Journal of Plant Physiology 176 (2015) 192–201 Contents lists available at ScienceDirect Journal of Plant Physiology journa l h om epage: www.elsevier.com/locate/jplph Review article Plant glutathione peroxidases: Emerging role of the antioxidant enzymes in plant development and stress responses Krisztina Bela a , Edit Horváth a , Ágnes Gallé a , László Szabados b , Irma Tari a , Jolán Csiszár a,∗ a Department of Plant Biology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52., H-6726 Szeged, Hungary b Institute of Plant Biology, Biological Research Centre of HAS, Temesvári krt. 62., H-6726 Szeged, Hungary a r t i c l e i n f o Article history: Received 6 October 2014 Received in revised form 15 December 2014 Accepted 15 December 2014 Available online 13 January 2015 Keywords: Antioxidant enzyme Plant glutathione peroxidase Reactive oxygen species Redox regulation a b s t r a c t The plant glutathione peroxidase (GPX) family consists of multiple isoenzymes with distinct subcellular locations which exhibit different tissue-specific expression patterns and environmental stress responses. Contrary to most of their counterparts in animal cells, plant GPXs contain cysteine instead of selenocys- teine in their active site and while some of them have both glutathione peroxidase and thioredoxin peroxidase functions, the thioredoxin regenerating system is much more efficient in vitro than the glu- tathione system. At present, the function of these enzymes in plants is not completely understood. The occurrence of thiol-dependent activities of plant GPX isoenzymes suggests that – besides detoxification of H 2 O 2 and organic hydroperoxides – they may be involved in regulation of the cellular redox homeo- stasis by maintaining the thiol/disulfide or NADPH/NADP + balance. GPXs may represent a link existing between the glutathione- and the thioredoxin-based system. The various thiol buffers, including Trx, can affect a number of redox reactions in the cells most probably via modulation of thiol status. It is still required to identify the in vivo reductant for particular GPX isoenzymes and partners that GPXs interact with specifically. Recent evidence suggests that plant GPXs does not only protect cells from stress induced oxidative damage but they can be implicated in plant growth and development. Following a more gen- eral introduction, this study summarizes present knowledge on plant GPXs, highlighting the results on gene expression analysis, regulation and signaling of Arabidopsis thaliana GPXs and also suggests some perspectives for future research. © 2015 Elsevier GmbH. All rights reserved. Contents The plant glutathione peroxidases are members of the thioredoxin-dependent peroxidase family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 The mammalian glutathione peroxidases (GPxs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 The plant glutathione peroxidases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 The role of plant GPXs in stress responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 The plant GPXs and the oxidative stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 GPXs and the redox regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 Arabidopsis thaliana glutathione peroxidases—Lessons from a model plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 AtGPX1 and AtGPX7—The chloroplastic isoenzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 AtGPX2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 AtGPX3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Abbreviations: ABA, abscisic acid; ABI, abscisic acid insensitive; APX, ascorbate peroxidase; AS, antisense; ASC, ascorbate; CAT, catalase; DHA, dehydroascorbic acid; GA, gibberellic acid; GPX, glutathione peroxidase; GPx4/PHGPX, phospholipid hydroperoxide glutathione peroxidase/animal GPx4 enzime; GR, glutathione reductase; GRX, glutaredoxin; GSH, reduced glutathione; GSSG, oxidized glutathione/glutathione disulfide; GST, glutathione transferase; IAA, indole-3-acetic acid; MeJA, methyl jasmonate; POD, guaiacol peroxidase; Prx, peroxiredoxin/thioredoxin peroxidase; ROS, reactive oxygen species; SOD, superoxide dismutase; SA, salicylic acid; Trx, thioredoxin. ∗ Corresponding author. Tel.: +36 62 544 307; fax: +36 62 544 307. E-mail address: csiszar@bio.u-szeged.hu (J. Csiszár). http://dx.doi.org/10.1016/j.jplph.2014.12.014 0176-1617/© 2015 Elsevier GmbH. All rights reserved.