scholarly journals Chemical inhibition of auxin inactivation pathway uncovers the metabolic turnover of auxin homeostasis

2021 ◽  
Author(s):  
Kosuke Fukui ◽  
Kazushi Arai ◽  
Yuka Tanaka ◽  
Yuki Aoi ◽  
Vandna Kukshal ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Amino Acid ◽  
Plant Development ◽  
In Planta ◽  
Auxin Homeostasis ◽  
Auxin Concentration ◽  
Auxin Synthesis ◽  
Chemical Inhibition ◽  
Conjugating Enzymes ◽  
Indole 3 Acetic Acid

The phytohormone auxin, specifically indole-3-acetic acid (IAA) plays a prominent role in plant development. Cellular auxin concentration is coordinately regulated by auxin synthesis, transport, and inactivation to maintain auxin homeostasis; however, the physiological contribution of auxin inactivation to auxin homeostasis has remained elusive. The GH3 genes encode auxin amino acid conjugating enzymes that perform a central role in auxin inactivation. The chemical inhibition of GH3s in planta is challenging because the inhibition of GH3 enzymes leads to IAA overaccumulation that rapidly induces GH3 expression. Here, we developed a potent GH3 inhibitor, designated as kakeimide (KKI), that selectively targets auxin-conjugating GH3s. Chemical knockdown of the auxin inactivation pathway demonstrates that auxin turnover is very rapid (about 10 min), indicating auxin biosynthesis and inactivation dynamically regulate auxin homeostasis.

scholarly journals The main oxidative inactivation pathway of the plant hormone auxin

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ken-ichiro Hayashi ◽  
Kazushi Arai ◽  
Yuki Aoi ◽  
Yuka Tanaka ◽  
Hayao Hira ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Amino Acid ◽  
Plant Development ◽  
Plant Hormone ◽  
Amino Acid Conjugates ◽  
Auxin Homeostasis ◽  
Oxidative Inactivation ◽  
Indole 3 Acetic Acid

AbstractInactivation of the phytohormone auxin plays important roles in plant development, and several enzymes have been implicated in auxin inactivation. In this study, we show that the predominant natural auxin, indole-3-acetic acid (IAA), is mainly inactivated via the GH3-ILR1-DAO pathway. IAA is first converted to IAA-amino acid conjugates by GH3 IAA-amidosynthetases. The IAA-amino acid conjugates IAA-aspartate (IAA-Asp) and IAA-glutamate (IAA-Glu) are storage forms of IAA and can be converted back to IAA by ILR1/ILL amidohydrolases. We further show that DAO1 dioxygenase irreversibly oxidizes IAA-Asp and IAA-Glu into 2-oxindole-3-acetic acid-aspartate (oxIAA-Asp) and oxIAA-Glu, which are subsequently hydrolyzed by ILR1 to release inactive oxIAA. This work established a complete pathway for the oxidative inactivation of auxin and defines the roles played by auxin homeostasis in plant development.

Synthesis of amino acid derivatives of indole-3-acetic acid

2005 ◽  
Vol 2005 (10) ◽  
pp. 640-642 ◽  
Author(s):  
Ying Liu ◽  
Liang Zhao ◽  
Liang Liu ◽  
Lin-Yi Wei ◽  
Lu-Hua Lai
Keyword(s):  
Acetic Acid ◽  
Amino Acid ◽  
Amino Acid Derivatives ◽  
H Nmr ◽  
Derivatives Of ◽  
Indole 3 Acetic Acid

Amino acid derivatives of a modified indole-3-acetic acid have been synthesised. Fourteen new dipeptide-like compounds 3–4 were obtained and their structures were elucidated based on the IR, 1H NMR, MS spectra.

