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Thioredoxin h2 contributes to the redox regulation of mitochondrial photorespiratory metabolism
Author(s) -
FonsecaPereira Paula,
Souza Paulo V.L.,
Hou LiangYu,
Schwab Saskia,
Geigenberger Peter,
NunesNesi Adriano,
Timm Stefan,
Fernie Alisdair R.,
Thormählen Ina,
Araújo Wagner L.,
Daloso Danilo M.
Publication year - 2020
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13640
Subject(s) - photorespiration , thioredoxin , biochemistry , serine hydroxymethyltransferase , biology , metabolism , mitochondrion , cellular respiration , redox , photosynthesis , nad+ kinase , serine , microbiology and biotechnology , chemistry , enzyme , organic chemistry
Abstract Thioredoxins (TRXs) are important proteins involved in redox regulation of metabolism. In plants, it has been shown that the mitochondrial metabolism is regulated by the mitochondrial TRX system. However, the functional significance of TRX h2 , which is found at both cytosol and mitochondria, remains unclear. Arabidopsis plants lacking TRX h2 showed delayed seed germination and reduced respiration alongside impaired stomatal and mesophyll conductance, without impacting photosynthesis under ambient O 2 conditions. However, an increase in the stoichiometry of photorespiratory CO 2 release was found during O 2 ‐dependent gas exchange measurements in trxh2 mutants. Metabolite profiling of trxh2 leaves revealed alterations in key metabolites of photorespiration and in several metabolites involved in respiration and amino acid metabolism. Decreased abundance of serine hydroxymethyltransferase and glycine decarboxylase (GDC) H and L subunits as well as reduced NADH/NAD + ratios were also observed in trxh2 mutants. We further demonstrated that the redox status of GDC‐L is altered in trxh2 mutants in vivo and that recombinant TRX h2 can deactivate GDC‐L in vitro, indicating that this protein is redox regulated by the TRX system. Collectively, our results demonstrate that TRX h 2 plays an important role in the redox regulation of mitochondrial photorespiratory metabolism.