Image_7_AtDAT1 Is a Key Enzyme of D-Amino Acid Stimulated Ethylene Production in Arabidopsis thaliana.tif
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, the Arabidopsis accession Landsberg erecta (Ler) got into focus as it was found defective in metabolizing D-AAs. Combining genetics and molecular biology of T-DNA insertion lines and natural variants together with biochemical and physiological approaches, we could identify AtDAT1 as a major D-AA transaminase in Arabidopsis. Atdat1 loss-of-function mutants and Arabidopsis accessions with defective AtDAT1 alleles were unable to produce the metabolites of D-Met, D-Ala, D-Glu, and L-Met. This result corroborates the biochemical characterization, which showed highest activity of AtDAT1 using D-Met as a substrate. Germination of seedlings in light and dark led to enhanced growth inhibition of atdat1 mutants on D-Met. Ethylene measurements revealed an increased 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 a reciprocal relation of malonylated methionine and ACC upon D-Met application and significantly more malonyl-methionine in atdat1 mutants. Unexpectedly, the malonyl-ACC levels did not differ between mutants and wild type. With AtDAT1, the first central enzyme of plant D-AA metabolism was characterized biochemically and physiologically. The specific effects of D-Met on ACC metabolism, ethylene production, and plant development of dat1 mutants unraveled the impact of AtDAT1 on these processes; however, they are not in full accordance to previous working models. Instead, our results imply the influence of additional factors or processes on D-AA-stimulated ethylene production, which await to be uncovered.
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References
- https://doi.org//10.2134/agronj1970.00021962006200020002x
- https://doi.org//10.1016/S0038-0717(00)00195-4
- https://doi.org//10.1016/j.geoderma.2005.01.017
- https://doi.org//10.1016/j.coph.2014.12.004
- https://doi.org//10.1111/j.1365-313X.2004.02231.x
- https://doi.org//10.1111/j.1399-3054.1995.tb00977.x
- https://doi.org//10.1007/s00726-002-0322-8
- https://doi.org//10.1007/s10533-005-5733-7
- https://doi.org//10.1021/bi0000162
- https://doi.org//10.1007/s00018-010-0571-8
- https://doi.org//10.1006/abbi.2000.2138
- https://doi.org//10.1104/pp.17.01272
- https://doi.org//10.1104/pp.113.1.119
- https://doi.org//10.1046/j.1365-313x.1998.00343.x
- https://doi.org//10.1104/pp.103.027979
- https://doi.org//10.1016/j.brainresrev.2006.08.005
- https://doi.org//10.1146/annurev-micro-091213-112844
- https://doi.org//10.1093/nar/19.6.1349
- https://doi.org//10.1038/nbt946
- https://doi.org//10.1007/s11103-004-7902-9
- https://doi.org//10.1104/pp.97.1.19
- https://doi.org//10.12703/P6-37
- https://doi.org//10.1111/j.1469-8137.2008.02546.x
- https://doi.org//10.1016/j.ymgme.2005.03.003
- https://doi.org//10.1016/j.jchromb.2011.05.051
- https://doi.org//10.1023/A:1016031014871
- https://doi.org//10.1111/j.1742-4658.2008.06279.x
- https://doi.org//10.1007/s00726-010-0674-4
- https://doi.org//10.1186/2193-1801-2-559
- https://doi.org//10.1016/S0031-9422(97)00965-5
- https://doi.org//10.1111/j.1365-313X.2010.04322.x
- https://doi.org//10.1016/S1570-0232(02)00690-6
- https://doi.org//10.1248/cpb.55.503
- https://doi.org//10.1146/annurev-arplant-042110-103819
- https://doi.org//10.1371/journal.pone.0019220
- https://doi.org//10.1038/1841296b0
- https://doi.org//10.1038/1841296b0
- https://doi.org//10.3389/fpls.2019.00695
- https://doi.org//10.1016/j.jchromb.2011.03.062
- https://doi.org//10.1007/BF00397444
- https://doi.org//10.1126/science.1188628
- https://doi.org//10.1126/science.1178123
- https://doi.org//10.1111/plb.12405
- https://doi.org//10.1371/journal.pgen.0010006
- https://doi.org//10.1016/S0031-9422(00)81090-0
- https://doi.org//10.1007/BF00397737
- https://doi.org//10.1104/pp.77.4.891
- https://doi.org//10.1042/BJ20130896
- https://doi.org//10.1002/cbdv.200900245
- https://doi.org//10.1126/science.1201101
- https://doi.org//10.1111/plb.12198
- https://doi.org//10.3389/fmicb.2016.02001
- https://doi.org//10.3389/fpls.2018.00114
- https://doi.org//10.1111/j.1365-313X.2007.03212.x
- https://doi.org//10.1104/pp.18.00126
- https://doi.org//10.1002/psc.2637
- https://doi.org//10.1264/jsme2.ME15126
- https://doi.org//10.1007/BF00386229
- https://doi.org//10.1111/j.1399-3054.1982.tb06318.x
- https://doi.org//10.1073/pnas.1503272112
- https://doi.org//10.1021/bi061097q
- https://doi.org//10.1104/pp.40.2.335
- https://doi.org//10.3389/fpls.2014.00640
- https://doi.org//10.3389/fpls.2017.00038
- https://doi.org//10.1038/nrmicro2960
- https://doi.org//10.1007/s11104-011-1059-5
- https://doi.org//10.1371/journal.pone.0000718
- https://doi.org//10.1016/0031-9422(95)00320-7
- https://doi.org//10.1146/annurev.pp.35.060184.001103
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