ABA-mediated ROS in Mitochondria Regulate Root Meristem Activity by Controlling PLETHORA Expression in Arabidopsis

PLoS Genet. 2014 Dec 18;10(12):e1004791. doi: 10.1371/journal.pgen.1004791. eCollection 2014 Dec.

Abstract

Although research has determined that reactive oxygen species (ROS) function as signaling molecules in plant development, the molecular mechanism by which ROS regulate plant growth is not well known. An aba overly sensitive mutant, abo8-1, which is defective in a pentatricopeptide repeat (PPR) protein responsible for the splicing of NAD4 intron 3 in mitochondrial complex I, accumulates more ROS in root tips than the wild type, and the ROS accumulation is further enhanced by ABA treatment. The ABO8 mutation reduces root meristem activity, which can be enhanced by ABA treatment and reversibly recovered by addition of certain concentrations of the reducing agent GSH. As indicated by low ProDR5:GUS expression, auxin accumulation/signaling was reduced in abo8-1. We also found that ABA inhibits the expression of PLETHORA1 (PLT1) and PLT2, and that root growth is more sensitive to ABA in the plt1 and plt2 mutants than in the wild type. The expression of PLT1 and PLT2 is significantly reduced in the abo8-1 mutant. Overexpression of PLT2 in an inducible system can largely rescue root apical meristem (RAM)-defective phenotype of abo8-1 with and without ABA treatment. These results suggest that ABA-promoted ROS in the mitochondria of root tips are important retrograde signals that regulate root meristem activity by controlling auxin accumulation/signaling and PLT expression in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / pharmacology*
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Electron Transport Complex I / genetics
  • Electron Transport Complex I / metabolism
  • Genotype
  • Introns
  • Meristem / genetics*
  • Meristem / metabolism
  • Mitochondria / metabolism*
  • Phenotype
  • Plant Development
  • Plant Roots / genetics
  • Plant Roots / metabolism
  • Promoter Regions, Genetic
  • RNA Splicing
  • Reactive Oxygen Species / metabolism*
  • Signal Transduction
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • Arabidopsis Proteins
  • PLT1 protein, Arabidopsis
  • PLT2 protein, Arabidopsis
  • Reactive Oxygen Species
  • Transcription Factors
  • Abscisic Acid
  • NAD4 protein, Arabidopsis
  • Electron Transport Complex I

Grant support

This work is supported by grants from the National Basic Research Program of China (973 Program; 2012CB114300) and the National Nature Foundation of China (91317301, 31121002). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.