POTENT EFFECT OF JASMONATES ON INDOLE GLUCOSINOLATES IN OILSEED RAPE AND MUSTARD

Jasmonic acid (JA) and methyl jasmonate (MeJA) at nmol doses induced large, sustained, systemic increases (up to 20-fold) in the concentration of specific indole glucosinolates in cotyledons and leaves of oilseed rapes, Brassica napus (3-indolylmethyl) and B. rapa, (4-hydroxy-3-indolylmethyl) and the mustard B.juncea (both). Aliphatic and aromatic glucosinolates in the mustards, B. juncea (allyl) and Sinapis alba (p-hydroxybenzyl) were unaffected by JA. Treatment with JA and MeJA had the same effect on glucosinolates in these species as insect feeding or mechanical wounding. Other substances that may influence wound-, disease-, or stress-induced responses in plants, e.g. abscisic acid, indoleacetic acid, cytokinins, 1-aminocyclopropane-1-carboxylic acid, aminoethoxyvinylglycine, salicylic acid, sucrose, calcium, EGTA, chitin, chitosan and gibberellic acid had no detectable effect on indole glucosinolates. The potency and specificity of the jasmonates indicate a close relationship between JA and/or MeJA and wound-induced changes in indole glucosinolate metabolism in Brassica species.