Plant ALDH10 family members are aminoaldehyde dehydrogenases (AMADHs), which oxidize ω-aminoaldehydes to the corresponding acids. They have been linked to polyamine catabolism, osmoprotection, secondary metabolism (fragrance), and carnitine biosynthesis. Plants commonly contain two AMADH isoenzymes. We previously studied the substrate specificity of two AMADH isoforms from peas (PsAMADHs). Here, two isoenzymes from tomato (Solanum lycopersicum), SlAMADHs, and three AMADHs from maize (Zea mays), ZmAMADHs, were kinetically investigated to obtain further clues to the catalytic mechanism and the substrate specificity. We also solved the high resolution crystal structures of SlAMADH1 and ZmAMADH1a because these enzymes stand out from the others regarding their activity. From the structural and kinetic analysis, we can state that five residues at positions 163, 288, 289, 444, and 454 (PsAMADHs numbering) can, directly or not, significantly modulate AMADH substrate specificity. In the SlAMADH1 structure, a PEG aldehyde derived from the precipitant forms a thiohemiacetal intermediate, never observed so far. Its absence in the SlAMADH1-E260A structure suggests that Glu-260 can activate the catalytic cysteine as a nucleophile. We show that the five AMADHs studied here are capable of oxidizing 3-dimethylsulfoniopropionaldehyde to the cryo- and osmoprotectant 3-dimethylsulfoniopropionate. For the first time, we also show that 3-acetamidopropionaldehyde, the third aminoaldehyde besides 3-aminopropionaldehyde and 4-aminobutyraldehyde, is generally oxidized by AMADHs, meaning that these enzymes are unique in metabolizing and detoxifying aldehyde products of polyamine degradation to nontoxic amino acids. Finally, gene expression profiles in maize indicate that AMADHs might be important for controlling ω-aminoaldehyde levels during early stages of the seed development.
- MeSH
- Aldehyde Oxidoreductases chemistry genetics metabolism MeSH
- Aldehydes chemistry MeSH
- Models, Chemical MeSH
- Phylogeny MeSH
- Plant Physiological Phenomena MeSH
- Kinetics MeSH
- Crystallography, X-Ray methods MeSH
- Zea mays enzymology MeSH
- Mutagenesis, Site-Directed MeSH
- NAD chemistry MeSH
- Polyethylene Glycols chemistry MeSH
- Gene Expression Regulation, Enzymologic * MeSH
- Gene Expression Regulation, Plant * MeSH
- Plants enzymology MeSH
- Seeds metabolism MeSH
- Solanum lycopersicum enzymology MeSH
- Substrate Specificity MeSH
- Protein Binding MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Aldehyde dehydrogenases (ALDHs) are responsible for oxidation of biogenic aldehyde intermediates as well as for cell detoxification of aldehydes generated during lipid peroxidation. So far, 13 ALDH families have been described in plants. In the present study, we provide a detailed biochemical characterization of plant ALDH2 and ALDH7 families by analysing maize and pea ALDH7 (ZmALDH7 and PsALDH7) and four maize cytosolic ALDH(cALDH)2 isoforms RF2C, RF2D, RF2E and RF2F [the first maize ALDH2 was discovered as a fertility restorer (RF2A)]. We report the crystal structures of ZmALDH7, RF2C and RF2F at high resolution. The ZmALDH7 structure shows that the three conserved residues Glu(120), Arg(300) and Thr(302) in the ALDH7 family are located in the substrate-binding site and are specific to this family. Our kinetic analysis demonstrates that α-aminoadipic semialdehyde, a lysine catabolism intermediate, is the preferred substrate for plant ALDH7. In contrast, aromatic aldehydes including benzaldehyde, anisaldehyde, cinnamaldehyde, coniferaldehyde and sinapaldehyde are the best substrates for cALDH2. In line with these results, the crystal structures of RF2C and RF2F reveal that their substrate-binding sites are similar and are formed by an aromatic cluster mainly composed of phenylalanine residues and several nonpolar residues. Gene expression studies indicate that the RF2C gene, which is strongly expressed in all organs, appears essential, suggesting that the crucial role of the enzyme would certainly be linked to the cell wall formation using aldehydes from phenylpropanoid pathway as substrates. Finally, plant ALDH7 may significantly contribute to osmoprotection because it oxidizes several aminoaldehydes leading to products known as osmolytes.
