Tissue-specific profiling of the Arabidopsis thaliana auxin metabolome

Authors

  • Ondřej Novák,

    1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
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    • These authors contributed equally to this work.

  • Eva Hényková,

    1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
    2. Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Šlechtitelů 11, 78371 Olomouc, Czech Republic
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    • These authors contributed equally to this work.

  • Ilkka Sairanen,

    1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
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  • Mariusz Kowalczyk,

    1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
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    • Present address: Department of Biochemistry, Institute of Soil Science and Plant Cultivation, PL-24100 Pulawy, Poland.

  • Tomáš Pospíšil,

    1. Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, 78371 Olomouc, Czech Republic
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  • Karin Ljung

    Corresponding author
    1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
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(e-mail karin.ljung@slu.se).

Summary

The plant hormone auxin is believed to influence almost every aspect of plant growth and development. Auxin transport, biosynthesis and degradation combine to form gradients of the hormone that influence a range of key developmental and environmental response processes. There is abundant genetic evidence for the existence of multiple pathways for auxin biosynthesis and degradation. The complexity of these pathways makes it difficult to obtain a clear picture of the relative importance of specific metabolic pathways during development. We have developed a sensitive mass spectrometry-based method to simultaneously profile the majority of known auxin precursors and conjugates/catabolites in small amounts of Arabidopsis tissue. The method includes a new derivatization technique for quantification of the most labile of the auxin precursors. We validated the method by profiling the auxin metabolome in root and shoot tissues from various Arabidopsis thaliana ecotypes and auxin over-producing mutant lines. Substantial differences were shown in metabolite patterns between the lines and tissues. We also found differences of several orders of magnitude in the abundance of auxin metabolites, potentially indicating the relative importance of these compounds in the maintenance of auxin levels and activity. The method that we have established will enable researchers to obtain a better understanding of the dynamics of auxin metabolism and activity during plant growth and development.

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