An abscisic acid-independent oxylipin pathway controls stomatal closure and immune defense in Arabidopsis

PLoS Biol. 2013;11(3):e1001513. doi: 10.1371/journal.pbio.1001513. Epub 2013 Mar 19.

Abstract

Plant stomata function in innate immunity against bacterial invasion and abscisic acid (ABA) has been suggested to regulate this process. Using genetic, biochemical, and pharmacological approaches, we demonstrate that (i) the Arabidopsis thaliana nine-specific-lipoxygenase encoding gene, LOX1, which is expressed in guard cells, is required to trigger stomatal closure in response to both bacteria and the pathogen-associated molecular pattern flagellin peptide flg22; (ii) LOX1 participates in stomatal defense; (iii) polyunsaturated fatty acids, the LOX substrates, trigger stomatal closure; (iv) the LOX products, fatty acid hydroperoxides, or reactive electrophile oxylipins induce stomatal closure; and (v) the flg22-mediated stomatal closure is conveyed by both LOX1 and the mitogen-activated protein kinases MPK3 and MPK6 and involves salicylic acid whereas the ABA-induced process depends on the protein kinases OST1, MPK9, or MPK12. Finally, we show that the oxylipin and the ABA pathways converge at the level of the anion channel SLAC1 to regulate stomatal closure. Collectively, our results demonstrate that early biotic signaling in guard cells is an ABA-independent process revealing a novel function of LOX1-dependent stomatal pathway in plant immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / pharmacology*
  • Arabidopsis / drug effects*
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Oxylipins / metabolism*
  • Plant Immunity / drug effects
  • Plant Immunity / genetics
  • Plant Stomata / drug effects*
  • Plant Stomata / genetics
  • Plant Stomata / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / genetics

Substances

  • Arabidopsis Proteins
  • Oxylipins
  • Abscisic Acid

Grant support

Grant numbers 211039 and 215477 are for SM and ST, respectively. The funder's website is www-dsv.cea.fr. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.