A Unique Short-Chain Dehydrogenase/Reductase in Arabidopsis Glucose Signaling and Abscisic Acid Biosynthesis and Functions

• Published in: The Plant cell 2002-11, Vol.14 (11), p.2723-2743
• Main Authors: Cheng, Wan-Hsing, Endo, Akira, Zhou, Li, Penney, Jessica, Chen, Huei-Chi, Arroyo, Analilia, Leon, Patricia, Nambara, Eiji, Asami, Tadao, Seo, Mitsunori, Koshiba, Tomokazu, Sheen, Jen
• Format: Article
• Language: English
• Subjects: Abscisic Acid - biosynthesis; Abscisic Acid - pharmacology; Abscisic Acid - physiology; Alcohol Oxidoreductases - genetics; Alcohol Oxidoreductases - metabolism; Amino Acid Sequence; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Base Sequence; Biosynthesis; Body size; Chromosome Mapping; Cloning; Cloning, Molecular; Complementary DNA; Dehydrogenase; Enzymes; Ethylenes - biosynthesis; Fertility; Gene expression regulation; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Genetic Complementation Test; Genomics; Glucose - metabolism; Glucose - pharmacology; Molecular Sequence Data; Mutation; Osmotic Pressure - drug effects; Oxidoreductases - metabolism; Phenotypes; Phylogeny; Plant cells; Plant growth; Plant Growth Regulators - biosynthesis; Plant Growth Regulators - pharmacology; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; Plants, Genetically Modified; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; Seedlings; Sequence Homology, Amino Acid; Signal Transduction - drug effects
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.006494

Glc has hormone-like functions and controls many vital processes through mostly unknown mechanisms in plants. We report here on the molecular cloning of GLUCOSE INSENSITIVE1 (GIN1) and ABSCISIC ACID DEFICIENT2 (ABA2) which encodes a unique Arabidopsis short-chain dehydrogenase/reductase (SDR1) that functions as a molecular link between nutrient signaling and plant hormone biosynthesis. SDR1 is related to SDR superfamily members involved in retinoid and steroid hormone biosynthesis in mammals and sex determination in maize. Glc antagonizes ethylene signaling by activating ABA2/GIN1 and other abscisic acid (ABA) biosynthesis and signaling genes, which requires Glc and ABA synergistically. Analyses of aba2/gin1 null mutants define dual functions of endogenous ABA in inhibiting the post-germination developmental switch modulated by distinct Glc and osmotic signals and in promoting organ and body size and fertility in the absence of severe stress. SDR1 is sufficient for the multistep conversion of plastid- and carotenoid-derived xanthoxin to abscisic aldehyde in the cytosol. The surprisingly restricted spatial and temporal expression of SDR1 suggests the dynamic mobilization of ABA precursors and/or ABA.