Alkaloids in plants and root cultures of Atropa belladonna overexpressing putrescine N‐methyltransferase

• Published in: Journal of experimental botany Vol. 54; no. 390; pp. 2065 - 2070
• Main Authors: Rothe, Grit, Hachiya, Akira, Yamada, Yasuyuki, Hashimoto, Takashi, Dräger, Birgit
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.09.2003; OXFORD UNIVERSITY PRESS; Oxford Publishing Limited (England)
• Subjects: Alkaloids; Atropa belladonna - drug effects; Atropa belladonna - enzymology; Atropa belladonna - genetics; Atropine; Auxins; Belladonna Alkaloids - metabolism; Biological and medical sciences; Biosynthesis; calystegine; Enzymes; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic - drug effects; Gene Expression Regulation, Plant - drug effects; Genome, Plant; hyoscyamine; Indoleacetic Acids - pharmacology; Key words: Atropa belladonna; Leaves; Metabolism; Metabolism. Physicochemical requirements; Methyltransferases - genetics; Nicotiana - enzymology; Nicotiana - genetics; overexpression; Plant physiology and development; Plant roots; Plant Roots - enzymology; Plants; Plants, Genetically Modified; Predetermined motion time systems; putrescine N‐methyltransferase; Recombinant Fusion Proteins - metabolism; Research Papers: Cell and Molecular Biology, Biochemistry and Molecular Physiology; scopolamine; Scopolamine - metabolism; Transgenic plants; tropane alkaloids; Tropanes; Tropanes - metabolism; calystegine; tropane alkaloids; Enzyme; Transferases; Biosynthesis; Gene expression; Nicotiana tabacum; Alkaloid; Methyltransferases; overexpression; Dicotyledones; Putrescine N-methyltransferase; hyoscyamine; Angiospermae; Spermatophyta; Transgenic plant; putrescine Ν-methyltransferase; Solanaceae; Atropa belladonna; scopolamine
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erg227

Putrescine N‐methyltransferase (PMT) is the first alkaloid‐specific enzyme for nicotine and tropane alkaloid formation. The pmt gene from Nicotiana tabacum was fused to the CaMV 35S promoter and integrated into the Atropa belladonna genome. Transgenic plants and derived root cultures were analysed for gene expression and for levels of alkaloids and their precursors. Scopolamine, hyoscyamine, tropine, pseudotropine, tropinone, and calystegines were found unaltered or somewhat decreased in pmt‐overexpressing lines compared to controls. When root cultures were treated with 5% sucrose, calystegine levels were elevated in control roots, but were not affected in pmt‐overexpressing roots. 1 µM auxin reduced calystegine levels in control roots, while in pmt‐overexpressing roots all alkaloids remained unaltered. Expression level of pmt alone is apparently not limiting for tropane alkaloid formation in A. belladonna.