Biogenetic implication of lupin alkaloid biosynthesis in bitter and sweet forms of Lupinus luteus and L. albus

• Published in: Phytochemistry (Oxford) Vol. 34; no. 4; pp. 1041 - 1044
• Main Authors: Saito, Kazuki, Koike, Youichi, Suzuki, Hideyuki, Murakoshi, Isamu
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 1993; Elsevier
• Subjects: acyltransferases; Agronomy. Soil science and plant productions; alkaloids; Biological and medical sciences; biosynthesis; bitter lupin; enzyme activity; Fundamental and applied biological sciences. Psychology; L. albus; Leguminosae; lupin; Lupinus albus; Lupinus luteus; Metabolism; Metabolism. Physicochemical requirements; Plant physiology and development; quinolizidine alkaloid; sweet lupin; sweet lupin; Leguminosae; lupin; biosynthesis; quinolizidine alkaloid; bitter lupin; Lupinus luteus; L. albus; Acyltransferases; Enzyme; Transferases; Interspecific comparison; Biosynthesis; Grain legume; Alkaloid; Enzymatic activity; Quinolizine derivatives; Dicotyledones; Angiospermae; Lupinus albus; Spermatophyta; Fodder crop
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/S0031-9422(00)90709-X

The concentrations of lupin alkaloids, l-lysine and cadaverine were determined by a capillary GC-MS and an amino acid analyser in bitter and sweet plants of Lupinus luteus and L. albus. The contents of total crude alkaloids were ca four-fold higher in bitter plants than those in sweet plants; by contrast, the alkaloid patterns were similar in bitter and sweet plants. However, the cellular concentrations of l-lysine and cadaverine, a precursor amino acid and a decarboxylated intermediate for biosynthesis of the alkaloids, did not differ markedly between bitter and sweet plants. The enzymatic activities of acyltransferases for formation of (-)- p-coumaroyllupinine and (+)- 13α-tigloyloxylupanine were also the same in the cell-free extracts of bitter and sweet plants. These results suggest that the biosynthetic steps of ring closure forming initial cyclic alkaloids such as (-)-lupinine and (+)-lupanine from cadaverine are blocked in sweet plants, but the steps prior to cadaverine and the later steps for modification of the cyclized alkaloids are not altere