SELECTIVE INDUCTION OF GLUCOSINOLATES IN OILSEED RAPE LEAVES BY METHYL JASMONATE

Oilseed rape (Brassica napus) plants sprayed with a solution of methyl jasmonate or exposed to methyl jasmonate vapour accumulated indolyl glucosinolates in their leaves in amounts that depended on the concentration applied. At the highest concentration of methyl jasmonate, the total glucosinolate concentration increased up to 20-fold. The predominant components of the response were 3-indolylmethyl- and 1-methoxy-3-indolylmethyl-glucosinolates, which together comprised 90% of the total glucosinolates in treated leaves. This selective induction of indolyl glucosinolates contrasts with the response to fungal infection and to treatment with other abiotic elicitors. The implications of these findings are discussed in terms of the role of both methyl jasmonate and the glucosinolates in plant defence.