SIGNALING IN THE ELICITATION PROCESS IS MEDIATED THROUGH THE OCTADECANOID PATHWAY LEADING TO JASMONIC ACID

Fungal cell walls and fragments thereof (elicitors) induce the formati on of low and high molecular weight defense compounds in plant cell su spension cultures. This induced synthesis requires a signal molecule t ransmitting the message between the elicitor plant cell wall receptor and gene activation. We demonstrate in this study that cis-jasmonic ac id is rapidly synthesized in plant cell cultures of diverse taxonomic origin (gymnosperms and mono- and dicotyledonous plants) after challen ge with a fungal elicitor preparation. The rapid decline of cis-jasmon ic acid in some of these tissues is attributed to rapid metabolism of this pentacyclic acid. The induction of alkaloids by several different molecules provoking the elicitation process is strictly correlated wi th the synthesis of jasmonates. Elicitation leads to a rapid release o f alpha-linolenic acid from the lipid pool of the plant cell. Alpha-li nolenic acid and 12-oxophytodienoic acid, the formation of which is al so induced, are known to be distant precursors of jasmonic acid. We as sume cis-jasmonic acid and its precursors to be the signaling molecule s in the elicitation process.