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

  title={A methyltransferase for synthesis of the phytoalexin 6‐methoxymellein in carrot cells},
  author={Fumiya Kurosaki and Arasuke Nishi},
  journal={FEBS Letters},
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… 
Induction of 6-methoxymellein 6-hydroxymellein production in carrot cells
Changes in pH values at the moment of elicitation of carrot cell suspension cultures influenced the amounts of both phytoalexins synthesized.
Comparison of enzyme activities involved in the biosynthesis of carrot phytoalexin 6-methoxymellein
Abstract Enzyme activities involved in carrot phytoalexin 6-methoxymellein biosynthesis were determined by an improved assay method. Irrespective of the elicitor such as a metal ion, ethylene or
Elicitor induction of enzyme activities and 6-methoxymellein production in carrot cell suspension culture
Fusarium moniliforme endo-polygalacturonase and an elicitor preparation derived from the cell walls of Phythophthora megasperma induced in carrot cell suspension cultures stimulated a marked increase of phenylalanine ammonia-lyase (PAL) activity without affecting chalcone synthase (CHS) activity.
6‐Hydroxymellein synthetase as a multifunctional enzyme complex in elicitor‐treated carrot root extract
Observations suggest that the biosynthesis of 6‐hydroxymellein in carrot cells is catalyzed by an enzyme consisting of a single peptide chain.
Regulation of biosynthesis of carrot phytoalexin 6-methoxymellein
The results suggest that 6MM synthetic enzymes have high affinities for acyl-CoAs and S -adenosyl- l -methionine and preferentially utilize these substrates as compared with other constitutive enzymes.
Derailment product in NADPH-dependent synthesis of a dihydroisocoumarin 6-hydroxymellein by elicitor-treated carrot cell extracts.
This finding suggested that the reduction of the double bond at the 3,4-position of the phytoalexin takes place during the elongation of the poly(oxomethylene) chain.
Partial purification and characterization of 6-hydroxymellein-O-methyltransferase from elicitor-treated carrot cells
Abstract 6-Hydroxymellein-O-methyltransferase (6HMOMT), an inducible OMT involved in the biosynthesis of the carrot phytoalexin 6-methoxymellein (6MM), was partially purified with a 105-fold increase
Transacylase‐like structure and its role in substrate channeling of 6‐hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme in carrot cell extracts
It is suggested that transacylase‐like domain is involved in the structure of 6‐hydroxymellein synthase as a common primary binding site of its co‐substrates, and acetyl and malonyl moieties are properly channeled from their CoA esters to cysteine‐SH and acyl carrier protein‐SH via this domain, respectively.
Biosynthesis of phytoalexin in carrot root requires ethylene action.
The role of ethylene in phytoalexin production by carrot roots was investigated using the ethylene action inhibitor 1-methylcyclopropene (MCP), indicating that 6-ME synthesis by carrot Roots requires ethyleneaction.
Phytoalexin production and cell death in elicited carrot cell suspension cultures
Production of the carrot phytoalexin and its immediate biosynthetic precursor, 6-hydroxymellein, was induced in suspension cultures by biotic elicitors and by the abiotic elicitor HgCl2.


Microsomal isoflavone 2′‐ and 3′‐hydroxylases from chickpea (Cicer arietinum L.) cell suspensions induced for pterocarpan phytoalexin formation
Microsomal fractions derived from suspension‐cultured chickpea (Cicer arietinum L.) cells induced for phytoalexin biosynthesis catalyzed the monohydroxylation of 4′‐methoxyisoflavones (biochanin A
Production and metabolism of 6-methoxymellein in cultured carrot cells
6-Methoxymellein was found to be toxic to the host plant and induced a lag period in the growth of cultured carrot cells at low concentration and caused a rapid decrease in viable cell number when it was added at concentrations higher than 0·5 m m.
A carbon-13 biosynthetic study of stress metabolites from carrot roots: eugenin and 6-methoxymellein
Sodium [1,2-13C2]acetate was readily incorporated into the stress compounds 6-methoxymellein and eugenin after their formation in carrot roots had been induced by treatment with ethrel and confirmed a polyketide origin for both metabolites.
Synthesis of the phytoalexin pisatin by a methyltransferase from pea.
Previous labeling studies in vivo suggest that the terminal step of (+)pisatin biosynthesis in Pisum sativum L. is methylation of the phenol (+)6a-hydroxymaackiain (HMK). We have found that extracts
Isolation of NADPH:isoflavone oxidoreductase, a new enzyme of Pterocarpan phytoalexin biosynthesis in cell suspension cultures of Cicer arietinum
The enzyme data suggest that 2'‐hydroxylation is a prerequisite for the conversion of isoflavones to pterocarpans.
8-hydroxy-6-methoxy-3-methylisocoumarin and other metabolites of ceratocystis fimbriata.
  • A. Stoessl
  • Biology, Medicine
    Biochemical and biophysical research communications
  • 1969
The isolation of the title compound as a metabolite of the mold throws doubt on the role of the corresponding dihydro derivative as a carrot phytoalexin, and the accumulation of large amounts of indole-3-acetic acid may be of significance in the pathogenicity of the Mold.
Dimethylallylpyrophosphate:3,9‐dihydroxypterocarpan 10‐dimethylallyl transferase from Phaseolus vulgaris Identification of the reaction product and properties of the enzyme
A microsomal fraction of elicitor‐challenged bean (Phaseolus vulgaris) cell suspension cultures catalyses the prenylation of DHP to 3,9‐dihydroxy‐10‐dimethylallylpterocarpan (phaseollidin) with dimethylallylpyrophosphate (DMAPP) as the preNyl donor.
Isolation and antimicrobial activity of the phytoalexin 6-methoxymellein from cultured carrot cells
Abstract 6-Methoxymellein was identified as a common phytoalexin produced by carrot roots irrespective of the species of challenging fungi. It was also shown that cultured carrot cells produced
Breakdown of Phosphatidylinositol during the Elicitation of Phytoalexin Production in Cultured Carrot Cells.
Results suggest that breakdown of phosphatidylinositol takes place in the elicitor-treated carrot cells, and the messengers liberated from the phospholipid in the plasma membrane may participate in the elicit process by controlling the activity of protein kinase C-like enzyme(s) and Ca2+-mediated processes including calmodulin.
Induction of phytoalexin synthesis in soybean. Elicitor-induced increase in enzyme activities of flavonoid biosynthesis and incorporation of mevalonate into glyceollin.
The results prove that stimulation of the enzymes of flavonoid biosynthesis and probably glyceollin biosynthesis are caused by the effect of the P. megasperma elicitor and not merely by wounding the plant material.