Methyl jasmonate induces a hypersensitive-like response of grapevine in the absence of avirulent pathogens

Methyl jasmonate (MeJA), a common plant secondary compound, when applied to the surface of grapevine leaves, caused the formation of lesions that mimi c a typical hypersensitive response. Sustained exposure of grapevines to 50 muM MeJA provoked tissue damage, stimulated salicylic acid production, and expression of defense-related genes. Besides these local responses, after several days systemic expression of defense-related genes was induced as we ll, Thus, grapevine cells that perceived MeJA generated a cascade of events acting at local, short and long distances and causing the coordinated expr ession of specific defense responses with a timing and magnitude similar to the hypersensitive response against pathogens, MeJA represents a powerful tool to investigate the signals and their respective pathways involved in m echanism of induced disease resistance of grapevine.