- MeSH
- Aldehyde Dehydrogenase chemistry genetics metabolism MeSH
- Phylogeny MeSH
- Pisum sativum enzymology genetics MeSH
- Isoenzymes chemistry genetics metabolism MeSH
- Catalytic Domain genetics MeSH
- Kinetics MeSH
- Crystallography, X-Ray MeSH
- Zea mays enzymology genetics MeSH
- Models, Genetic MeSH
- Models, Molecular MeSH
- Molecular Sequence Data MeSH
- NAD metabolism MeSH
- Plant Proteins chemistry genetics metabolism MeSH
- Plants enzymology genetics MeSH
- Amino Acid Sequence MeSH
- Gene Expression Profiling MeSH
- Substrate Specificity MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Prolin má jako jediná aminokyselina primární dusík uvnitř pyrrolidinového kruhu a z toho vyplývají jeho jedinečné vlastnosti. Jeho biosyntéza v organismech probíhá několika drahami. Substrátem může být glutamát a arginin, popř. ornitin, zatímco v degradaci prolinu se organismy mezi sebou neliší. Prolin je velmi důležitou aminokyselinou a jeho funkce se u živočichů a rostlin zásadně liší. V případě lidského organismu je prolin zásadní složkou kolagenu a nově byla popsána jeho účast v metabolismu nádorových buněk. U rostlin plní prolin především úlohu osmoprotektantu, molekuly, která pomáhá rostlinám překonat stres vyvolaný nedostatkem vody. Prolin má však v obou říších eukaryot mnoho dalších funkcí.
Proline is the only amino acid which has primary nitrogen inside of pyrrolidine ring and because of that proline has unique properties. There are several different pathways of proline synthesis in eukaryotic organisms. Glutamate and arginine, respectively ornithine are possible substrates for proline synthesis, while degradation is not different among eukaryotic organisms. Proline is an important amino acid and its functions are fundamentally different in animals and plants. In the case of the human, proline is essential component of collagen and its participation in the metabolism of cancer cells was newly described. In plants, proline functions mainly as osmoprotectant and helps to overcome water stress. However, proline has many other functions.
- MeSH
- Antioxidants MeSH
- Atherosclerosis metabolism MeSH
- Hydroxyproline MeSH
- Collagen * MeSH
- Humans MeSH
- Neoplasms metabolism MeSH
- Proline * biosynthesis chemistry metabolism MeSH
- Plants MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Plant response to water deficit and subsequent re-watering is fine tuned at the whole plant level. It differs not only between shoot and root, but also among particular leaves along a plant axis. We estimated the expression of proline metabolism-related genes and the activity of senescence-related promoter in roots and individual leaves of tobacco plants in the course of drought stress and recovery. Proline plays the dual role of an osmoprotectant and an antioxidant under water deficit. High proline concentration in the youngest uppermost leaves contributed to their protection from drought, which was associated with low degree of senescence. During recovery, elevated proline concentrations persisted and the senescence-related promoter was switched off in all surviving leaves. Two mutually exclusive scenarios were followed by tobacco leaves on recovery--restoration of photosynthesis and metabolism, or death, depending on the progress of senescence.
- MeSH
- Stress, Physiological MeSH
- Droughts MeSH
- Nicotiana physiology MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Plants in natural environments are increasingly being subjected to a combination of abiotic stresses, such as drought and warming, in many regions. The effects of each stress and the combination of stresses on the functioning of shoots and roots have been studied extensively, but little is known about the simultaneous metabolome responses of the different organs of the plant to different stresses acting at once. We studied the shift in metabolism and elemental composition of shoots and roots of two perennial grasses, Holcus lanatus and Alopecurus pratensis, in response to simultaneous drought and warming. These species responded differently to individual and simultaneous stresses. These responses were even opposite in roots and shoots. In plants exposed to simultaneous drought and warming, terpenes, catechin and indole acetic acid accumulated in shoots, whereas amino acids, quinic acid, nitrogenous bases, the osmoprotectants choline and glycine betaine, and elements involved in growth (nitrogen, phosphorus and potassium) accumulated in roots. Under drought, warming further increased the allocation of primary metabolic activity to roots and changed the composition of secondary metabolites in shoots. These results highlight the plasticity of plant metabolomes and stoichiometry, and the different complementary responses of shoots and roots to complex environmental conditions.
