Genetic Manipulation of Isoflavone 7-O-Methyltransferase Enhances Biosynthesis of 4′-O-Methylated Isoflavonoid Phytoalexins and Disease Resistance in Alfalfa

4′-O-Methylation of an isoflavonoid intermediate is a key reaction in the biosynthesis of the phytoalexin medicarpin in legumes. However, isoflavone O-methyltransferase (IOMT) from alfalfa converts the isoflavone daidzein to 7-O-methyl daidzein (isoformononetin) in vitro as well as in vivo in unchallenged leaves of transgenic alfalfa ectopically expressing IOMT. In contrast, elicitation of IOMT-overexpressing plants with CuCl2 or infecting these plants with Phoma medicaginis leads to greater accumulation of formononetin (4′-O-methyl daidzein) and medicarpin in the leaves than does elicitation or infection of control plants, and no isoformononetin is detected. Overexpression of IOMT results in increased induction of phenylpropanoid/isoflavonoid pathway gene transcripts after infection but has little effect on basal expression of these genes. IOMT-overexpressing plants display resistance to P. medicaginis. The apparently different regiospecificities of IOMT in vivo and in vitro are discussed in relation to potential metabolic channeling at the entry point into the isoflavonoid pathway.

[1]  N. Paiva,et al.  Constitutive accumulation of a resveratrol-glucoside in transgenic alfalfa increases resistance to Phoma medicaginis. , 2000, Molecular plant-microbe interactions : MPMI.

[2]  T. Umezawa,et al.  5-Hydroxyconiferyl Aldehyde Modulates Enzymatic Methylation for Syringyl Monolignol Formation, a New View of Monolignol Biosynthesis in Angiosperms* , 2000, The Journal of Biological Chemistry.

[3]  O. Yu,et al.  Identification and expression of isoflavone synthase, the key enzyme for biosynthesis of isoflavones in legumes , 2000, Nature Biotechnology.

[4]  J. Glazebrook,et al.  Arabidopsis PAD3, a Gene Required for Camalexin Biosynthesis, Encodes a Putative Cytochrome P450 Monooxygenase , 1999, Plant Cell.

[5]  R. Dixon,et al.  Molecular characterization of the enzyme catalyzing the aryl migration reaction of isoflavonoid biosynthesis in soybean. , 1999, Archives of biochemistry and biophysics.

[6]  B. Thomma,et al.  Deficiency in phytoalexin production causes enhanced susceptibility of Arabidopsis thaliana to the fungus Alternaria brassicicola. , 1999, The Plant journal : for cell and molecular biology.

[7]  T. Kutchan,et al.  Molecular cloning and functional expression of O-methyltransferases common to isoquinoline alkaloid and phenylpropanoid biosynthesis. , 1999, The Plant journal : for cell and molecular biology.

[8]  B. Thomma,et al.  Separate jasmonate-dependent and salicylate-dependent defense-response pathways in Arabidopsis are essential for resistance to distinct microbial pathogens. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[9]  H. Adlercreutz.  5Epidemiology of phytoestrogens , 1998 .

[10]  U. Sankawa,et al.  Purification of 2-Hydroxyisoflavanone Dehydratase from the Cell Cultures of Pueraria Lobata in Honour of Professor G. H. Neil Towers 75TH Birthday , 1998 .

[11]  R. Ibrahim,et al.  Characterization of two cDNA clones which encode O-methyltransferases for the methylation of both flavonoid and phenylpropanoid compounds. , 1998, Archives of biochemistry and biophysics.

[12]  K. Osakabe,et al.  A novel multifunctional O-methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[13]  R. Dixon,et al.  Affinity chromatography, substrate/product specificity, and amino acid sequence analysis of an isoflavone O-methyltransferase from alfalfa (Medicago sativa L.). , 1996, Archives of biochemistry and biophysics.

[14]  R. Dixon,et al.  High-performance liquid chromatography/continuous-flow liquid secondary ion mass spectrometry of flavonoid glycosides in leguminous plant extracts. , 1996, Journal of mass spectrometry : JMS.

[15]  R. Dixon,et al.  Stress-Induced Phenylpropanoid Metabolism. , 1995, The Plant cell.

[16]  M. Matzke,et al.  How and Why Do Plants Inactivate Homologous (Trans)genes? , 1995, Plant physiology.

[17]  F. Ausubel,et al.  Isolation of phytoalexin-deficient mutants of Arabidopsis thaliana and characterization of their interactions with bacterial pathogens. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[18]  R. Dixon,et al.  Molecular cloning, characterization, and elicitation of acetyl-CoA carboxylase from alfalfa. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[19]  K. Yanagihara,et al.  Antiproliferative effects of isoflavones on human cancer cell lines established from the gastrointestinal tract. , 1993, Cancer research.

[20]  R. Dixon,et al.  Stress responses in alfalfa (Medicago sativa L.). XVIII: Molecular cloning and expression of the elicitor-inducible cinnamic acid 4-hydroxylase cytochrome P450. , 1993, Archives of biochemistry and biophysics.

[21]  H. Kindl,et al.  Disease resistance results from foreign phytoalexin expression in a novel plant , 1993, Nature.

[22]  R. Dixon,et al.  Emerging Strategies for Enhancing Crop Resistance to Microbial Pathogens , 1992, Bio/Technology.

[23]  R. Dixon,et al.  Stress responses in alfalfa (Medicago sativa L.) XVI. Antifungal activity of medicarpin and its biosynthetic precursors; implications for the genetic manipulation of stress metabolites , 1992 .

