scholarly journals Dioxygenase-encoding AtDAO1 gene controls IAA oxidation and homeostasis in Arabidopsis

2016 ◽  
Vol 113 (39) ◽  
pp. 11016-11021 ◽  
Author(s):  
Silvana Porco ◽  
Aleš Pěnčík ◽  
Afaf Rashed ◽  
Ute Voß ◽  
Rubén Casanova-Sáez ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Molecular Basis ◽  
Growth And Development ◽  
Iaa Oxidase ◽  
Gain Of Function ◽  
Steady State Levels ◽  
Mutant Lines ◽  
Acting In Concert ◽  
Indole 3 Acetic Acid ◽  
Iaa Conjugates

Auxin represents a key signal in plants, regulating almost every aspect of their growth and development. Major breakthroughs have been made dissecting the molecular basis of auxin transport, perception, and response. In contrast, how plants control the metabolism and homeostasis of the major form of auxin in plants, indole-3-acetic acid (IAA), remains unclear. In this paper, we initially describe the function of the Arabidopsis thaliana gene DIOXYGENASE FOR AUXIN OXIDATION 1 (AtDAO1). Transcriptional and translational reporter lines revealed that AtDAO1 encodes a highly root-expressed, cytoplasmically localized IAA oxidase. Stable isotope-labeled IAA feeding studies of loss and gain of function AtDAO1 lines showed that this oxidase represents the major regulator of auxin degradation to 2-oxoindole-3-acetic acid (oxIAA) in Arabidopsis. Surprisingly, AtDAO1 loss and gain of function lines exhibited relatively subtle auxin-related phenotypes, such as altered root hair length. Metabolite profiling of mutant lines revealed that disrupting AtDAO1 regulation resulted in major changes in steady-state levels of oxIAA and IAA conjugates but not IAA. Hence, IAA conjugation and catabolism seem to regulate auxin levels in Arabidopsis in a highly redundant manner. We observed that transcripts of AtDOA1 IAA oxidase and GH3 IAA-conjugating enzymes are auxin-inducible, providing a molecular basis for their observed functional redundancy. We conclude that the AtDAO1 gene plays a key role regulating auxin homeostasis in Arabidopsis, acting in concert with GH3 genes, to maintain auxin concentration at optimal levels for plant growth and development.

Isoperoxidases of (IAA oxidase) oxidase in oat coleoptiles

1973 ◽  
Vol 51 (11) ◽  
pp. 2047-2052 ◽  
Author(s):  
William R. Gordon ◽  
James H. M. Henderson
Keyword(s):  
Acetic Acid ◽  
Avena Sativa ◽  
Gel Electrophoresis ◽  
Enzyme Assay ◽  
Polyacrylamide Gel Electrophoresis ◽  
Acid Oxidase ◽  
Iaa Oxidase ◽  
Substrate Specificities ◽  
Electrophoretic Mobilities ◽  
Indole 3 Acetic Acid

Eight constitutive isoperoxidases were separated by the disc method of polyacrylamide gel electrophoresis from a lyophilized extract of 8-day-old oat (Avena sativa L., cv. Victory) coleoptiles. Both anodic and cathodic isoperoxidases were studied and differences in electrophoretic mobilities and hydrogen donor substrate specificities were revealed. In addition, by enzyme assay, cathodic and anodic isoenzymes were shown to possess differences in peroxidase and IAA (indole-3-acetic acid) oxidase activities.Treatment of coleoptiles with 0.07 mM IAA for 24 h resulted in the repression of two slow-migrating anodic isoperoxidases; however, the same treatment also resulted in the induction of two slow-migrating cathodic isoenzymes which were shown to exhibit peroxidase and IAA oxidase activities.

scholarly journals Chlorinated Auxins—How Does Arabidopsis Thaliana Deal with Them?

2020 ◽  
Vol 21 (7) ◽  
pp. 2567 ◽  
Author(s):  
Antje Walter ◽  
Lorenzo Caputi ◽  
Sarah O’Connor ◽  
Karl-Heinz van Pée ◽  
Jutta Ludwig-Müller
Keyword(s):  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Model Organism ◽  
Wild Type ◽  
In Planta ◽  
Bacteria And Fungi ◽  
Tryptophan Derivatives ◽  
Indole 3 Acetic Acid ◽  
Iaa Conjugates

Plant hormones have various functions in plants and play crucial roles in all developmental and differentiation stages. Auxins constitute one of the most important groups with the major representative indole-3-acetic acid (IAA). A halogenated derivate of IAA, 4-chloro-indole-3-acetic acid (4-Cl-IAA), has previously been identified in Pisum sativum and other legumes. While the enzymes responsible for the halogenation of compounds in bacteria and fungi are well studied, the metabolic pathways leading to the production of 4-Cl-IAA in plants, especially the halogenating reaction, are still unknown. Therefore, bacterial flavin-dependent tryptophan-halogenase genes were transformed into the model organism Arabidopsis thaliana. The type of chlorinated indole derivatives that could be expected was determined by incubating wild type A. thaliana with different Cl-tryptophan derivatives. We showed that, in addition to chlorinated IAA, chlorinated IAA conjugates were synthesized. Concomitantly, we found that an auxin conjugate synthetase (GH3.3 protein) from A. thaliana was able to convert chlorinated IAAs to amino acid conjugates in vitro. In addition, we showed that the production of halogenated tryptophan (Trp), indole-3-acetonitrile (IAN) and IAA is possible in transgenic A. thaliana in planta with the help of the bacterial halogenating enzymes. Furthermore, it was investigated if there is an effect (i) of exogenously applied Cl-IAA and Cl-Trp and (ii) of endogenously chlorinated substances on the growth phenotype of the plants.

