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1.
Planta ; 237(1): 189-210, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23007552

ABSTRACT

In recent years, there has been a significant increase in the number of completely sequenced plant genomes. The comparison of fully sequenced genomes allows for identification of new gene family members, as well as comprehensive analysis of gene family evolution. The aldehyde dehydrogenase (ALDH) gene superfamily comprises a group of enzymes involved in the NAD(+)- or NADP(+)-dependent conversion of various aldehydes to their corresponding carboxylic acids. ALDH enzymes are involved in processing many aldehydes that serve as biogenic intermediates in a wide range of metabolic pathways. In addition, many of these enzymes function as 'aldehyde scavengers' by removing reactive aldehydes generated during the oxidative degradation of lipid membranes, also known as lipid peroxidation. Plants and animals share many ALDH families, and many genes are highly conserved between these two evolutionarily distinct groups. Conversely, both plants and animals also contain unique ALDH genes and families. Herein we carried out genome-wide identification of ALDH genes in a number of plant species-including Arabidopsis thaliana (thale crest), Chlamydomonas reinhardtii (unicellular algae), Oryza sativa (rice), Physcomitrella patens (moss), Vitis vinifera (grapevine) and Zea mays (maize). These data were then combined with previous analysis of Populus trichocarpa (poplar tree), Selaginella moellindorffii (gemmiferous spikemoss), Sorghum bicolor (sorghum) and Volvox carteri (colonial algae) for a comprehensive evolutionary comparison of the plant ALDH superfamily. As a result, newly identified genes can be more easily analyzed and gene names can be assigned according to current nomenclature guidelines; our goal is to clarify previously confusing and conflicting names and classifications that might confound results and prevent accurate comparisons between studies.


Subject(s)
Aldehyde Dehydrogenase/genetics , Multigene Family , Plant Proteins/genetics , Plants/genetics , Aldehyde Dehydrogenase/metabolism , Aldehydes/metabolism , Animals , Arabidopsis/enzymology , Arabidopsis/genetics , Bryopsida/enzymology , Bryopsida/genetics , Chlamydomonas reinhardtii/enzymology , Chlamydomonas reinhardtii/genetics , Chromosome Mapping , Chromosomes, Plant/genetics , Evolution, Molecular , Genome, Plant/genetics , Genomics/methods , Oryza/enzymology , Oryza/genetics , Plant Proteins/metabolism , Plants/classification , Plants/enzymology , Populus/enzymology , Populus/genetics , Selaginellaceae/enzymology , Selaginellaceae/genetics , Sorghum/enzymology , Sorghum/genetics , Terminology as Topic , Vitis/enzymology , Vitis/genetics , Volvox/enzymology , Volvox/genetics , Zea mays/enzymology , Zea mays/genetics
2.
J Exp Bot ; 63(10): 3887-98, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22442412

ABSTRACT

The Arabidopsis thaliana aldehyde dehydrogenase 3H1 gene (ALDH3H1; AT1G44170) belongs to family 3 of the plant aldehyde dehydrogenase superfamily. The full-length transcript of the corresponding gene comprises an open reading frame of 1583 bp and encodes a protein of 484 amino acid residues. Gene expression studies have shown that this transcript accumulates mainly in the roots of 4-week-old plants following abscisic acid, dehydration, and NaCl treatments. The current study provided experimental data that the ALDH3H1 locus generates at least five alternative transcript variants in addition to the previously described ALDH3H1 mRNA. The alternative transcripts accumulated in wild-type plants at a low level but were upregulated in a mutant that carried a T-DNA insertion in the first exon of the gene. Expression of the transcript isoforms involved alternative gene splicing combined with an alternative promoter. The transcript isoforms were differentially expressed in the roots and shoots and showed developmental stage- and tissue-specific expression patterns. These data support the hypothesis that alternative isoforms produced by gene splicing or alternative promoters regulate the abundance of the constitutively spliced and functional variants.


Subject(s)
Aldehyde Dehydrogenase/genetics , Arabidopsis Proteins/genetics , Arabidopsis/enzymology , DNA, Bacterial/genetics , Gene Expression Regulation, Enzymologic , Aldehyde Dehydrogenase/metabolism , Alternative Splicing , Arabidopsis/genetics , Arabidopsis Proteins/metabolism , Gene Expression Regulation, Plant , Mutagenesis, Insertional , Promoter Regions, Genetic
3.
Front Plant Sci ; 2: 65, 2011.
Article in English | MEDLINE | ID: mdl-22639603