- MeSH
- Principal Component Analysis MeSH
- Discriminant Analysis MeSH
- Species Specificity MeSH
- Holcus metabolism MeSH
- Plant Roots metabolism MeSH
- Poaceae metabolism MeSH
- Metabolome MeSH
- Metabolomics * MeSH
- Least-Squares Analysis MeSH
- Droughts * MeSH
- Elements MeSH
- Seasons MeSH
- Plant Shoots metabolism MeSH
- Hot Temperature * MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of vitamin-A and plant hormones that regulate plant growth and response to adverse growth conditions, has been mainly focusing on provitamin A biofortification or the production of high-value carotenoids. Here, we show that the introduction of a single gene of the carotenoid biosynthetic pathway in different tomato cultivars induced profound metabolic alterations in carotenoid, apocarotenoid and phytohormones pathways. Alterations in isoprenoid- (abscisic acid, gibberellins, cytokinins) and non-isoprenoid (auxin and jasmonic acid) derived hormones together with enhanced xanthophyll content influenced biomass partitioning and abiotic stress tolerance (high light, salt, and drought), and it caused an up to 77% fruit yield increase and enhanced fruit's provitamin A content. In addition, metabolic and hormonal changes led to accumulation of key primary metabolites (e.g. osmoprotectants and antiaging agents) contributing with enhanced abiotic stress tolerance and fruit shelf life. Our findings pave the way for developing a new generation of crops that combine high productivity and increased nutritional value with the capability to cope with climate change-related environmental challenges.
Plant NAD(+)-dependent aminoaldehyde dehydrogenases (AMADHs, EC 1.2.1.19) belong to the family 10 of aldehyde dehydrogenases. They participate in the metabolism of polyamines or osmoprotectants. The enzymes are characterized by their broad substrate specificity covering ω-aminoaldehydes, aliphatic and aromatic aldehydes as well as nitrogen-containing heterocyclic aldehydes. The isoenzyme 1 from tomato (Solanum lycopersicum; SlAMADH1) oxidizes aliphatic aldehydes very efficiently and converts also furfural, its derivatives or benzaldehyde, which are present at low concentrations in alcoholic distillates such as fruit brandy. In this work, SlAMADH1 was examined as a bioanalytical tool for their detection. These aldehydes arise from fermentation processes or thermal degradation of sugars and their presence is related to health complications after consumption including nausea, emesis, sweating, decrease in blood pressure, hangover headache, among others. Sixteen samples of slivovitz (plum brandy) from local producers in Moravia, Czech Republic, were analyzed for their aldehyde content using a spectrophotometric activity assay with SlAMADH1. In all cases, there were oxidative responses observed when monitoring NADH production in the enzymatic reaction. Aldehydes in the distillate samples were also subjected to a standard determination using reversed-phase HPLC with spectrophotometric and tandem mass spectrometric detection after a derivatization with 2,4-dinitrophenylhydrazine. Results obtained by both methods were found to correlate well for a majority of the analyzed samples. The possible applicability of SlAMADH1 for the evaluation of aldehyde content in food and beverages has now been demonstrated.
- MeSH
- Aldehydes adverse effects analysis MeSH
- Alcoholic Beverages adverse effects analysis MeSH
- Biotechnology MeSH
- Distillation MeSH
- Isoenzymes metabolism MeSH
- Kinetics MeSH
- Humans MeSH
- Fruit chemistry MeSH
- Retinal Dehydrogenase metabolism MeSH
- Plant Proteins metabolism MeSH
- Prunus domestica chemistry MeSH
- Solanum lycopersicum enzymology MeSH
- Tandem Mass Spectrometry MeSH
- Chromatography, High Pressure Liquid MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Plant aminoaldehyde dehydrogenases (AMADHs, EC 1.2.1.19) belong to the family 10 of aldehyde dehydrogenases and participate in the metabolism of compounds related to amino acids such as polyamines or osmoprotectants. Their broad specificity covers ω-aminoaldehydes, aliphatic and aromatic aldehydes as well as nitrogen-containing heterocyclic aldehydes. The substrate preference of plant AMADHs is determined by the presence of aspartic acid and aromatic residues in the substrate channel. In this work, 15 new N-acyl derivates of 3-aminopropanal (APAL) and 4-aminobutanal (ABAL) were synthesized and confirmed as substrates of two pea AMADH isoenzymes (PsAMADH 1 and 2). The compounds were designed considering the previously demonstrated conversion of N-acetyl derivatives as well as substrate channel dimensions (5-8 Å × 14 Å). The acyl chain length and its branching were found less significant for substrate properties than the length of the initial natural substrate. In general, APAL derivatives were found more efficient than the corresponding ABAL derivatives because of the prevailing higher conversion rates and lower K m values. Differences in enzymatic performance between the two isoenzymes corresponded in part to their preferences to APAL to ABAL. The higher PsAMADH2 affinity to substrates correlated with more frequent occurrence of an excess substrate inhibition. Molecular docking indicated the possible auxiliary role of Tyr163, Ser295 and Gln451 in binding of the new substrates. The only derivative carrying a free carboxyl group (N-adipoyl APAL) was surprisingly better substrate than ABAL in PsAMADH2 reaction indicating that also negatively charged aldehydes might be good substrates for ALDH10 family.
