Colonization of Solanum melongena and Vitis vinifera Plants by Botrytis cinerea Is Strongly Reduced by the Exogenous Application of Tomato Systemin

Plant defense peptides are able to control immune barriers and represent a potential novel
resource for crop protection. One of the best-characterized plant peptides is tomato Systemin (Sys)
an octadecapeptide synthesized as part of a larger precursor protein. Upon pest attack, Sys interacts
with a leucine-rich repeat receptor kinase, systemin receptor SYR, activating a complex intracellular
signaling pathway that leads to the wound response. Here, we demonstrated, for the first time,
that the direct delivery of the peptide to Solanum melongena and Vitis vinifera plants protects from the
agent of Grey mould (Botrytis cinerea). The observed disease tolerance is associated with the increase
of total soluble phenolic content, the activation of antioxidant enzymes, and the up-regulation of
defense-related genes in plants treated with the peptide. Our results suggest that in treated plants,
the biotic defense system is triggered by the Sys signaling pathway as a consequence of Sys interaction
with a SYR-like receptor recently found in several plant species, including those under investigation.
We propose that this biotechnological use of Sys, promoting defense responses against invaders,
represents a useful tool to integrate into pest management programs for the development of novel
strategies of crop protection.