ABSTRACT

Aldehyde dehydrogenases (ALDHs) are a family of enzymes which catalyze the oxidation of reactive aldehydes to their corresponding carboxylic acids. Here we summarize molecular genetic and biochemical analyses of selected ArabidopsisALDH genes. Aldehyde molecules are very reactive and are involved in many metabolic processes but when they accumulate in excess they become toxic. Thus activity of aldehyde dehydrogenases is important in regulating the homeostasis of aldehydes. Overexpression of some ALDH genes demonstrated an improved abiotic stress tolerance. Despite the fact that several reports are available describing a role for specific ALDHs, their precise physiological roles are often still unclear. Therefore a number of genetic and biochemical tools have been generated to address the function with an emphasis on stress-related ALDHs. ALDHs exert their functions in different cellular compartments and often in a developmental and tissue specific manner. To investigate substrate specificity, catalytic efficiencies have been determined using a range of substrates varying in carbon chain length and degree of carbon oxidation. Mutational approaches identified amino acid residues critical for coenzyme usage and enzyme activities.

4.
Biochem J ; 434(3): 459-71, 2011 Mar 15.
Article in English | MEDLINE | ID: mdl-21166653

ABSTRACT

Lipid peroxidation is one of the consequences of environmental stress in plants and leads to the accumulation of highly toxic, reactive aldehydes. One of the processes to detoxify these aldehydes is their oxidation into carboxylic acids catalyzed by NAD(P)+-dependent ALDHs (aldehyde dehydrogenases). We investigated kinetic parameters of two Arabidopsis thaliana family 3 ALDHs, the cytosolic ALDH3H1 and the chloroplastic isoform ALDH3I1. Both enzymes had similar substrate specificity and oxidized saturated aliphatic aldehydes. Catalytic efficiencies improved with the increase of carbon chain length. Both enzymes were also able to oxidize α,ß-unsaturated aldehydes, but not aromatic aldehydes. Activity of ALDH3H1 was NAD+-dependent, whereas ALDH3I1 was able to use NAD+ and NADP+. An unusual isoleucine residue within the coenzyme-binding cleft was responsible for the NAD+-dependence of ALDH3H1. Engineering the coenzyme-binding environment of ALDH3I1 elucidated the influence of the surrounding amino acids. Enzyme activities of both ALDHs were redox-sensitive. Inhibition was correlated with oxidation of both catalytic and non-catalytic cysteine residues in addition to homodimer formation. Dimerization and inactivation could be reversed by reducing agents. Mutant analysis showed that cysteine residues mediating homodimerization are located in the N-terminal region. Modelling of the protein structures revealed that the redox-sensitive cysteine residues are located at the surfaces of the subunits.


Subject(s)
Aldehyde Dehydrogenase/genetics , Arabidopsis Proteins/genetics , Arabidopsis/enzymology , NAD/chemistry , Recombinant Proteins/genetics , Sulfhydryl Compounds/chemistry , Aldehyde Dehydrogenase/chemistry , Amino Acid Substitution , Arabidopsis Proteins/chemistry , Binding Sites , Enzyme Activation , Isoenzymes/chemistry , Isoenzymes/genetics , Kinetics , Mutation , Oxidation-Reduction , Protein Engineering , Protein Multimerization , Recombinant Proteins/chemistry , Stress, Physiological
5.
Planta ; 233(2): 369-82, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21053011

ABSTRACT

Arabidopsis thaliana belongs to those plants that do not naturally accumulate glycine betaine (GB), although its genome contains two genes, ALDH10A8 and ALDH10A9 that code for betaine aldehyde dehydrogenases (BADHs). BADHs were initially known to catalyze the last step of the biosynthesis of GB in plants. But they can also oxidize metabolism-derived aminoaldehydes to their corresponding amino acids in some cases. This study was carried out to investigate the functional properties of Arabidopsis BADH genes. Here, we have shown that ALDH10A8 and ALDH10A9 proteins are targeted to leucoplasts and peroxisomes, respectively. The expression patterns of ALDH10A8 and ALDH10A9 genes have been analysed under abiotic stress conditions. Both genes are expressed in the plant and weakly induced by ABA, salt, chilling (4°C), methyl viologen and dehydration. The role of the ALDH10A8 gene was analysed using T-DNA insertion mutants. There was no phenotypic difference between wild-type and mutant plants in the absence of stress. But ALDH10A8 seedlings and 4-week-old plants were more sensitive to dehydration and salt stress than wild-type plants. The recombinant ALDH10A9 enzyme was shown to oxidize betaine aldehyde, 4-aminobutyraldehyde and 3-aminopropionaldehyde to their corresponding carboxylic acids. We hypothesize that ALDH10A8 or ALDH10A9 may serve as detoxification enzymes controlling the level of aminoaldehydes, which are produced in cellular metabolism under stress conditions.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/enzymology , Betaine-Aldehyde Dehydrogenase/metabolism , Gene Expression Regulation, Plant/physiology , Protein Transport , Stress, Physiological/physiology , Arabidopsis Proteins/genetics , Betaine/metabolism , Betaine-Aldehyde Dehydrogenase/classification , Betaine-Aldehyde Dehydrogenase/genetics , Gene Expression Regulation, Enzymologic/physiology , Mutagenesis, Insertional
6.
Methods Mol Biol ; 639: 282-91, 2010.
Article in English | MEDLINE | ID: mdl-20387053

