EFFECTS OF METHYL JASMONATE AND ELICITOR ON THE ACTIVATION OF PHENYLALANINE AMMONIA-LYASE AND THE ACCUMULATION OF SCOPOLETIN AND SCOPOLIN IN TOBACCO CELL-CULTURES

The effects of methyl jasmonate (MJ) and elicitor on the phenylpropano id metabolism in tobacco was studied. It was found that suspended cell s of tobacco, responded to MJ and elicitor from the plant pathogenic f ungus Fusarium solani with differential formation of phenolic compound s. Both MJ and elicitor induced phenylalanine ammonia-lyase (PAL, EC 4 .3.1.5) activity to comparable levels. Northern hybridization showed t hat the increase in PAL activity was preceded by PAL mRNA accumulation , PAL was induced transcriptionally and enzymatically faster in elicit or-treated cells as compared to MJ-treated cells. HPLC of extracts fro m tobacco cells and their culture filtrate treated with MJ, showed an induction of the syntheses of coumarin-scopoletin and scopolin. This e ffect was not seen in elicitor-treated or control cell cultures. Scopo lin was mainly found within the cell (99%), whereas scopoletin accumul ated in the culture filtrate (90%). We conclude that though MJ mimics stress, indicating its possible role in the plant defense metabolism, responses of tobacco cells to MJ and elicitor are distinct. (C) 1998 E lsevier Science Ireland Ltd. All rights reserved.