Effects of humic substances and indole-3-acetic acid on Arabidopsis sugar and amino acid metabolic profile

2018 ◽  
Vol 426 (1-2) ◽  
pp. 17-32 ◽  
Author(s):  
Giovanni Battista Conselvan ◽  
David Fuentes ◽  
Andrew Merchant ◽  
Cristina Peggion ◽  
Ornella Francioso ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Amino Acid ◽  
Humic Substances ◽  
Metabolic Profile ◽  
Indole 3 Acetic Acid

Indole-3-Acetic Acid Protein Conjugates: Novel Players in Auxin Homeostasis

Plant Biology ◽  
2006 ◽  
Vol 8 (3) ◽  
pp. 340-345 ◽  
Author(s):  
C. Seidel ◽  
A. Walz ◽  
S. Park ◽  
J. D. Cohen ◽  
J. Ludwig-Müller
Keyword(s):  
Acetic Acid ◽  
Auxin Homeostasis ◽  
Protein Conjugates ◽  
Acid Protein ◽  
Indole 3 Acetic Acid

Binding behavior of amino acid conjugates of indole-3-acetic acid to immobilized human serum albumin

2007 ◽  
Vol 1154 (1-2) ◽  
pp. 240-249 ◽  
Author(s):  
Ana Tomašić ◽  
Branimir Bertoša ◽  
Sanja Tomić ◽  
Milan Šoškić ◽  
Volker Magnus
Keyword(s):  
Acetic Acid ◽  
Amino Acid ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Amino Acid Conjugates ◽  
Binding Behavior ◽  
Indole 3 Acetic Acid

The Route, Control and Compartmentation of Auxin Synthesis

1993 ◽  
Vol 20 (5) ◽  
pp. 527 ◽  
Author(s):  
HM Nonhebel ◽  
TP Cooney ◽  
R Simpson
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Recent Work ◽  
Aspartate Aminotransferase ◽  
Acid Synthesis ◽  
Pea Seedlings ◽  
Auxin Synthesis ◽  
Aromatic Aminotransferase ◽  
Work Supports ◽  
Indole 3 Acetic Acid

The study of indole-3-acetic acid synthesis has undergone something of a revival recently in an attempt to understand the control of IAA levels. Results are, however, contradictory with three separate hypotheses emerging. Our own work supports older evidence for L-tryptophan as the IAA precursor and appears to simplify the metabolism of tryptophan to IAA. Work comparing incorporation of 2H from 2H2O into IAA, tryptophan, tryptamine and indole-3-pyruvate in tomato shoots showed that the indole-3-pyruvate became labelled at a rate compatible with it being the sole intermediate between tryptophan and indole-3-acetaldehyde. Results also showed that tryptamine was not involved in IAA synthesis although it was present. Indole-3-acetaldoxime was not detected in tomato shoots. An aromatic aminotransferase able to catalyse the synthesis of indole-3-pyruvate has been purified from mung beans. This enzyme was separated from aspartate aminotransferase and is fairly specific for aromatic L-amino acids. Other work, however, has implicated D-tryptophan as a more direct precursor than the L-enantiomer. A D-tryptophan aminotransferase has been isolated from dark grown pea seedlings. Finally, other recent work has indicated the existence of an alternative biosynthetic route to IAA which does not involve tryptophan. These results are reviewed in this paper and the apparent contradictions between them discussed.

scholarly journals In Planta Production of Indole-3-Acetic Acid by Colletotrichum gloeosporioides f. sp. aeschynomene

2004 ◽  
Vol 70 (3) ◽  
pp. 1852-1854 ◽  
Author(s):  
Rudy Maor ◽  
Sefi Haskin ◽  
Hagit Levi-Kedmi ◽  
Amir Sharon
Keyword(s):  
Acetic Acid ◽  
Fungal Biomass ◽  
Colletotrichum Gloeosporioides ◽  
Pathogenic Fungus ◽  
Plant Colonization ◽  
In Planta ◽  
Iaa Production ◽  
Axenic Cultures ◽  
Indole 3 Acetic Acid ◽  
Iaa Biosynthesis

ABSTRACT The plant pathogenic fungus Colletotrichum gloeosporioides f. sp. aeschynomene utilizes external tryptophan to produce indole-3-acetic acid (IAA) through the intermediate indole-3-acetamide (IAM). We studied the effects of tryptophan, IAA, and IAM on IAA biosynthesis in fungal axenic cultures and on in planta IAA production by the fungus. IAA biosynthesis was strictly dependent on external tryptophan and was enhanced by tryptophan and IAM. The fungus produced IAM and IAA in planta during the biotrophic and necrotrophic phases of infection. The amounts of IAA produced per fungal biomass were highest during the biotrophic phase. IAA production by this plant pathogen might be important during early stages of plant colonization.

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