Facile Preparation of Deuterium-Labeled Standards of Indole-3-Acetic Acid (IAA) and Its Metabolites to Quantitatively Analyze the Disposition of Exogenous IAA in<i>Arabidopsis thaliana</i>

Kai, Kenji; Nakamura, Shunsuke; Wakasa, K.; Miyagawa, Hisashi

doi:10.1271/bbb.70151

Cited by 14 publications

(9 citation statements)

References 28 publications

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“…The incubation of cells with radiolabelled NAA, 2,4-D or the non-auxin weak acid BeA revealed metabolic changes that were fastest for BeA and NAA. Glucosyl ester conjugates represented the major form of respective metabolites as shown for NAA in this work and also by Kai et al (2007) for IAA. Such glucosyl ester conjugates or other auxin metabolites were not detected in the cultivation media and therefore did not seem to be substrates for the auxin efflux transporters.…”

Section: Discussionsupporting

confidence: 69%

Auxin transport at cellular level: new insights supported by mathematical modelling

Hošek

Kubeš

Laňková

et al. 2012

Journal of Experimental Botany

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The molecular basis of cellular auxin transport is still not fully understood. Although a number of carriers have been identified and proved to be involved in auxin transport, their regulation and possible activity of as yet unknown transporters remain unclear. Nevertheless, using single-cell-based systems it is possible to track the course of auxin accumulation inside cells and to specify and quantify some auxin transport parameters. The synthetic auxins 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene-1-acetic acid (NAA) are generally considered to be suitable tools for auxin transport studies because they are transported specifically via either auxin influx or efflux carriers, respectively. Our results indicate that NAA can be metabolized rapidly in tobacco BY-2 cells. The predominant metabolite has been identified as NAA glucosyl ester and it is shown that all NAA metabolites were retained inside the cells. This implies that the transport efficiency of auxin efflux transporters is higher than previously assumed. By contrast, the metabolism of 2,4-D remained fairly weak. Moreover, using data on the accumulation of 2,4-D measured in the presence of auxin transport inhibitors, it is shown that 2,4-D is also transported by efflux carriers. These results suggest that 2,4-D is a promising tool for determining both auxin influx and efflux activities. Based on the accumulation data, a mathematical model of 2,4-D transport at a single-cell level is proposed. Optimization of the model provides estimates of crucial transport parameters and, together with its validation by successfully predicting the course of 2,4-D accumulation, it confirms the consistency of the present concept of cellular auxin transport.

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Section: Discussionsupporting

confidence: 69%

Auxin transport at cellular level: new insights supported by mathematical modelling

Hošek

Kubeš

Laňková

et al. 2012

Journal of Experimental Botany

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“…Two new IAA conjugates, IAA-Phe and IAA-Val, were identified indirectly, which are good substrates for the GH3 family of amidosynthases. OxIAA-Glc is proposed to be a primary oxidative metabolite of IAA in Arabidopsis based on quantification with deuterium-labeled internal standard (Kai et al 2007a;Kai et al 2007b). This recent observation is consistent with previous work in which OxIAA-hexose was identified as a major metabolite of IAA in Arabidopsis (Ostin et al 1998).…”

Section: The Identification Of New Iaa Metabolites In Arabidopsissupporting

confidence: 89%

Approaching Cellular and Molecular Resolution of Auxin Biosynthesis and Metabolism

Normanly¹

2009

Cold Spring Harbor Perspectives in Biology

199

182

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“…It was previously found that feeding Arabidopsis seedlings with IAA led to increased accumulation of IAA-Asp, IAA-Glu, IAA-GE, OxIAA and OxIAA-GE (Kai et al , 2007 b ), most likely due to the activation of multiple metabolic pathways in response to the exogenous IAA supply. Consistently with these results, our findings in selected algal species ( Scenedesmus obliquus , Chloroccocum elbense , Stigeoclonium helveticum and Microthamnion kuetzingianum ) revealed a gradual metabolization of exogenously applied [ 3 H]IAA to IAA-Asp and IAA-GE as two major products.…”

Section: Discussionmentioning

confidence: 99%

Control of cytokinin and auxin homeostasis in cyanobacteria and algae

Žižková

Kubeš

Dobrev

et al. 2016

Ann Bot

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Background and Aims The metabolism of cytokinins (CKs) and auxins in vascular plants is relatively well understood, but data concerning their metabolic pathways in non-vascular plants are still rather rare. With the aim of filling this gap, 20 representatives of taxonomically major lineages of cyanobacteria and algae from Cyanophyceae, Xanthophyceae, Eustigmatophyceae, Porphyridiophyceae, Chlorophyceae, Ulvophyceae, Trebouxiophyceae, Zygnematophyceae and Klebsormidiophyceae were analysed for endogenous profiles of CKs and auxins and some of them were used for studies of the metabolic fate of exogenously applied radiolabelled CK, [3H]trans-zeatin (transZ) and auxin ([3H]indole-3-acetic acid (IAA)), and the dynamics of endogenous CK and auxin pools during algal growth and cell division.Methods Quantification of phytohormone levels was performed by high-performance or ultrahigh-performance liquid chromatography–electrospray tandem mass spectrometry (HPLC-MS/MS, UHPLC-MS/MS). The dynamics of exogenously applied [3H]transZ and [3H]IAA in cell cultures were monitored by HPLC with on-line radioactivity detection.Key Results The comprehensive screen of selected cyanobacteria and algae for endogenous CKs revealed a predominance of bioactive and phosphate CK forms while O- and N-glucosides evidently did not contribute greatly to the total CK pool. The abundance of cis-zeatin-type CKs and occurrence of CK 2-methylthio derivatives pointed to the tRNA pathway as a substantial source of CKs. The importance of the tRNA biosynthetic pathway was proved by the detection of tRNA-bound CKs during the course of Scenedesmus obliquus growth. Among auxins, free IAA and its oxidation catabolite 2-oxindole-3-acetic acid represented the prevailing endogenous forms. After treatment with [3H]IAA, IAA-aspartate and indole-3-acetyl-1-glucosyl ester were detected as major auxin metabolites. Moreover, different dynamics of endogenous CKs and auxin profiles during S. obliquus culture clearly demonstrated diverse roles of both phytohormones in algal growth and cell division.Conclusions Our data suggest the existence and functioning of a complex network of metabolic pathways and activity control of CKs and auxins in cyanobacteria and algae that apparently differ from those in vascular plants.

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Facile Preparation of Deuterium-Labeled Standards of Indole-3-Acetic Acid (IAA) and Its Metabolites to Quantitatively Analyze the Disposition of Exogenous IAA inArabidopsis thaliana

Cited by 14 publications

References 28 publications

Auxin transport at cellular level: new insights supported by mathematical modelling

Auxin transport at cellular level: new insights supported by mathematical modelling

Approaching Cellular and Molecular Resolution of Auxin Biosynthesis and Metabolism

Control of cytokinin and auxin homeostasis in cyanobacteria and algae

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