3-Hydroxy-3-methylglutaryl coenzyme A reductase activity in the endosperm of maize vivipary mutants

During seed maturation the levels of the rate-limiting enzyme of isoprenoid biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) decrease while the levels of the isoprenoid compound abscisic acid (ABA) increase. In the present study, we demonstrate that HMGR specific activity is inve...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1994-05, Vol.105 (1), p.119-125
Main Authors: Moore, K.B, Oishi, K.K
Format: Article
Language:English
Subjects:
ACIDE ABSCISSIQUE
ACIDO ABSCISICO
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
BIOSINTESIS
BIOSYNTHESE
Biosynthesis
Corn
Development and Growth Regulation
Embryos
Endosperm
ENDOSPERMA
ENDOSPERME
Gene expression regulation
Germination
GRAINE
LIPIDE
LIPIDOS
METABOLITE
METABOLITOS
MUTANT
MUTANTES
Plants
Seed development
SEMILLA
Terpenoids
VARIACION GENETICA
VARIATION GENETIQUE
VIA BIOQUIMICA DEL METABOLISMO
Vivipary
VOIE BIOCHIMIQUE DU METABOLISME
ZEA MAYS
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Summary:During seed maturation the levels of the rate-limiting enzyme of isoprenoid biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) decrease while the levels of the isoprenoid compound abscisic acid (ABA) increase. In the present study, we demonstrate that HMGR specific activity is inversely correlated with endogenous ABA levels in Zea mays endosperm during seed development. HMGR specific activity and ABA levels were measured in the endosperm of the maize vivipary mutants vp2, vp5, and vp7, which are defective in ABA biosynthesis, and vp1, which is defective in an ABA response element. Reduced ABA levels were observed in the endosperm of vp2, vp5, and vp7, whereas HMGR activity levels were higher compared with wild-type sibling endosperm activity. HMGR activities were increased by as much as 37% (vp2), 45% (vp5), and 58% (vp7) in the mutants. Endosperm HMGR activity in the vp1 mutant was also increased (41%) relative to wild-type siblings, even though vp1 does not have reduced ABA levels. In addition, exogenous ABA inhibits HMGR activity 34 to 50% in maize roots. These results suggest that HMGR activity levels during seed development are regulated via a Vp1-dependent signal transduction pathway that is affected by the reduced ABA content of vp2, vp5, and vp7 endosperm
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.105.1.119