. Amongst these, cerato-platanin (CP) was first identified and characterized as a PAMP (pathogen-associated molecular pattern) [1,2]. A sequence homology search revealed a set of fungal Cys-rich secreted proteins that have been grouped in the CP family. They induce synthesis of phytoalexins, overexpression of defense-related genes, H2O2 and NO production, markers of defense activation [3]. The core member of this family, CP (from C. platani) shows a double barrel fold [2]. A CP-orthologous with 73% of similarity, cerato-populin (Pop1), produced by C. populicola , is now under study. Though CP and Pop1 are both host defense inducers, Pop1 shows a slower and weaker defense induction than CP [4]. The aim is the definition of Pop1 NMR-derived solution structure and the characterization of the backbone dynamics of both CP and Pop1. Preliminary studies showed that Pop1 is thermally stable and monomeric. 15N, 13C and 1H resonances have been assigned and the dynamic features will be presented. By comparing the structure and dynamics of CP and Pop1 we expect to obtain useful hints to understand the molecular aspects of Pop1 defense induction activity. [1] Pazzagli et al., Cell Biochem Biophys., 44 (2006), 512 [2] de Oliveira et al., J. Biol. Chem., 286 (2011), 17560 [3] Comparini et al., Appl. Microbiol. Biotechnol., 84 (2009), 309 [4] Martellini et al., Mol. Biotechnol., (2012), in press.