Summary Jasmonates are one of the two primary defense-signaling hormones (salicylates are the others). Plants that are deficient in jasmonate synthesis or signaling are much more susceptible to insect or pathogen damage. Jasmonates are rapidly synthesized in plants subject to wounding, insect biting, or infection by a type of microbial pathogen (necrotroph) that rapidly kills the host cell. The proteins that transduce the jasmonate signal closely resemble those that transduce the auxin signal. Jasmonates also participate in reproductive development and resource allocation.