Functional Specialization of Maize Mitochondrial Aldehyde Dehydrogenases
Open Access
- 1 December 2002
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 130 (4) , 1657-1674
- https://doi.org/10.1104/pp.012336
Abstract
The maize (Zea mays) rf2a andrf2b genes both encode homotetrameric aldehyde dehydrogenases (ALDHs). The RF2A protein was shown previously to accumulate in the mitochondria. In vitro import experiments and ALDH assays on mitochondrial extracts from rf2a mutant plants established that the RF2B protein also accumulates in the mitochondria. RNA gel-blot analyses and immunohistolocation experiments revealed that these two proteins have only partially redundant expression patterns in organs and cell types. For example, RF2A, but not RF2B, accumulates to high levels in the tapetal cells of anthers. Kinetic analyses established that RF2A and RF2B have quite different substrate specificities; although RF2A can oxidize a broad range of aldehydes, including aliphatic aldehydes and aromatic aldehydes, RF2B can oxidize only short-chain aliphatic aldehydes. These two enzymes also have different pH optima and responses to changes in substrate concentration. In addition, RF2A, but not RF2B or any other natural ALDHs, exhibits positive cooperativity. These functional specializations may explain why many species have two mitochondrial ALDHs. This study provides data that serve as a basis for identifying the physiological pathway by which the rf2a gene participates in normal anther development and the restoration of Texas cytoplasm-based male sterility. For example, the observations that Texas cytoplasm anthers do not accumulate elevated levels of reactive oxygen species or lipid peroxidation and the kinetic features of RF2A make it unlikely that rf2a restores fertility by preventing premature programmed cell death.Keywords
This publication has 69 references indexed in Scilit:
- Three models of free radical-induced cell injuryPublished by Elsevier ,2002
- A more general mechanism of cytoplasmic male fertility?Trends in Plant Science, 2001
- Identification of Pristanal Dehydrogenase Activity in Peroxisomes: Conclusive Evidence That the Complete Phytanic Acid α-Oxidation Pathway Is Localized in PeroxisomesBiochemical and Biophysical Research Communications, 2001
- Decreased Transcription of a Gene Encoding Putative Mitochondrial Aldehyde Dehydrogenase in Barley (Hordeum vulgare L.) under Submerged Conditions.Plant Biotechnology, 2001
- The molecular basis of cytoplasmic male sterility and fertility restorationTrends in Plant Science, 1998
- Mitochondrial targeting peptides in plantsTrends in Plant Science, 1998
- Inhibition of Recombinant Human Mitochondrial and Cytosolic Aldehyde Dehydrogenases by Two Candidates for the Active Metabolites of DisulfiramBiochemistry, 1997
- SWISS‐MODEL and the Swiss‐Pdb Viewer: An environment for comparative protein modelingElectrophoresis, 1997
- MOLMOL: A program for display and analysis of macromolecular structuresJournal of Molecular Graphics, 1996
- Rapid, Sensitive, and Specific Thiobarbituric Acid Method for Measuring Lipid Peroxidation in Animal Tissue, Food, and Feedstuff SamplesJournal of Agricultural and Food Chemistry, 1994