QUANTIFICATION, CORRELATIONS AND MANIPULATIONS OF WOUND-INDUCED CHANGES IN JASMONIC ACID AND NICOTINE IN NICOTIANA-SYLVESTRIS

Jasmonic acid (JA) is thought to be part of a signal-transduction path way which dramatically increases de-novo nicotine synthesis in the roo ts and increases whole-plant (WP) nicotine pools in response to the wo unding of the leaves in Nicotiana sylvestlis-Spegazzini and Comes (Sol anaceae) We report the synthesis of a doubly labeled JA ([1, 2-(13) C] JA) and use it as an internal standard to quantify by gas chromatograp hy-mass spectrometry the changes in root and shoot JA pools in plants subjected to differing amounts of standardized leaf wounding. Wounding increased JA pools 10-fold locally in damaged leaves within 90 min an d systemically in the roots (3.5-fold) 180 min after wounding. If JA f unctions as an intermediary between stimulus and response, quantitativ e relationships among the stimulus, JA, and the response should exist. To examine these relationships, we varied the number of punctures in four leaves and quantified both the resulting JA in damaged leaves aft er 90 min and the resulting WP nicotine concentration after 5 d. We fo und statistically significant, positive relationships among number of leaf punctures, endogenous JA, and WP nicotine accumulation. We used t wo inhibitors of wound-induced nicotine production, methyl salicylate and indole-3-acetic acid, to manipulate the relationships between woun d-induced changes in JA and WP nicotine accumulation. Since wounding a nd the response to wounding occur in widely separated tissues, we appl ied inhibitors to different plant parts to examine their effects on th e local and systemic components of this response. In all experiments, inhibition of the wound-induced increase in leaf JA 90 min after wound ing was associated with the inhibition of the nicotine response 5 d af ter wounding. We conclude that wound-induced increases in leaf JA are an important component of this long-distance signal-transduction pathw ay.