Rice acclimation to soil flooding: Low concentrations of organic acids can trigger a barrier to radial oxygen loss in roots

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DOI

  • Timothy David Colmer, University of Western Australia
  • ,
  • Lukasz Kotula, University of Western Australia
  • ,
  • Al Imran Malik, University of Western Australia
  • ,
  • Hirokazu Takahashi, Nagoya University
  • ,
  • Dennis Konnerup
  • Mikio Nakazono, University of Western Australia, Nagoya University
  • ,
  • Ole Pedersen, University of Western Australia, Freshwater Biological Laboratory, University of Copenhagen

Waterlogged soils contain monocarboxylic acids produced by anaerobic microorganisms. These “organic acids” can accumulate to phytotoxic levels and promote development of a barrier to radial O2 loss (ROL) in roots of some wetland species. Environmental cues triggering root ROL barrier induction, a feature that together with tissue gas-filled porosity facilitates internal aeration, are important to elucidate for knowledge of plant stress physiology. We tested the hypothesis that comparatively low, non-toxic, concentrations of acetic, propionic, butyric, and/or hexanoic acids might induce root ROL barrier formation in rice. Each organic acid, individually, triggered the ROL barrier in roots but with no effect (acetic or butyric acids) or with only slight effects (propionic or hexanoic acids) on root extension. Transcripts of four genes related to suberin biosynthesis were increased by some of the organic acid treatments. Respiration in root tissues was not, or moderately, inhibited. Beyond a narrow concentration range, however, respiration declined exponentially and the order (least to greatest) for EC50 (effective concentration for 50% inhibition) was butyric, propionic, acetic, then hexanoic acid. An understanding of the environmental cue for root ROL barrier induction should enhance future work to elucidate the molecular regulation of this root trait contributing to plant flooding tolerance.

Original languageEnglish
JournalPlant Cell and Environment
Volume42
Issue7
Pages (from-to)2183-2197
Number of pages15
ISSN0140-7791
DOIs
Publication statusPublished - Jul 2019

    Research areas

  • aerenchyma, lignin, Oryza sativa, ROL, root internal aeration, root respiration, soil phytotoxins, soil waterlogging, suberin, transcripts

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