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

• Published in: PLoS genetics Vol. 10; no. 12; p. e1004791
• Main Authors: Yang, Li, Zhang, Jing, He, Junna, Qin, Yingying, Hua, Deping, Duan, Ying, Chen, Zhizhong, Gong, Zhizhong
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.12.2014; Public Library of Science (PLoS)
• Subjects: Abscisic acid; Abscisic Acid - pharmacology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biology and Life Sciences; Botanical research; Cloning; Electron Transport Complex I - genetics; Electron Transport Complex I - metabolism; Ethanol; Gene expression; Genetic aspects; Genetic research; Genotype; Glycerol; Growth hormones; Health aspects; Homeostasis; Introns; Meristem - genetics; Meristem - metabolism; Mitochondria; Mitochondria - metabolism; Phenotype; Plant Development; Plant growth; Plant Roots - genetics; Plant Roots - metabolism; Promoter Regions, Genetic; Proteins; Reactive oxygen species; Reactive Oxygen Species - metabolism; RNA Splicing; Signal Transduction; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1004791

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.