Benzoxazinoid biosynthesis

Benzoxazinoids (hydroxamic acids) are plant secondary metabolites that serve as important factors for host resistance against microbial pathogens and insects and for allelopathic effects. They are found in grass family and some eudicot families. The predominant benzoxazinoids are DIBOA and its 7-methoxy derivative DIMBOA, which are stored as glucosides in vacuoles. In maize, benzoxazinoid biosynthesis branches off from tryptophan biosynthesis at indole-3-glycerol phosphate, which is converted to indole by indole-3-glycerol phosphate lyase, BX1. Subsequently four cytochrome P450 monooxygenases (BX2-BX5) catalyze the introduction of four oxygen atoms into the indole moiety, yielding DIBOA. After glucosylation by UDP-glucosyltransferase (BX8/BX9), the glucoside is further modified by hydroxylation and O-methylation at C-7 to form DIMBOA-glucoside.

Metabolism; Biosynthesis of other secondary metabolites

PMID:11106389

Frey M, Stettner C, Pare PW, Schmelz EA, Tumlinson JH, Gierl A.

An herbivore elicitor activates the gene for indole emission in maize.

Proc Natl Acad Sci U S A 97:14801-6 (2000)

PMID:11556781

Gierl A, Frey M.

Evolution of benzoxazinone biosynthesis and indole production in maize.

Planta 213:493-8 (2001)

PMID:16260753

Nomura T, Ishihara A, Yanagita RC, Endo TR, Iwamura H.

Three genomes differentially contribute to the biosynthesis of benzoxazinones in hexaploid wheat.

Proc Natl Acad Sci U S A 102:16490-5 (2005)

PMID:9235894

Frey M, Chomet P, Glawischnig E, Stettner C, Grun S, Winklmair A, Eisenreich W, Bacher A, Meeley RB, Briggs SP, Simcox K, Gierl A.

Analysis of a chemical plant defense mechanism in grasses.

Science 277:696-9 (1997)

PMID:12620350

Frey M, Huber K, Park WJ, Sicker D, Lindberg P, Meeley RB, Simmons CR, Yalpani N, Gierl A.

A 2-oxoglutarate-dependent dioxygenase is integrated in DIMBOA-biosynthesis.

Phytochemistry 62:371-6 (2003)

PMID:11851909

von Rad U, Huttl R, Lottspeich F, Gierl A, Frey M.

Two glucosyltransferases are involved in detoxification of benzoxazinoids in maize.

Plant J 28:633-42 (2001)

PMID:16666853

Bailey BA, Larson RL.

Hydroxamic Acid Glucosyltransferases from Maize Seedlings.

Plant Physiol 90:1071-1076 (1989)

PMID:18192444

Jonczyk R, Schmidt H, Osterrieder A, Fiesselmann A, Schullehner K, Haslbeck M, Sicker D, Hofmann D, Yalpani N, Simmons C, Frey M, Gierl A

Elucidation of the final reactions of DIMBOA-glucoside biosynthesis in maize: characterization of Bx6 and Bx7.

Plant Physiol 146:1053-63 (2008)

PMID:19577780

Frey M, Schullehner K, Dick R, Fiesselmann A, Gierl A

Benzoxazinoid biosynthesis, a model for evolution of secondary metabolic pathways in plants.

Phytochemistry 70:1645-51 (2009)