ABSTRACT

Aldehydes are highly reactive and ubiquitous molecules involved in numerous biochemical processes and physiological responses. Many biologically important aldehydes are metabolized by the superfamily of NAD(P)(+)-dependent aldehyde dehydrogenases [aldehyde:NAD(P)(+) oxidoreductases, EC 1.2.1, ALDH]. Here we describe a straightforward protocol for purification of soluble recombinantly expressed ALDH enzyme based on metal affinity chromatography and the subsequent determination of enzymatic activity using aldehydic substrates, which is assayed spectrophotometrically at 340 nm by conversion of NAD(P)+ to NAD(P)H.


Subject(s)
Aldehyde Dehydrogenase/isolation & purification , Aldehyde Dehydrogenase/metabolism , Chromatography, Affinity/methods , Craterostigma/enzymology , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Electrophoresis, Polyacrylamide Gel , Enzyme Assays , Enzymes, Immobilized/isolation & purification , Escherichia coli , Metals
7.
Plant Cell Environ ; 29(6): 1033-48, 2006 Jun.
Article in English | MEDLINE | ID: mdl-17080931

ABSTRACT

Aldehyde dehydrogenases (ALDHs) play a major role in the detoxification processes of aldehydes generated in plants when exposed to abiotic stress. In previous studies, we have shown that the Arabidopsis thaliana ALDH3I1 gene is transcriptionally activated by abiotic stress, and over-expression of the ALDH3I1 gene confers stress tolerance in transgenic plants. The A. thaliana genome contains 14 ALDH genes expressed in different sub-cellular compartments and are presumably involved in different reactions. The purpose of this study was to compare the potential of a cytoplasmic and a chloroplastic stress-inducible ALDH in conferring stress tolerance under different conditions. We demonstrated that constitutive or stress-inducible expression of both the chloroplastic ALDH3I1 and the cytoplasmic ALDH7B4 confers tolerance to osmotic and oxidative stress. Stress tolerance in transgenic plants is accompanied by a reduction of H2O2 and malondialdehyde (MDA) derived from cellular lipid peroxidation. Involvement of ALDHs in stress tolerance was corroborated by the analysis of ALDH3I1 and ALDH7B4 T-DNA knockout (KO) mutants. Both mutant lines exhibited higher sensitivity to dehydration and salt than wild-type (WT) plants. The results indicate that ALDH3I1 and ALDH7B4 not only function as aldehyde-detoxifying enzymes, but also as efficient reactive oxygen species (ROS) scavengers and lipid peroxidation-inhibiting enzymes. The potential of ALDHs to interfere with H2O2 was also shown for recombinant bacterial proteins.


Subject(s)
Aldehyde Dehydrogenase/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Lipid Peroxidation , Oxidative Stress , Aldehyde Dehydrogenase/analysis , Aldehyde Dehydrogenase/genetics , Arabidopsis/anatomy & histology , Arabidopsis/genetics , Arabidopsis Proteins/analysis , Arabidopsis Proteins/genetics , Chloroplasts/metabolism , Chloroplasts/ultrastructure , Gene Expression Regulation, Plant , Green Fluorescent Proteins/analysis , Mutagenesis, Site-Directed , Mutation , Plants, Genetically Modified/anatomy & histology , Plants, Genetically Modified/drug effects , Plants, Genetically Modified/metabolism , Potassium Chloride/pharmacology , Promoter Regions, Genetic , Recombinant Fusion Proteins/analysis , Sodium Chloride/pharmacology
8.
Plant Mol Biol ; 57(3): 315-32, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15830124

ABSTRACT

Aldehyde dehydrogenase (ALDH) genes have been identified in almost all organisms from prokaryotes to eukaryotes, but particularly in plants knowledge is very limited with respect to their function. The data presented here are a contribution towards a functional analysis of selected Arabidopsis ALDH genes by using expression profiles in wild types and mutants. The Arabidopsis thaliana genome contains 14 genes which represent 9 families. To gain insight into the possible roles of aldehyde dehydrogenases from Arabidopsis, the expression patterns of five selected ALDH genes were analyzed under defined physiological conditions. Three genes (ALDH3I1, 3H1 and ALDH7B4) that belong to two different families are differentially activated by dehydration, high salinity and ABA in a tissue-specific manner. The other two genes (ALDH3F1 and ALDH22A1) are constitutively expressed at a low level. Transcript analysis of ALDH3I1 and ALDH7B4 in Arabidopsis mutants suggests that stress responses are differentially controlled by the phytohormone ABA as well as by pathways that affect sugar metabolism and fatty acid composition of membrane lipids. Our results indicate that the stress-associated ALDH genes participate in several pathways and that their regulation involves diverged signal transduction pathways.


