Quantitative Analysis of Pathways of Methionine Metabolism and Their Regulation in <i>Lemna</i>

Giovanelli, John; Mudd, S. Harvey; Datko, Anne H.

doi:10.1104/pp.78.3.555

Cited by 118 publications

(85 citation statements)

References 16 publications

(32 reference statements)

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“…It has been suggested that, under normal conditions, the bulk of methionine turnover is involved in these reactions (4). The massive diversion of methionine to ethylene, ACC, and MACC synthesis following TDZ treatment (Table V) could have a dramatic effect on many of these critical metabolic pathways.…”

Section: Discussionmentioning

confidence: 99%

“…After 3 h of incubation in the dark, groups of 10 discs were transferred to flasks containing 1 ml of the inhibitor solution. The flasks were sealed, incubated in the dark (27 ± 1°C), and the ethylene content of the flasks was determined after 4 increase in total EFE activity 1 and 2 d post-treatment. The large response to exogenous ACC by these tissues suggested that endogenous levels of this substrate were in no way saturating.…”

Section: Table IV Effects Of Various Inhibitors On Tdz-induced Ethylenementioning

confidence: 99%

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Cytokinin-Induced Ethylene Biosynthesis in Nonsenescing Cotton Leaves

Suttle

1986

Plant Physiol.

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The influence of cytokinins on ethylene production was examined using cotton leaf tissues. Treatment of intact cotton (Gossypium hirsutum L. cv LG 102) seedlings with both natural and synthetic cytokinins resulted in an increase in ethylene production by excised leaves. The effectiveness of the cytokinins tested was as follows: thidiazuron >> BA >> isopentyladenine 2 zeatin >> kinetin. Using 100 micromolar thidiazuron (TDZ), an initial increase in ethylene production was observed 7 to 8 hours posttreatment, reached a maximum by 24 hours and then declined. Inhibitors of I-aminocyclopropane-l-arboxylic acid (ACC) synthesis and its oxidation to ethylene reduced ethylene production 24 hours post-treatment; however, by 48 hours only inhibitors of ACC oxidation were effective. The increase in ethylene production was accompanied by a massive accumulation of ACC and its acid-labile conjugate. TDZ treatment resulted in a significant increase in the capacity of tissues to oxidize ACC to ethylene. Endogenous levels of methionine remained constant following TDZ treatment. It was concluded that the stimulation of ethylene production in cotton leaves following cytokinin treatment was the result of an increase in both the formation and oxidation of ACC.

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Section: Discussionmentioning

confidence: 99%

Section: Table IV Effects Of Various Inhibitors On Tdz-induced Ethylenementioning

confidence: 99%

Cytokinin-Induced Ethylene Biosynthesis in Nonsenescing Cotton Leaves

Suttle

1986

Plant Physiol.

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“…The pellet was extracted with 3.9 mL methanol:chloroform (2: 1), while the small residue resulting from evaporation of the original supernatant fluid was extracted with a further 0.9 mL of methanol:chloroform (2: 1). After centrifugation, the two supernatants were combined and separated into methanol-water soluble and chloroform-methanol-soluble fractions (3). The two pellets were combined by transfer of the smaller one with methanol washes.…”

Section: Methodsmentioning

confidence: 99%

Phosphatidylcholine Synthesis

Datko

Mudd²

1988

Plant Physiol.