Content and Metabolism of Indole-3-acetic Acid (IAA) in Healthy and Rust-Infected Wheat Leaf Segments

1986 ◽  
Vol 41 (11-12) ◽  
pp. 1023-1031
Author(s):  
Gertrud Wiese ◽  
Hans J. Grambow
Keyword(s):  
Acetic Acid ◽  
Stem Rust ◽  
Main Part ◽  
Rust Fungus ◽  
Rapid Exchange ◽  
Germination Medium ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Indole 3 Acetic Acid ◽  
Iaa Conjugates

Abstract The content of IAA in stem rust-infected susceptible wheat leaves shows a highly pronounced maximum 5-6 days after inoculation, shortly prior to the onset of sporulation. This auxin increase can not only be caused by a reduced degradation of IAA. Considerable amounts of IAA are also found in urediospores and germlings; the IAA is in part released by them into the germination medium. IAA applied exogenously to wheat leaves is channelled into two different degradation path­ways: (a) into the peroxidase-catalysed decarboxylation which leads to indole-3-methanol and subsequent products as well as into (b) a non-decarboxylative path which leads to a number of oxindolic compounds. Furthermore, IAA conjugates such as IAAglc and IAAsp are formed. The formation of the products is characteristically dependent upon the concentration of the IAA applied. In rust fungus-infected wheat leaves, all IAA metabolites occur which are known in healthy leaves. The mode of their formation after “feeding” of radioactively-labelled IAA leads to the conclusion that the main part of the IAA in the infected leaves is present in a pool which does not permit a rapid exchange with the IAA taken up. The results lead to the hypothesis that IAA is present, to a major extent, in the structures of the fungus and is probably also produced by it.

The peanut gynophore: a developmental and physiological perspective

2003 ◽  
Vol 81 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Edgar Moctezuma
Keyword(s):  
Acetic Acid ◽  
Arachis Hypogaea ◽  
Growth Rates ◽  
Growth And Development ◽  
Plant Hormone ◽  
Physiological Changes ◽  
Light Touch ◽  
Peanut Plant ◽  
Arachis Hypogaea L ◽  
Indole 3 Acetic Acid

The peanut plant (Arachis hypogaea L.) produces flowers aerially, but it is able to "sow" its own seeds as a result of the growth of a specialized organ called the gynophore. The peanut gynophore is sensitive to light, touch, and gravity, and it is capable of transporting the recently fertilized ovules into the soil. For gynophore growth to occur, many physiological changes in plant hormone accumulation and distribution take place throughout its development. The unique characteristics and physiological events occurring during the gynophore's growth and development, such as its growth rates and indole-3-acetic acid redistribution during gravistimulation, will be reviewed. The peanut gynophore illustrates that the study of the odd or unusual can often provide valuable answers about the typical.Key words: Arachis hypogaea, geocarpy, gravitropism, gynophore, indole-3-acetic acid (IAA), peanut.

scholarly journals Redefining the roles of UDP-glycosyltransferases in auxin metabolism and homeostasis during plant development

2021 ◽  
Author(s):  
Eduardo Mateo-Bonmatí ◽  
Rubén Casanova-Sáez ◽  
Jan Šimura ◽  
Karin Ljung
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Plant Development ◽  
Plant Growth Regulator ◽  
Growth And Development ◽  
Plant Tissues ◽  
Plant Growth And Development ◽  
Concentration Gradients ◽  
Indole 3 Acetic Acid ◽  
Reversible Nature

ABSTRACTThe levels of the important plant growth regulator indole-3-acetic acid (IAA) are tightly controlled within plant tissues to spatiotemporally orchestrate concentration gradients that drive plant growth and development. Metabolic inactivation of bioactive IAA is known to participate in the modulation of IAA maxima and minima. IAA can be irreversibly inactivated by oxidation and conjugation to Aspartate and Glutamate. Usually overlooked because its reversible nature, the most abundant inactive IAA form is the IAA-glucose (IAA-glc) conjugate. Glycosylation of IAA is reported to be carried out by the UDP-glycosyltransferase 84B1 (UGT84B1), while UGT74D1 has been implicated in the glycosylation of the irreversibly formed IAA catabolite oxIAA. Here we demonstrate that both UGT84B1 and UGT74D1 modulate IAA levels throughout plant development by dual IAA and oxIAA glycosylation. Moreover, we identify a novel UGT subfamily whose members modulate IAA homeostasis during skotomorphogenesis by redundantly mediating the glycosylation of oxIAA.

