Cell wall degrading enzymes, inhibitory proteins, and oligosaccharides participate in the molecular dialogue between plants and pathogens

The wall interface between plants and pathogens plays an important role in the outcome of their interactions. Studying the degradation of plant pectic polysaccharides by microbial pectinases, and of microbial β-glucans by plant glucanases has shown that these polymers are a source of oligosaccharides which elicit defence responses in plants. The extent of degradation appears to be controlled by the presence of inhibitory proteins which counteract enzyme hydrolysis. Thus, plant cell walls participate in the molecular dialogue established between plants and pathogens.