AtDAT1 is a key enzyme of D-amino acid stimulated ethylene production inArabidopsis thaliana
| Autor: | Sabine Hummel, Juan Pablo Suárez, Claudia Hener, Vivien-Alisa Lehnhardt, Üner Kolukisaoglu, Mark Stahl |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
D-amino acid-stimulated ethylene production Methionine Ethylene biology Mutant Wild type amino acid malonylation Plant Science 1-aminocyclopropane-1-carboxylic acid lcsh:Plant culture biology.organism_classification Amino acid D-amino acid specific transaminase D-methionine chemistry.chemical_compound Enzyme chemistry Biochemistry Arabidopsis D-amino acids in plants ethylene Arabidopsis thaliana lcsh:SB1-1110 Original Research |
| Zdroj: | Frontiers in Plant Science, Vol 10 (2019) Frontiers in Plant Science |
| DOI: | 10.1101/716373 |
| Popis: | D-enantiomers of proteinogenic amino acids (D-AAs) are found ubiquitously, but the knowledge about their metabolism and functions in plants is scarce. A long forgotten phenomenon in this regard is the D-AA-stimulated ethylene production in plants. As a starting point to investigate this effect theArabidopsisaccession Landsberg erecta (Ler) got into focus as it was found defective in metabolizing D-AAs. Combining genetics and molecular biology of T-DNA lines and natural variants together with biochemical and physiological approaches we could identify AtDAT1 as a major D-AA transaminase inArabidopsis. Atdat1loss-of-function mutants andArabidopsisaccessions with defectiveAtDAT1alleles were not able to produce D-Ala, D-Glu and L-Met, the metabolites of D-Met, anymore. This result corroborates the biochemical characterization of AtDAT1, which showed highest activity using D-Met as substrate. Germination of seedlings in light and dark led to enhanced growth inhibition ofatdat1mutants on D-Met. Ethylene measurements revealed an enhanced D-AA stimulated ethylene production in these mutants. According to initial working models of this phenomenon D-Met is preferentially malonylated instead of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). This decrease of ACC degradation should then lead to the increase of ethylene production. We could observe in our studies a reciprocal relation of malonylated methionine and ACC upon D-Met application and even significantly more malonyl-methionine inatdat1mutants. Unexpectedly, the malonyl-ACC levels did not differ between mutants and wild type in these experiments. With AtDAT1, the first central enzyme of plant D-AA metabolism was characterized biochemically and physiologically. The specific effects of D-Met on ACC metabolization, ethylene production and plant development ofdat1mutants unraveled the impact of AtDAT1 on these processes, but they are not in full accordance to previous working models. Instead, our results imply the influence of additional candidate factors or processes on D-AA-stimulated ethylene production which await to be uncovered. |
| Databáze: | OpenAIRE |
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