Benzoxazinoid biosynthesis in dicot plants

• Published in: Phytochemistry (Oxford) 2008-11, Vol.69 (15), p.2668-2677
• Main Authors: Schullehner, Katrin, Dick, Regina, Vitzthum, Florian, Schwab, Wilfried, Brandt, Wolfgang, Frey, Monika, Gierl, Alfons
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Aphelandra squarrosa; Benzoxazines - metabolism; Benzoxazinoids; Biological and medical sciences; Catalytic Domain; Chemical constitution; Consolida; Consolida orientalis; cytochrome P-450; Cytochrome P-450 Enzyme System - chemistry; Cytochrome P-450 Enzyme System - metabolism; Cytochrome P450 enzyme; DIBOA; DIMBOA; Evolution of secondary metabolism; Fundamental and applied biological sciences. Psychology; Glycerophosphates - metabolism; Indole-3-glycerolphosphate lyase; Lamium galeobdolon; Lyases - chemistry; Lyases - genetics; Lyases - metabolism; Magnoliopsida - metabolism; Models, Molecular; Plant physiology and development; Plant Structures - metabolism; Poaceae - metabolism; secondary metabolites; Staining and Labeling; Structure-Activity Relationship; tissue distribution; Tryptophan synthase alpha-subunit
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2008.08.023

The two initial steps in DIBOA-glucoside biosynthesis are analgous in grasses and in dicots: Indole ist the first intermediate that is oxygenated by a cytochrome P450 enzyme. The indole-3-glycerolphospate lyase CoBX1 evolved independently from ist orthologous function in maize. Benzoxazinoids are common defence compounds of the grasses and are sporadically found in single species of two unrelated orders of the dicots. In the three dicotyledonous species Aphelandra squarrosa, Consolida orientalis and Lamium galeobdolon the main benzoxazinoid aglucon is 2,4-dihydroxy-2 H-1,4-benzoxazin-3(4 H)-one (DIBOA). While benzoxazinoids in Aphelandra squarrosa are restricted to the root, in Consolida orientalis and Lamium galeobdolon DIBOA is found in all above ground organs of the adult plant in concentrations as high as in the seedling of maize. The initial biosynthetic steps in dicots and monocots seem to be identical. Indole is most probably the first specific intermediate that is oxygenated to indolin-2-one by a cytochrome P450 enzyme. C. orientalis has an active indole-3-glycerolphosphate lyase for indole formation that evolved independently from its orthologous function in maize. The properties and evolution of plant indole-3-glycerolphosphate lyases are discussed.