Abscisic Acid Regulates Root Growth Under Osmotic Stress Conditions via an Interacting Hormonal Network With Cytokinin, Ethylene and Auxin

New Phytol. 2016 Jul;211(1):225-39. doi: 10.1111/nph.13882. Epub 2016 Feb 18.

Abstract

Understanding the mechanisms regulating root development under drought conditions is an important question for plant biology and world agriculture. We examine the effect of osmotic stress on abscisic acid (ABA), cytokinin and ethylene responses and how they mediate auxin transport, distribution and root growth through effects on PIN proteins. We integrate experimental data to construct hormonal crosstalk networks to formulate a systems view of root growth regulation by multiple hormones. Experimental analysis shows: that ABA-dependent and ABA-independent stress responses increase under osmotic stress, but cytokinin responses are only slightly reduced; inhibition of root growth under osmotic stress does not require ethylene signalling, but auxin can rescue root growth and meristem size; osmotic stress modulates auxin transporter levels and localization, reducing root auxin concentrations; PIN1 levels are reduced under stress in an ABA-dependent manner, overriding ethylene effects; and the interplay among ABA, ethylene, cytokinin and auxin is tissue-specific, as evidenced by differential responses of PIN1 and PIN2 to osmotic stress. Combining experimental analysis with network construction reveals that ABA regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin.

Keywords: Arabidopsis thaliana; PIN proteins; abscisic acid (ABA); auxin; ethylene; hormonal crosstalk, osmotic stress; root development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism*
  • Arabidopsis / genetics
  • Arabidopsis / growth & development
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Cytokinins / metabolism
  • Ethylenes / metabolism*
  • Gene Expression Regulation, Plant
  • Indoleacetic Acids / metabolism*
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Meristem / growth & development
  • Meristem / metabolism
  • Osmotic Pressure
  • Plant Roots / genetics
  • Plant Roots / growth & development*
  • Plant Roots / metabolism
  • Plants, Genetically Modified
  • Seedlings / metabolism
  • Signal Transduction

Substances

  • Arabidopsis Proteins
  • Cytokinins
  • Ethylenes
  • Indoleacetic Acids
  • Membrane Transport Proteins
  • PIN1 protein, Arabidopsis
  • PIN4 protein, Arabidopsis
  • Abscisic Acid