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Phospholipase Dε and phosphatidic acid enhance Arabidopsis nitrogen signaling and growth

Authors

  • Yueyun Hong,

    1. Department of Biology, University of Missouri, St Louis, MO 63121, USA and Donald Danforth Plant Science Center, St Louis, MO 63132, USA
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  • Shivakumar P. Devaiah,

    1. Department of Biology, University of Missouri, St Louis, MO 63121, USA and Donald Danforth Plant Science Center, St Louis, MO 63132, USA
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  • Sung Chul Bahn,

    1. Department of Biology, University of Missouri, St Louis, MO 63121, USA and Donald Danforth Plant Science Center, St Louis, MO 63132, USA
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  • Bharath N. Thamasandra,

    1. Department of Biology, University of Missouri, St Louis, MO 63121, USA and Donald Danforth Plant Science Center, St Louis, MO 63132, USA
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  • Maoyin Li,

    1. Department of Biology, University of Missouri, St Louis, MO 63121, USA and Donald Danforth Plant Science Center, St Louis, MO 63132, USA
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  • Ruth Welti,

    1. Division of Biology, Kansas State University, Manhattan, KS 66502, USA
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  • Xuemin Wang

    Corresponding author
    1. Department of Biology, University of Missouri, St Louis, MO 63121, USA and Donald Danforth Plant Science Center, St Louis, MO 63132, USA
      *For correspondence (fax +1 314 587 1519; e-mail wangxue@umsl.edu).
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*For correspondence (fax +1 314 587 1519; e-mail wangxue@umsl.edu).

Summary

Activation of phospholipase D (PLD) produces phosphatidic acid (PA), a lipid messenger implicated in cell growth and proliferation, but direct evidence for PLD and PA promotion of growth at the organism level is lacking. Here we characterize a new PLD gene, PLDε, and show that it plays a role in promoting Arabidopsis growth. PLDε is mainly associated with the plasma membrane, and is the most permissive of all PLDs tested with respect to its activity requirements. Knockout (KO) of PLDε decreases root growth and biomass accumulation, whereas over-expression (OE) of PLDε enhances root growth and biomass accumulation. The level of PA was higher in OE plants, but lower in KO plants than in wild-type plants, and suppression of PLD-mediated PA formation by alcohol alleviated the growth-promoting effect of PLDε. OE and KO of PLDε had opposite effects on lateral root elongation in response to nitrogen. Increased expression of PLDε also promoted root hair elongation and primary root growth under severe nitrogen deprivation. The results suggest that PLDε and PA promote organism growth and play a role in nitrogen signaling. The lipid-signaling process may play a role in connecting membrane sensing of nutrient status to increased plant growth and biomass production.

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