Fungal metabolites

Extracellular metabolites synthesized by O. ulmi s.l. may help to overcome the natural resistance mechanisms exhibited by the elm tree. In addition, components secreted by the DED fungus may provide soluble products that can be absorbed as food. In general, phytopathogenic fungi produce exo-enzymes in a regulated, orderly fashion, thus enabling a sequential digestion of host materials {[586]}. So far, O. ulmi s.l. has been shown to synthesize a number of extracellular metabolites in vitro and/or in vivo, i.e., glycoproteins, polysaccharides, phenolics, cell wall degrading enzymes, and a hydrophobin. Host phytoalexin production may be induced by the exo enzymes of O. ulmi s.l.