Ancient Plant Glyoxylate/Succinic Semialdehyde Reductases: GLYR1s Are Cytosolic, Whereas GLYR2s Are Localized to Both Mitochondria and Plastids.

Carolyne J Brikis,Barry J Shelp,Christopher P Trobacher,Adel Zarei,Gale G Bozzo,Robert T Mullen,Kazuhito Akama,Jennifer R Deell

doi:10.3389/fpls.2017.00601

Abstract

Plant NADPH-dependent glyoxylate/succinic semialdehyde reductases 1 and 2 (GLYR1 and GLYR2) are considered to be involved in detoxifying harmful aldehydes, thereby preserving plant health during exposure to various abiotic stresses. Phylogenetic analysis revealed that the two GLYR isoforms appeared in the plant lineage prior to the divergence of the Chlorophyta and Streptophyta, which occurred approximately 750 million years ago. Green fluorescent protein fusions of apple (Malus x domestica Borkh.), rice (Oryza sativa L.) and Arabidopsis thaliana [L.] Heynh GLYRs were transiently expressed in tobacco (Nicotiana tabaccum L.) suspension cells or Arabidopsis protoplasts, as well in methoxyfenozide-induced, stably transformed Arabidopsis seedlings. The localization of apple GLYR1 confirmed that this isoform is cytosolic, whereas apple, rice and Arabidopsis GLYR2s were localized to both mitochondria and plastids. These findings highlight the potential involvement of GLYRs within distinct compartments of the plant cell.

Highlights

Plant NADPH-dependent glyoxylate/succinic semialdehyde (SSA) reductases (GLYR, EC 1.2.1.79) are hypothesized to detoxify harmful reactive aldehydes into their corresponding less toxic alcohols, thereby preserving plant health during various abiotic stresses (Allan et al, 2009)
AtGLYR1 has been shown to be localized to cytosol, whereas AtGLYR2 is localized to plastids (Simpson et al, 2008; Ching et al, 2012)
We studied evolutionary relationships between the two plant GLYRs and compared the subcellular localization of GLYRs from apple (Malus × domestica Borkh.), a dicotyledonous species, and rice (Oryza sativa L.), a monocotyledonous species, with those from Arabidopsis thaliana [L] Heynh

Summary

Introduction

Plant NADPH-dependent glyoxylate/succinic semialdehyde (SSA) reductases (GLYR, EC 1.2.1.79) are hypothesized to detoxify harmful reactive aldehydes into their corresponding less toxic alcohols, thereby preserving plant health during various abiotic stresses (Allan et al, 2009). In silico analysis of subcellular localization using TargetP (Emanuelsson et al, 2000) and WoLF PSORT (Horton et al, 2007) revealed that these cucurbit GLYR2As, like their Arabidopsis, apple and rice counterparts (Supplementary Figure S1A), possess a putative N-terminal mitochondrial/chloroplastidial targeting sequence, whereas the cucurbit GLYR2Bs do not.

Results

Conclusion