ABSTRACT
Plant cell wall is the first barrier and penetration of the cell wall appears to be the first
requirement for the pathogenesis of fungal pathogens (Thordal-Christensen, 2003; D’Ovidio
et al., 2004). The cell walls are complex amalgams of carbohydrates (cellulose, hemicellulose,
and pectic polysaccharides), proteins, lignin, and incrusting substances such as cutin, suberin,
and certain inorganic compounds (Showalter, 1993; Chaco´n-Martı´nez et al., 2004). Cuticle is
the incrusting substance and it forms the first layer covering the outer walls of epidermal cells
(Gevens and Nicholson, 2000). Fungal pathogens are able to produce a variety of enzymes
degrading the plant cell wall, and these enzymes help the pathogens in penetration and
colonization of their host plants (Chaco´n-Martı´nez et al., 2004; Herbert et al., 2004; Espino
et al., 2005; Yang et al., 2005). The degraded wall components may signal the bulk production
of these cell wall-degrading enzymes and aggravate the disease incidence (Kemp et al., 2004;
Chassot and Metraux, 2005).
