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Plant Mol Biol

Title:		"SAM levels, gene expression of SAM synthetase, methionine synthase and ACC oxidase, and ethylene emission from N. suaveolens flowers"
Author(s):		Roeder S; Dreschler K; Wirtz M; Cristescu SM; van Harren FJ; Hell R; Piechulla B;
Address:		"Department of Biological Sciences, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Strasse 3, Rostock, Germany"
Journal Title:		Plant Mol Biol
Year:		2009
Volume:		20090426
Issue:		5
Page Number:		535 - 546
DOI:		10.1007/s11103-009-9490-1
ISSN/ISBN:		1573-5028 (Electronic) 0167-4412 (Print) 0167-4412 (Linking)
Abstract:		"S'adenosyl-L: -methionine (SAM) is a ubiquitous methyl donor and a precursor in the biosynthesis of ethylene, polyamines, biotin, and nicotianamine in plants. Only limited information is available regarding its synthesis (SAM cycle) and its concentrations in plant tissues. The SAM concentrations in flowers of Nicotiana suaveolens were determined during day/night cycles and found to fluctuate rhythmically between 10 and 50 nmol g(-1) fresh weight. Troughs of SAM levels were measured in the evening and night, which corresponds to the time when the major floral scent compound, methyl benzoate, is synthesized by a SAM dependent methyltransferase (NsBSMT) and when this enzyme possesses its highest activity. The SAM synthetase (NsSAMS1) and methionine synthase (NsMS1) are enzymes, among others, which are involved in the synthesis and regeneration of SAM. Respective genes were isolated from a N. suaveolens petal cDNA library. Transcript accumulation patterns of both SAM regenerating enzymes matched perfectly those of the bifunctional NsBSMT; maximum mRNA accumulations of NsMS1 and NsSAMS1 were attained in the evening. Ethylene, which is synthesized from SAM, reached only low levels of 1-2 ppbv in N. suaveolens flowers. It is emitted in a burst at the end of the life span of the flowers, which correlates with the increased expression of the 1-aminocyclopropane-1-carboxylate oxidase (NsACO)"
Keywords:		"5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase/classification/genetics/metabolism Amino Acid Oxidoreductases/classification/genetics/metabolism Blotting, Northern Cloning, Molecular DNA, Complementary/chemistry/genetics Ethylenes/*metabolism Fl;"
Notes:		"MedlineRoeder, Susanna Dreschler, Katharina Wirtz, Markus Cristescu, Simona M van Harren, Frans J M Hell, Rudiger Piechulla, Birgit eng Research Support, Non-U.S. Gov't Netherlands 2009/04/28 Plant Mol Biol. 2009 Jul; 70(5):535-46. doi: 10.1007/s11103-009-9490-1. Epub 2009 Apr 26"