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The jasmonic acid signaling pathway is linked to auxin homeostasis through the modulation of YUCCA8 and YUCCA9 gene expression

Authors

  • Mathias Hentrich,

    1. Department of Plant Physiology, Ruhr-University Bochum, Bochum, Germany
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  • Christine Böttcher,

    1. Department of Plant Physiology, Ruhr-University Bochum, Bochum, Germany
    Current affiliation:
    1. CSIRO Plant Industry, Hartley Grove, Urrbrae, Australia
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  • Petra Düchting,

    1. Department of Plant Physiology, Ruhr-University Bochum, Bochum, Germany
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  • Youfa Cheng,

    1. Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
    Current affiliation:
    1. Institute of Botany, Chinese Academy of Sciences, Xiangshan, China
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  • Yunde Zhao,

    1. Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
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  • Oliver Berkowitz,

    1. Research School of Biology, Australian National University, Canberra, Australia
    Current affiliation:
    1. School of Biological Sciences and Biotechnology, Murdoch University South St Murdoch WA 6150 and School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley, Perth, Australia
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  • Josette Masle,

    1. Research School of Biology, Australian National University, Canberra, Australia
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  • Joaquín Medina,

    1. Centro de Biotecnología y Genómica de Plantas (CBGP), Campus de Montegancedo, 28223 Pozuelo de Alarcón (Madrid), Spain
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  • Stephan Pollmann

    Corresponding author
    1. Centro de Biotecnología y Genómica de Plantas (CBGP), Campus de Montegancedo, 28223 Pozuelo de Alarcón (Madrid), Spain
    • Department of Plant Physiology, Ruhr-University Bochum, Bochum, Germany
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For correspondence (e-mail stephan.pollmann@upm.es).

Summary

Interactions between phytohormones play important roles in the regulation of plant growth and development, but knowledge of the networks controlling hormonal relationships, such as between oxylipins and auxins, is just emerging. Here, we report the transcriptional regulation of two Arabidopsis YUCCA genes, YUC8 and YUC9, by oxylipins. Similar to previously characterized YUCCA family members, we show that both YUC8 and YUC9 are involved in auxin biosynthesis, as demonstrated by the increased auxin contents and auxin-dependent phenotypes displayed by gain-of-function mutants as well as the significantly decreased indole-3-acetic acid (IAA) levels in yuc8 and yuc8/9 knockout lines. Gene expression data obtained by qPCR analysis and microscopic examination of promoter-reporter lines reveal an oxylipin-mediated regulation of YUC9 expression that is dependent on the COI1 signal transduction pathway. In support of these findings, the roots of the analyzed yuc knockout mutants displayed a reduced response to methyl jasmonate (MeJA). The similar response of the yuc8 and yuc9 mutants to MeJA in cotyledons and hypocotyls suggests functional overlap of YUC8 and YUC9 in aerial tissues, while their function in roots shows some specificity, probably in part related to different spatio-temporal expression patterns of the two genes. These results provide evidence for an intimate functional relationship between oxylipin signaling and auxin homeostasis.

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