Unlike innate resistance, acquired resistance is a defense system activated
mainly by an earlier infection and allowing plants to resist later attacks by harmful
organisms. Its mode of action does not depend on the direct destruction or inhibition of
the invading pathogen, but rather on physiological changes which lead to the increase
of the physical or chemical barrier of the host plant. The idea of using this ability of
plants to defend themselves, to the aim of protecting them from their bio-aggressors is
a completely realistic strategy that can be reached by using certain molecules, which
have eliciting properties. These molecules, called natural defense stimulators (NDSs),
can be of natural or synthetic origin and are capable of putting the plant on a state of
alert in order to respond quickly and effectively in subsequent attacks. This innovative
strategy greatly contributes to reducing the risks associated with pesticides, and also
has great promises for the future, in terms of both socio-economic impact and
technology transfer. This chapter provides a summary of the remarkable progress made
in recent years in understanding the mechanisms involved in the acquired resistance of
plants to various pathogens.
Keywords: Elicitors of natural plant defense, Induced Systemic Resistance (ISR),
Jasmonic Acid (JA) et Ethylene (ET) signalling, Local Acquired Resistance
(LAR), Pathogenesis-Related (PR) Proteins, Plant growth promoting rhizobacteria
(PGPR), Salicilic Acid signalling, stress memory, Systemic Acquired Resistance
(SAR).