title: Plastid-localized glutathione reductase2-regulated glutathione redox status is essential for Arabidopsis root apical meristem maintenance.
abstract: Glutathione is involved in thiol redox signaling and acts as a major redox buffer against reactive oxygen species, helping to maintain a reducing environment in vivo. Glutathione reductase (GR) catalyzes the reduction of glutathione disulfide (GSSG) into reduced glutathione (GSH). The Arabidopsis thaliana genome encodes two GRs: GR1 and GR2. Whereas the cytosolic/peroxisomal GR1 is not crucial for plant development, we show here that the plastid-localized GR2 is essential for root growth and root apical meristem (RAM) maintenance. We identify a GR2 mutant, miao, that displays strong inhibition of root growth and severe defects in the RAM, with GR activity being reduced to ∼50%. miao accumulates high levels of GSSG and exhibits increased glutathione oxidation. The exogenous application of GSH or the thiol-reducing agent DTT can rescue the root phenotype of miao, demonstrating that the RAM defects in miao are triggered by glutathione oxidation. Our in silico analysis of public microarray data shows that auxin and glutathione redox signaling generally act independently at the transcriptional level. We propose that glutathione redox status is essential for RAM maintenance through both auxin/PLETHORA (PLT)-dependent and auxin/PLT-independent redox signaling pathways.
authors.affiliation: Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, D-79104 Freiburg, Germany.
authors.forename: Xin
authors.initials: X
authors.lastname: Yu
authors.forename: Taras
authors.initials: T
authors.lastname: Pasternak
authors.forename: Monika
authors.initials: M
authors.lastname: Eiblmeier
authors.forename: Franck
authors.initials: F
authors.lastname: Ditengou
authors.forename: Philip
authors.initials: P
authors.lastname: Kochersperger
authors.forename: Jiaqiang
authors.initials: J
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Heinz
authors.initials: H
authors.lastname: Rennenberg
authors.forename: William
authors.initials: W
authors.lastname: Teale
authors.forename: Ivan
authors.initials: I
authors.lastname: Paponov
authors.forename: Wenkun
authors.initials: W
authors.lastname: Zhou
authors.forename: Chuanyou
authors.initials: C
authors.lastname: Li
authors.forename: Xugang
authors.initials: X
authors.lastname: Li
authors.forename: Klaus
authors.initials: K
authors.lastname: Palme
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005978:Glutathione / Q000378:metabolism*; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000494:pharmacology; D018519:Meristem / Q000378:metabolism*; D009154:Mutation; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism*; D030821:Plants, Genetically Modified; D018087:Plastids / Q000201:enzymology*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D005980:Glutathione Reductase; D005978:Glutathione