[24]  H. Adlercreutz,et al.  Urinary excretion of lignans and isoflavonoid phytoestrogens in Japanese men and women consuming a traditional Japanese diet. , 1991, The American journal of clinical nutrition.

[25]  U. Sankawa,et al.  P‐450‐Dependent Oxidative Rearrangement in Isoflavone Biosynthesis: Reconstitution of P‐450 and NADPH:P‐450 Reductase. , 1991 .

[26]  R. Dixon,et al.  Stress Responses in Alfalfa (Medicago sativa L.): X. Molecular Cloning and Expression of S-Adenosyl-l-Methionine:Caffeic Acid 3-O-Methyltransferase, a Key Enzyme of Lignin Biosynthesis. , 1991, Plant physiology.

[27]  U. Sankawa,et al.  P-450-Dependent oxidative rearrangement in isoflavone biosynthesis: Reconstitution of P-450 and NADPH:P-450 reductase , 1991 .

[28]  N. Day,et al.  Dietary effects on breast-cancer risk in Singapore , 1991, The Lancet.

[29]  P. Borst,et al.  Antigenic variation in Trypanosoma brucei: a telomeric expression site for variant-specific surface glycoprotein genes with novel features. , 1991, Nucleic acids research.

[30]  K. Edwards,et al.  A simple and rapid method for the preparation of plant genomic DNA for PCR analysis. , 1991, Nucleic acids research.

[31]  J. Carrington,et al.  Nuclear transport of plant potyviral proteins. , 1990, The Plant cell.

[32]  R. Dixon,et al.  Stress Responses in Alfalfa (Medicago sativa L.): I. Induction of Phenylpropanoid Biosynthesis and Hydrolytic Enzymes in Elicitor-Treated Cell Suspension Cultures. , 1990, Plant physiology.

[33]  R. Kosslak,et al.  Induction of Bradyrhizobium japonicum common nod genes by isoflavones isolated from Glycine max. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[34]  R. Ibrahim,et al.  Enzymology and compartmentation of polymethylated flavonol glucosides in chrysosplenium americanum , 1987 .

[35]  R. Dixon.  THE PHYTOALEXIN RESPONSE: ELICITATION, SIGNALLING AND CONTROL OF HOST GENE EXPRESSION , 1986 .

[36]  G. An,et al.  Development of plant promoter expression vectors and their use for analysis of differential activity of nopaline synthase promoter in transformed tobacco cells. , 1986, Plant physiology.

[37]  G. Kochs,et al.  Enzymic synthesis of isoflavones. , 1986, European journal of biochemistry.

[38]  R. A. Skipp,et al.  Toxic effects of phaseollin on plant cells , 1977 .

[39]  D. Shutt.  The effects of plant oestrogens on animal reproduction. , 1976, Endeavour.

[40]  V. Higgins.  Rôle of the phytoalexin medicarpin in three leaf spot diseases of alfalfa , 1972 .

[41]  R. Dixon.  1.28 – Isoflavonoids: Biochemistry, Molecular Biology, and Biological Functions , 1999 .

[42]  J. Glazebrook,et al.  Arabidopsis PAD 3 , a Gene Required for Camalexin Biosynthesis , Encodes a Putative Cytochrome P 450 Monooxygenase , 1999 .

[43]  R. Dixon,et al.  Molecular Controls for Isoflavonoid Biosynthesis in Relation to Plant and Human Health , 1999 .

[44]  中西 香爾,et al.  Comprehensive natural products chemistry , 1999 .

[45]  H. Adlercreutz.  Epidemiology of phytoestrogens. , 1998, Bailliere's clinical endocrinology and metabolism.

[46]  R. Edwards,et al.  Alfalfa cell cultures treated with a fungal elicitor accumulate flavone metabolites rather than isoflavones in the presence of the methylation inhibitor tubericidin , 1997 .

[47]  J. Kuc.  Phytoalexins, stress metabolism, and disease resistance in plants. , 1995, Annual review of phytopathology.

[48]  R. Welle,et al.  Biosynthesis and metabolism of isoflavones and pterocarpan phytoalexins in chickpea, soybean and phytopathogenic fungi , 1992 .

[49]  R. Dixon,et al.  Isoflavone O-methyltransferase activities in elicitor-treated cell suspension cultures of Medicago sativa☆ , 1991 .

[50]  S. Barnes,et al.  Soybeans inhibit mammary tumors in models of breast cancer. , 1990, Progress in clinical and biological research.

[51]  M. Thomas,et al.  Selection of interspecific somatic hybrids of Medicago by using Agrobacterium-transformed tissues. , 1990 .

[52]  P. S. Matthews,et al.  Phytoalexin detoxification: importance for pathogenicity and practical implications. , 1989, Annual review of phytopathology.

[53]  R. Dixon,et al.  Phytoalexins: enzymology and molecular biology. , 1983, Advances in enzymology and related areas of molecular biology.

[54]  P. Dewick,et al.  Biosynthesis of pterocarpan and isoflavan phytoalexins in Medicago sativa: the biochemical interconversion of pterocarpans and 2′-hydroxyisoflavans , 1979 .

[55]  P. Dewick,et al.  Biosynthesis of pterocarpan, isoflavan and coumestan metabolites of Medicago sativa: chalcone, isoflavone and isoflavanone precursors , 1979 .

[56]  C. A. Thomas,et al.  Molecular cloning. , 1977, Advances in pathobiology.