Control of abscisic acid synthesis.
The abscisic acid (ABA) biosynthetic pathway involves the formation of a 9-cis-epoxycarotenoid precursor. Oxidative cleavage then results in the formation of xanthoxin, which is subsequently converted to ABA. A number of steps in the pathway may control ABA synthesis, but particular attention has been given to the enzyme involved in the oxidative cleavage reaction, i.e. 9-cis-epoxycarotenoid dioxygenase (NCED). Cloning of a gene encoding this enzyme in maize was first reported in 1997. Mapping and DNA sequencing studies indicated that a wilty tomato mutant was due to a deletion in the gene encoding an enzyme with a very similar amino acid sequence to this maize NCED. The potential use of this gene in altering ABA content will be discussed together with other genes encoding ABA biosynthetic enzymes.
Taylor
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IB
Plant Science Division, School of Biosciences, The University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK. ian.taylor@nottingham.ac.uk
Burbidge
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A
Thompson
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AJ
D000040:Abscisic Acid / Q000096:biosynthesis*; D042931:Aldehyde Oxidase; D000445:Aldehyde Oxidoreductases / Q000235:genetics; D049308:Dioxygenases; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D010088:Oxidoreductases / Q000235:genetics; D010105:Oxygenases / Q000235:genetics; D010940:Plant Proteins; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
D010940:Plant Proteins; D000040:Abscisic Acid; D010088:Oxidoreductases; C097153:zeaxanthin epoxidase; D010105:Oxygenases; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase; D000445:Aldehyde Oxidoreductases; D042931:Aldehyde Oxidase