Three oxidative metabolites of indole-3-acetic acid from Arabidopsis thaliana

Regulation of Auxin Homeostasis and Gradients in Arabidopsis Roots through the Formation of the Indole-3-Acetic Acid Catabolite 2-Oxindole-3-Acetic Acid

“…These compounds can then be further metabolized to oxIAAGlc, oxIAA-Asp, and hydroxy(OH)-IAA-Asp (Östin et al, 1998;Kai et al, 2007). Additional IAA metabolites have been identified in Arabidopsis, such as IAA-Glc, IAA-Val, IAA-Phe, 6-OH-IAA-Val, and 6-OH-IAA-Phe (Kai et al, 2007), IAA-Trp (Staswick 2009), and IAA-Ala and IAA-Leu (Kowalczyk and Sandberg, 2001;Rampey et al, 2004).…”

“…It is known that auxin can be conjugated to amino acids and sugars to either storage forms or to irreversible degradation products, and several genes involved in IAA conjugation and deconjugation have been identified (reviewed in Ludwig-Müller, 2011;Korasick et al, 2013). Data from our laboratory and others have demonstrated that oxidation of IAA to 2-oxindole-3-acetic acid (oxIAA) is another important pathway for IAA degradation in plant species such as Arabidopsis (Östin et al, 1998;Kowalczyk and Sandberg 2001;Kai et al, 2007;Novák et al, 2012;Peer et al, 2013), maize (Zea mays; Reinecke and Bandurski, 1983), and Pinus sylvestris (Ernstsen et al, 1987). These findings have mainly been based on the use of radioactive and labeled precursor feeding and/or mass spectrometry identification and quantification of the main IAA degradation products.…”

“…These findings have mainly been based on the use of radioactive and labeled precursor feeding and/or mass spectrometry identification and quantification of the main IAA degradation products. To our knowledge, no genes and/or enzymes have so far been identified in IAA catabolic/oxidation Oxidation of IAA to oxIAA, and subsequent conjugation with Glc to form oxIAA-Glc, is a major route for IAA catabolism in Arabidopsis, based on feeding experiments with labeled precursors and mass spectrometry-based quantification of IAA metabolites (Östin et al, 1998;Kowalczyk and Sandberg, 2001;Kai et al, 2007;Kubeš et al, 2012;Peer et al, 2013). IAA can also be conjugated to either Glc or amino acids (AA), and these compounds can be further metabolized to oxIAA-Glc, 6-OH-IAA-AA, and oxIAA-AA.…”

“…Some of these conjugates may act as reversible storage forms of IAA that can later be hydrolyzed to produce free IAA. The most abundant AA conjugates in Arabidopsis seedlings are normally IAA-Asp and IAA-Glu (Östin et al, 1998;Tam et al, 2000;Kowalczyk and Sandberg, 2001;Kai et al, 2007;Novák et al, 2012). pathways in plants, making it difficult to study the specific regulation and function of IAA catabolism in planta.…”

Conversion of Endogenous Indole-3-Butyric Acid to Indole-3-Acetic Acid Drives Cell Expansion in Arabidopsis Seedlings

“…Mutation of Arabidopsis (Arabidopsis thaliana) genes encoding IAA-amino acid hydrolases, including ILR1, IAR3, and ILL2, reduces plant sensitivity to the applied IAA-amino acid conjugates that are substrates of these enzymes, including IAA-Leu, IAA-Phe, and IAA-Ala (Bartel and Fink, 1995;Davies et al, 1999;LeClere et al, 2002;Rampey et al, 2004), which are present in Arabidopsis (Tam et al, 2000;Kowalczyk and Sandberg, 2001;Kai et al, 2007).…”