scholarly journals Dynamic regulation of auxin oxidase and conjugating enzymes AtDAO1 and GH3 modulates auxin homeostasis

2016 ◽  
Vol 113 (39) ◽  
pp. 11022-11027 ◽  
Author(s):  
Nathan Mellor ◽  
Leah R. Band ◽  
Aleš Pěnčík ◽  
Ondřej Novák ◽  
Afaf Rashed ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Extended Model ◽  
Plant Growth And Development ◽  
Dynamic Regulation ◽  
Auxin Homeostasis ◽  
High Auxin ◽  
Root Tissues ◽  
Indole 3 Acetic Acid

The hormone auxin is a key regulator of plant growth and development, and great progress has been made understanding auxin transport and signaling. Here, we show that auxin metabolism and homeostasis are also regulated in a complex manner. The principal auxin degradation pathways in Arabidopsis include oxidation by Arabidopsis thaliana gene DIOXYGENASE FOR AUXIN OXIDATION 1/2 (AtDAO1/2) and conjugation by Gretchen Hagen3s (GH3s). Metabolic profiling of dao1-1 root tissues revealed a 50% decrease in the oxidation product 2-oxoindole-3-acetic acid (oxIAA) and increases in the conjugated forms indole-3-acetic acid aspartic acid (IAA-Asp) and indole-3-acetic acid glutamic acid (IAA-Glu) of 438- and 240-fold, respectively, whereas auxin remains close to the WT. By fitting parameter values to a mathematical model of these metabolic pathways, we show that, in addition to reduced oxidation, both auxin biosynthesis and conjugation are increased in dao1-1. Transcripts of AtDAO1 and GH3 genes increase in response to auxin over different timescales and concentration ranges. Including this regulation of AtDAO1 and GH3 in an extended model reveals that auxin oxidation is more important for auxin homoeostasis at lower hormone concentrations, whereas auxin conjugation is most significant at high auxin levels. Finally, embedding our homeostasis model in a multicellular simulation to assess the spatial effect of the dao1-1 mutant shows that auxin increases in outer root tissues in agreement with the dao1-1 mutant root hair phenotype. We conclude that auxin homeostasis is dependent on AtDAO1, acting in concert with GH3, to maintain auxin at optimal levels for plant growth and development.

scholarly journals Constructing Auxin-Inducible Degron Mutants Using an All-in-One Vector

2020 ◽  
Vol 13 (5) ◽  
pp. 103 ◽  
Author(s):  
Aisha Yesbolatova ◽  
Yuichiro Saito ◽  
Masato T. Kanemaki
Keyword(s):  
Acetic Acid ◽  
Protein Function ◽  
Mammalian Cells ◽  
Gene Knockout ◽  
Mutant Line ◽  
Drug Selection ◽  
Replication Factor ◽  
Protein Components ◽  
Mutant Lines ◽  
Indole 3 Acetic Acid

Conditional degron-based methods are powerful for studying protein function because a degron-fused protein can be rapidly and efficiently depleted by adding a defined ligand. Auxin-inducible degron (AID) is a popular technology by which a degron-fused protein can be degraded by adding an auxin. However, compared with other technologies such as dTAG and HaloPROTAC, AID is complicated because of its two protein components: OsTIR1 and mAID (degron). To simplify the use of AID in mammalian cells, we constructed bicistronic all-in-one plasmids that express OsTIR1 and a mAID-fused protein using a P2A self-cleavage sequence. To generate a HeLa mutant line for the essential replication factor MCM10, we transfected a CRISPR-knockout plasmid together with a bicistronic plasmid containing mAID-fused MCM10 cDNA. After drug selection and colony isolation, we successfully isolated HeLa mutant lines, in which mAID–MCM10 was depleted by the addition of indole-3-acetic acid, a natural auxin. The bicistronic all-in-one plasmids described in this report are useful for controlling degradation of a transgene-derived protein fused with mAID. These plasmids can be used for the construction of conditional mutants by combining them with a CRISPR-based gene knockout.

scholarly journals STRAIN ENTEROBACTER SP. UOM-3 IS ABLE TO SYNCHRONOUS DESTRUCTION OF HALOGEN-CONTAINING HERBICIDES AND SYNTHESIS OF INDOL-3-ACETIC ACID

ÈKOBIOTEH ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 716-721
Author(s):  
S.N. Starikov ◽  
◽  
S.P. Chetverikov ◽  
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Maximum Concentration ◽  
Culture Medium ◽  
Plant Growth And Development ◽  
Biological Product ◽  
Stimulate Plant Growth ◽  
Indole 3 Acetic Acid

We studied the Enterobacter sp. UOM-3 oil destructor strain that was isolated and identified earlier. During the study, it was shown that these bacteria are able to synthesize indole-3-acetic acid (IAA) when growing in culture medium with the halogen-containing herbicides Octapon and Florax: the destruction of 2,4-D on the 4th day of cultivation reached 79% and 68%, respectively, the maximum concentration of IAA during the experiment was 485 ng / ml and 270 ng / ml. The strain can be applied as part of a biological product to remediate the environment and to stimulate plant growth and development.

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