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ABSTRACrThe methylation steps in the biosynthesis of phosphatidylcholine by tissue culture preparations of carrot (Daucus carota L.) and soybean (Glycine max), and by soybean leaf discs, have been studied. Preparations were incubated with tracer concentrations of L-[H3Cqmethionine and the kinetics of appearance of radioactivity in phosphomethylethanolamine, phosphodimethylethanolamine, phosphocholine, phosphatidylmethylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine, methylethanolamine, dimethylethanolamine, and choline followed at short incubation times. With soybean (tissue culture or leaves), an initial methylation utilizes phosphoethanolamine as substrate, forming phosphomethylethanolamine. The latter is converted to phosphatidylmethylethanolamine, which is successively methylated to phosphatidyldimethyethanolamine and to phosphatidylcholine. With carrot, again, an initial methylation is of phosphoethanolamine. Subsequent methylations occur at both the phospho-base and phosphatidyl-base levels. Both of these patterns differ qualitatively from that previously demonstrated in Lemna (SH Mudd, AH Datko 1986 Plant Physiol 82: 126-135) in which all three methylations occur at the phospho-base level. For soybean and carrot, some added contribution from initial methylation of phosphatidylethanolamine has not been excluded. These results, together with those from similar experiments carried out with water-stressed barley leaves (WD Hitz, D Rhodes, AD Hanson 1981 Plant Physiol 68: 814-822) and salinized sugarbeet leaves (AD Hanson, D Rhodes 1983 Plant Physiol 71: 692-700) suggest that in higher plants some, perhaps all, phosphatidylcholine synthesis occurs via a common committing step (conversion of phosphoethanolamine to phosphomethylethanolamine) followed by a methylation pattern which differs from plant to plant.In higher plants the quantitatively dominant utilization of methionine methyl groups is for the synthesis of PtdCho.2 For example, we have shown that, in Lemna paucicostata, the methyls used for this purpose exceed by more than two-fold the total methyls in protein methionine, and are more than the sum of the methyls in all other methylated end products combined (16). Recent studies in this laboratory produced evidence that, in Lemna, the substrates for the methylations involved in PtdCho ' Reprint requests should be addressed to the authors at Building 36, Room 3D06, National Institute of Mental Health, Bethesda, MD 20892.2 Abbreviations: phosphate esters are designated by the prefix, P-(e.g. P-EA or P-Cho); the corresponding phosphatidyl derivatives, by the prefix, Ptd (e.g. PtdEA or PtdCho); and the corresponding glycerylphospho-bases by the prefix, GP-(e.g. GP-EA or GP-Cho). AdoMet, Sadenosyl-L-methionine; EA, ethanolamine; MEA, methylethanolamine; DMEA, dimethylethanolamine; Cho, choline. biosynthesis are almost exclusively water-soluble derivatives of P-EA. Intact plants were incubated under normal growth conditions with methionine labeled with radioactivity in the methyl grou...

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“…SAM is used in a wide variety of biological reactions and is the major hub of Met metabolism (Shen et al, 2002;Martínez-López et al, 2008). Over 80% of the Met is metabolized into SAM, of which 90% is used for transmethylation reactions (Giovanelli et al, 1985). SAM, as a universal methyl group donor, participates in numerous enzyme-catalyzed reactions.…”

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confidence: 99%

S-Adenosylmethionine Synthetase 3 Is Important for Pollen Tube Growth

2016

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ORCID IDs: 0000-0001-6016-5489 (Y.C.); 0000-0001-9106-9385 (S.M.).S-Adenosylmethionine is widely used in a variety of biological reactions and participates in the methionine (Met) metabolic pathway. In Arabidopsis (Arabidopsis thaliana), one of the four S-adenosylmethionine synthetase genes, METHIONINE ADENOSYLTRANSFERASE3 (MAT3), is highly expressed in pollen. Here, we show that mat3 mutants have impaired pollen tube growth and reduced seed set. Metabolomics analyses confirmed that mat3 pollen and pollen tubes overaccumulate Met and that mat3 pollen has several metabolite profiles, such as those of polyamine biosynthesis, which are different from those of the wild type. Additionally, we show that disruption of Met metabolism in mat3 pollen affected transfer RNA and histone methylation levels. Thus, our results suggest a connection between metabolism and epigenetics.

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Quantitative Analysis of Pathways of Methionine Metabolism and Their Regulation in Lemna

Cited by 118 publications

References 16 publications

Cytokinin-Induced Ethylene Biosynthesis in Nonsenescing Cotton Leaves

Cytokinin-Induced Ethylene Biosynthesis in Nonsenescing Cotton Leaves

Phosphatidylcholine Synthesis

S-Adenosylmethionine Synthetase 3 Is Important for Pollen Tube Growth

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