Evolution of Novel O-methyltransferases from the Vanilla planifolia Caffeic Acid O-methyltransferase

Li, Huaijun Michael; Rotter, David; Hartman, Thomas G.; Pak, F. E.; Havkin‐Frenkel, Daphna; Belanger, Faith C.

doi:10.1007/s11103-006-0029-4

Cited by 32 publications

(30 citation statements)

References 57 publications

(59 reference statements)

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“…Although they can have varied and multiple substrates class II OMTs are still commonly referred to as caffeic acid OMTs as early studies on lignin biosynthesis focused on their ability to methylate this substrate Gowri et al 1991). As well as acting on the lignin precursors caffeic acid and 5-hydroxyferulic acid, class II OMTs have been shown to be involved in the synthesis of a diverse range of secondary metabolites including flavonoids, flavonols, stilbenes, phenylpropenes and various volatile phenolics (Akashi et al 2003;Lavid et al 2002;Li et al 2006;Schmidlin et al 2008;Wein et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Two O-methyltransferases involved in the biosynthesis of methoxypyrazines: grape-derived aroma compounds important to wine flavour

et al. 2010

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Methoxypyrazines (MPs) are volatile, grape-derived aroma compounds that contribute to the distinct herbaceous characters of some wines. Although the full pathway leading to MP production has not been elucidated, there is strong evidence that the final step involves the methylation of non-volatile hydroxypyrazine (HP) precursors. Two cDNA encoding O-methyltransferases (OMTs) that have homology to an enzyme previously purified and shown to catalyse the methylation of HPs were isolated from Cabernet Sauvignon. Recombinant protein from the cDNAs (VvOMT1 and VvOMT2) was produced in E. coli and activity assays demonstrated that both encode OMTs able to methylate HPs to produce MPs, however both showed greatest activity against the flavonol quercetin. VvOMT1 has higher catalytic activity against isobutyl hydroxypyrazine compared to isopropyl hydroxypyrazine, whereas the converse is true for VvOMT2. The timing of the expression of VvOMT1 in the skin and the flesh of developing Cabernet Sauvignon grape berries was associated with the period of MP accumulation in these tissues, while VvOMT2 expression was greatest in roots, which were found to contain high levels of MPs. The MP composition of these tissues also reflects the relative levels of expression of these genes and their substrate preference. The identification of genes responsible for MP production in grapevine will help in understanding the effect of different viticultural and environmental factors on MP accumulation.

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Section: Introductionmentioning

confidence: 99%

Two O-methyltransferases involved in the biosynthesis of methoxypyrazines: grape-derived aroma compounds important to wine flavour

et al. 2010

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“…Progress in cloning of OMTs and the advent of first crystal structures (Zubieta et al, 2001(Zubieta et al, , 2002Gang et al, 2002) revealed that OMTs may have subtle structure-function relationships and are substrate specific. Recently, the evolution of defined substrate requirements was demonstrated for compounds in the scent of V. planifolia (Li et al, 2006). BX7 may represent an OMT with a narrow substrate spectrum.…”

Section: Discussion All Genes Of Benzoxazinone Biosynthesis In Maize mentioning

confidence: 99%

“…for Vanilla planifolia and Rosa spp. OMTs (Scalliet et al, 2002;Li et al, 2006). The pH optimum for the reaction is at 7.0; pH optima of 7 to 8 are often displayed by OMTs (Gang et al, 2002;Lavid et al, 2002).…”

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confidence: 99%

Elucidation of the Final Reactions of DIMBOA-Glucoside Biosynthesis in Maize: Characterization ofBx6andBx7

et al. 2008

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Benzoxazinoids were identified in the early 1960s as secondary metabolites of the grasses that function as natural pesticides and exhibit allelopathic properties. Benzoxazinoids are synthesized in seedlings and stored as glucosides (glcs); the main aglucone moieties are 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA). The genes of DIBOA-glc biosynthesis have previously been isolated and the enzymatic functions characterized. Here, the enzymes for conversion of DIBOA-glc to DIMBOA-glc are identified. DIBOA-glc is the substrate of the dioxygenase BENZOXAZINLESS6 (BX6) and the produced 2,4,7-trihydroxy-2H-1,4-benzoxazin-3-(4H)-one-glc is metabolized by the methyltransferase BX7 to yield DIMBOA-glc. Both enzymes exhibit moderate K m values (below 0.4 mM) and k cat values of 2.10 s 21 and 0.25 s 21 , respectively. Although BX6 uses a glucosylated substrate, our localization studies indicate a cytoplasmic localization of the dioxygenase. Bx6 and Bx7 are highest expressed in seedling tissue, a feature shared with the other Bx genes. At present, Bx6 and Bx7 have no close relatives among the members of their respective gene families. Bx6 and Bx7 map to the cluster of Bx genes on the short arm of chromosome 4.

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“…We have been using an in vitro activity approach to screen candidate OMT genes that encode proteins with such an activity (Pak et al 2004;Li et al 2006). In this study, we generated a cDNA library from the hair cells in developing V. planifolia pods and identified and characterized two cDNAs that encode novel Class I OMTs.…”

Section: Introductionmentioning

confidence: 99%

Functional characterization of two new members of the caffeoyl CoA O-methyltransferase-like gene family from Vanilla planifolia reveals a new class of plastid-localized O-methyltransferases

et al. 2011

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Caffeoyl CoA O-methyltransferases (OMTs) have been characterized from numerous plant species and have been demonstrated to be involved in lignin biosynthesis. Higher plant species are known to have additional caffeoyl CoA OMT-like genes, which have not been well characterized. Here, we identified two new caffeoyl CoA OMT-like genes by screening a cDNA library from specialized hair cells of pods of the orchid Vanilla planifolia. Characterization of the corresponding two enzymes, designated Vp-OMT4 and Vp-OMT5, revealed that in vitro both enzymes preferred as a substrate the flavone tricetin, yet their sequences and phylogenetic relationships to other enzymes are distinct from each other. Quantitative analysis of gene expression indicated a dramatic tissue-specific expression pattern for Vp-OMT4, which was highly expressed in the hair cells of the developing pod, the likely location of vanillin biosynthesis. Although Vp-OMT4 had a lower activity with the proposed vanillin precursor, 3,4-dihydroxybenzaldehyde, than with tricetin, the tissue specificity of expression suggests it may be a candidate for an enzyme involved in vanillin biosynthesis. In contrast, the Vp-OMT5 gene was mainly expressed in leaf tissue and only marginally expressed in pod hair cells. Phylogenetic analysis suggests Vp-OMT5 evolved from a cyanobacterial enzyme and it clustered within a clade in which the sequences from eukaryotic species had predicted chloroplast transit peptides. Transient expression of a GFP-fusion in tobacco demonstrated that Vp-OMT5 was localized in the plastids. This is the first flavonoid OMT demonstrated to be targeted to the plastids.

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Evolution of Novel O-methyltransferases from the Vanilla planifolia Caffeic Acid O-methyltransferase

Cited by 32 publications

References 57 publications

Two O-methyltransferases involved in the biosynthesis of methoxypyrazines: grape-derived aroma compounds important to wine flavour

Two O-methyltransferases involved in the biosynthesis of methoxypyrazines: grape-derived aroma compounds important to wine flavour

Elucidation of the Final Reactions of DIMBOA-Glucoside Biosynthesis in Maize: Characterization ofBx6andBx7

Functional characterization of two new members of the caffeoyl CoA O-methyltransferase-like gene family from Vanilla planifolia reveals a new class of plastid-localized O-methyltransferases

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