- MeSH
- Aldehyde Dehydrogenase chemistry metabolism MeSH
- Aldehydes chemistry metabolism MeSH
- Pisum sativum chemistry enzymology MeSH
- Kinetics MeSH
- Molecular Structure MeSH
- Propylamines chemistry metabolism MeSH
- Plant Proteins chemistry metabolism MeSH
- Molecular Docking Simulation MeSH
- Substrate Specificity MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Plant cytosolic aldehyde dehydrogenases from family 2 (ALDH2s, EC 1.2.1.3) are non-specific enzymes and participate for example in the metabolism of acetaldehyde or biosynthesis of phenylpropanoids. Plant aminoaldehyde dehydrogenases (AMADHs, ALDH10 family, EC 1.2.1.19) are broadly specific and play an important role in polyamine degradation or production of osmoprotectants. We have tested imidazole and pyrazole carbaldehydes and their alkyl-, allyl-, benzyl-, phenyl-, pyrimidinyl- or thienyl-derivatives as possible substrates of plant ALDH2 and ALDH10 enzymes. Imidazole represents a building block of histidine, histamine as well as certain alkaloids. It also appears in synthetic pharmaceuticals such as imidazole antifungals. Biological compounds containing pyrazole are rare (e.g. pyrazole-1-alanine and pyrazofurin antibiotics) but the ring is often found as a constituent of many synthetic drugs and pesticides. The aim was to evaluate whether aldehyde compounds based on azole heterocycles are oxidized by the enzymes, which would further support their expected role as detoxifying aldehyde scavengers. The analyzed imidazole and pyrazole carbaldehydes were only slowly converted by ALDH10s but well oxidized by cytosolic maize ALDH2 isoforms (particularly by ALDH2C1). In the latter case, the respective Km values were in the range of 10-2000 μmol l-1; the kcat values appeared mostly between 0.1 and 1.0 s-1. The carbaldehyde group at the position 4 of imidazole was oxidized faster than that at the position 2. Such a difference was not observed for pyrazole carbaldehydes. Aldehydes with an aromatic substituent on their heterocyclic ring were oxidized faster than those with an aliphatic substituent. The most efficient of the tested substrates were comparable to benzaldehyde and p-anisaldehyde known as the best aromatic aldehyde substrates of plant cytosolic ALDH2s in vitro.
- MeSH
- Aldehyde Dehydrogenase metabolism MeSH
- Aldehydes chemistry metabolism MeSH
- Pisum sativum enzymology MeSH
- Imidazoles chemistry metabolism MeSH
- Zea mays enzymology MeSH
- Molecular Structure MeSH
- Oxidation-Reduction MeSH
- Pyrazoles chemistry metabolism MeSH
- Solanum lycopersicum enzymology MeSH
- Publication type
- Journal Article MeSH
A comparative analysis of various parameters that characterize plant morphology, growth, water status, photosynthesis, cell damage, and antioxidative and osmoprotective systems together with an iTRAQ analysis of the leaf proteome was performed in two inbred lines of maize (Zea mays L.) differing in drought susceptibility and their reciprocal F1 hybrids. The aim of this study was to dissect the parent-hybrid relationships to better understand the mechanisms of the heterotic effect and its potential association with the stress response. The results clearly showed that the four examined genotypes have completely different strategies for coping with limited water availability and that the inherent properties of the F1 hybrids, i.e. positive heterosis in morphological parameters (or, more generally, a larger plant body) becomes a distinct disadvantage when the water supply is limited. However, although a greater loss of photosynthetic efficiency was an inherent disadvantage, the precise causes and consequences of the original predisposition towards faster growth and biomass accumulation differed even between reciprocal hybrids. Both maternal and paternal parents could be imitated by their progeny in some aspects of the drought response (e.g., the absence of general protein down-regulation, changes in the levels of some carbon fixation or other photosynthetic proteins). Nevertheless, other features (e.g., dehydrin or light-harvesting protein contents, reduced chloroplast proteosynthesis) were quite unique to a particular hybrid. Our study also confirmed that the strategy for leaving stomata open even when the water supply is limited (coupled to a smaller body size and some other physiological properties), observed in one of our inbred lines, is associated with drought-resistance not only during mild drought (as we showed previously) but also during more severe drought conditions.
- MeSH
- Acclimatization MeSH
- Chimera genetics physiology MeSH
- Photosynthesis MeSH
- Stress, Physiological MeSH
- Hybrid Vigor * MeSH
- Zea mays anatomy & histology genetics physiology MeSH
- Plant Leaves anatomy & histology genetics physiology MeSH
- Droughts MeSH
- Proteome analysis metabolism MeSH
- Plant Proteins analysis metabolism MeSH
- Water metabolism MeSH
- Publication type
- Journal Article MeSH
