ABSTRACT
Toxins produced by phytopathogenic fungi have assumed great importance because of
their involvement in several plant diseases. These pathogeneses have seriously damaged
plants of agrarian, forestal and environmental interest. Frequently, the appearance of
symptoms and the evolution of the disease, observed at distal part of the infection sites,
suggests the involvement of translocable phytotoxins. Considering their social and eco-
nomic impact, many efforts have been made to avoid losses in the agrarian production
and to save the ornamental and forestal plants’ patrimony. Several studies have tried to
understand the role of bioactive microbial metabolites in the pathogenic process and,
therefore, to use them against specific diseases. The chemical nature of these toxins
ranges from low molecular weight compounds, includes all classes of natural products
such as terpenes, chromanones, butenolides, pyrones, macrolides, aromatic derivatives,
amino acids etc., to high molecular compounds such as proteins, glycoproteins and
polysaccharides. As a result, many new phytotoxins, pesticides, fungicides, antibiotics,
plant growth regulators, elicitins and mycotoxins, have been reported (Strobel, 1982;
Graniti et al., 1989; Ballio and Graniti, 1991; Tabacchi, 1994). In some cases, toxins have
been used to obtain products for plant protection or, by genetic selection, plants resis-
tant to specific disease (Durbin, 1981; Graniti et al., 1989; Ballio and Graniti, 1991).
