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Plant Sci. 2018 May;270:278-291. doi: 10.1016/j.plantsci.2018.02.023. Epub 2018 Mar 3.

SELENOPROTEIN O is a chloroplast protein involved in ROS scavenging and its absence increases dehydration tolerance in Arabidopsis thaliana.

Author information

1
School of Plant Sciences and Food Security, Tel Aviv University, P.O. Box 39040, Tel Aviv 6997801, Israel.
2
Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany.
3
The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
4
Institute of Plant Biology, Biological Research Center of Hungarian Academy of Sciences, Temesvári krt. 62/64, H-6724 Szeged, Hungary.
5
Protein Mass Spectrometry Group, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany.
6
Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany; Institute of Plant Biology, Biological Research Center of Hungarian Academy of Sciences, Temesvári krt. 62/64, H-6724 Szeged, Hungary.
7
School of Plant Sciences and Food Security, Tel Aviv University, P.O. Box 39040, Tel Aviv 6997801, Israel. Electronic address: aviah@post.tau.ac.il.

Abstract

The evolutionary conserved family of Selenoproteins performs redox-regulatory functions in bacteria, archaea and eukaryotes. Among them, members of the SELENOPROTEIN O (SELO) subfamily are located in mammalian and yeast mitochondria, but their functions are thus far enigmatic. Screening of T-DNA knockout mutants for resistance to the proline analogue thioproline (T4C), identified mutant alleles of the plant SELO homologue in Arabidopsis thaliana. Absence of SELO resulted in a stress-induced transcriptional activation instead of silencing of mitochondrial proline dehydrogenase, and also high elevation of Δ(1)-pyrroline-5-carboxylate dehydrogenase involved in degradation of proline, thereby alleviating T4C inhibition and lessening drought-induced proline accumulation. Unlike its animal homologues, SELO was localized to chloroplasts of plants ectopically expressing SELO-GFP. The protein was co-fractionated with thylakoid membrane complexes, and co-immunoprecipitated with FNR, PGRL1 and STN7, all involved in regulating PSI and downstream electron flow. The selo mutants displayed extended survival under dehydration, accompanied by longer photosynthetic activity, compared with wild-type plants. Enhanced expression of genes encoding ROS scavenging enzymes in the unstressed selo mutant correlated with higher oxidant scavenging capacity and reduced methyl viologen damage. The study elucidates SELO as a PSI-related component involved in regulating ROS levels and stress responses.

KEYWORDS:

Abiotic stress signaling; Drought tolerance; Proline metabolism; ROS; Selenoprotein O

PMID:
29576081
DOI:
10.1016/j.plantsci.2018.02.023
[Indexed for MEDLINE]

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