A methyltransferase for synthesis of the phytoalexin 6-methoxymellein in carrot cells

Abstract

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Carrot ( Daucus carota L.) roots treated with 2-chloroethylphosphonic acid or uronide elicitor accumulated the phytoalexin 6-methoxymellein. The extracts of these cells catalyzed methylation of 6-hydroxymellein to 6-methoxymellein with S-adenosyl-L-methionine as a methyl donor. Activity of the O-methyltransferase was not found in fresh carrot roots but increased when they were treated with either type of elicitor in parallel with the increase in 6-methoxymellein content. The enzyme did not methylate 6-methoxymellein, 3,4-dehydro-6-methoxymellein, and some coumarin derivatives, though 3,4-dehydro-6-hydroxymellein accepted methyl moiety at the same rate as in 6-hydroxymellein.

Publication:

FEBS Letters

Pub Date:

January 1988

DOI:

10.1016/0014-5793(88)80894-9

Bibcode:

1988FEBSL.227..183K

Keywords:

• O-Methyltransferase;
• 6-Methoxymellein;
• Phytoalexin;
• Dihydroisocoumarin;
• ( Daucus carota L.)