Subject(s)
Aldehyde Dehydrogenase/genetics , Arabidopsis Proteins/genetics , Arabidopsis/genetics , Gene Expression Profiling , Multigene Family/genetics , Abscisic Acid/pharmacology , Amino Acid Sequence , Arabidopsis/enzymology , Cells, Cultured , Cloning, Molecular , DNA, Complementary/chemistry , DNA, Complementary/genetics , Gene Expression Regulation, Enzymologic/drug effects , Gene Expression Regulation, Plant/drug effects , Isoenzymes/genetics , Models, Genetic , Molecular Sequence Data , Mutation , Plant Roots/cytology , Plant Roots/enzymology , Plant Roots/genetics , Plants, Genetically Modified , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Sodium Chloride/pharmacology , Water/pharmacology
9.
Trends Plant Sci ; 9(8): 371-7, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15358267

ABSTRACT

Aldehyde dehydrogenases (ALDHs) represent a protein superfamily of NAD(P)(+)-dependent enzymes that oxidize a wide range of endogenous and exogenous aliphatic and aromatic aldehydes. The Arabidopsis genome contains 14 unique ALDH sequences encoding members of nine ALDH families, including eight known families and one novel family (ALDH22) that is currently known only in plants. Here, we identify members of the ALDH gene superfamily in Arabidopsis; provide a revised, unified nomenclature for these ALDH genes; analyze the molecular relationship among Arabidopsis ALDH genes and compare them to ALDH genes from other species, including prokaryotes and mammals; and describe the role of ALDHs in cytoplasmic male sterility, plant defense and abiotic stress tolerance.


Subject(s)
Aldehyde Dehydrogenase/genetics , Arabidopsis Proteins/genetics , Arabidopsis/genetics , Multigene Family/genetics , Adaptation, Physiological/genetics , Aldehyde Dehydrogenase/metabolism , Aldehyde Oxidoreductases/genetics , Aldehyde Oxidoreductases/metabolism , Arabidopsis/enzymology , Arabidopsis Proteins/metabolism , Fertility/genetics , Immunity, Innate/genetics , Methylmalonate-Semialdehyde Dehydrogenase (Acylating) , Molecular Sequence Data , Phylogeny , Succinate-Semialdehyde Dehydrogenase
10.
Plant J ; 35(4): 452-64, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12904208

ABSTRACT

In plants, oxidative stress is one of the major causes of damage as a result of various environmental stresses. Oxidative stress is primarily because of the excessive accumulation of reactive oxygen species (ROS). The amplification of ROS damage is further stimulated by the accumulation of toxic degradation products, i.e. aldehydes, arising from reactions of ROS with lipids and proteins. Previously, the isolation of dehydration-inducible genes encoding aldehyde dehydrogenases (ALDHs) was reported from the desiccation-tolerant plant Craterostigma plantagineum and Arabidopsis thaliana. ALDHs belong to a family of NAD(P)+-dependent enzymes with a broad substrate specificity that catalyze the oxidation of various toxic aldehydes to carboxylic acids. Analysis of transcript accumulation revealed that Ath-ALDH3 is induced in response to NaCl, heavy metals (Cu2+ and Cd2+), and chemicals that induce oxidative stress (methyl viologen (MV) and H2O2). To investigate the physiological role and possible involvement of ALDHs in stress protection, we generated transgenic Arabidopsis plants overexpressing Ath-ALDH3. Transgenic lines show improved tolerance when exposed to dehydration, NaCl, heavy metals (Cu2+ and Cd2+), MV, and H2O2. Tolerance of transgenic plants is correlated with decreased accumulation of lipid peroxidation-derived reactive aldehydes (as measured by malondialdehyde) compared to wild-type plants. Increased activity of Ath-ALDH3 appears to constitute a detoxification mechanism that limits aldehyde accumulation and oxidative stress, thus revealing a novel pathway of detoxification in plants. We suggest that Ath-ALDH3 could be used to obtain plants with tolerance to diverse environmental stresses.


Subject(s)
Aldehyde Dehydrogenase/physiology , Arabidopsis/physiology , Adaptation, Physiological , Aldehyde Dehydrogenase/genetics , Arabidopsis/enzymology , Arabidopsis/genetics , Cadmium/pharmacology , Copper/pharmacology , Dehydration , Germination , Hydrogen Peroxide/pharmacology , Paraquat/pharmacology , Plants, Genetically Modified , Sodium Chloride/pharmacology
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