“…Although plants are naturally exposed to several phytopathogenic microorganisms, they present tolerance to these pathogens, due to their different structures (cuticles, trichomes, stomata and tyloses) and biochemical mechanisms (such as phenols, phytoalexins, cyanogenic glycosides, protease inhibitors and hydrolases) (Pascholati and Leite, 1994;Oliveira et al, 2003;Caramori et al, 2004). Previous studies have reported that PR proteins are implied in the defense of the plant against viral, bacterial and fungal phytopathogens (Pegg and Young, 1981;Young and Pegg, 1982;Boller, 1987;Boller and Mêtraux 1988;Yun et al, 1987); the PR proteins from families 2 and 3 are β-1,3-glucanases and chitinases, respectively.…”