Mitochondrial GPX1 silencing triggers differential photosynthesis impairment in response to salinity in rice plants

The physiological role of plant mitochondrial glutathione peroxidases is scarcely known. This study attempted to elucidate the role of a rice mitochondrial isoform（GPX1） in photosynthesis under normal growth and salinity conditions. GPX1 knockdown rice lines（GPX1s） were tested in absence and presenc...

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Bibliographic Details
Published in:Journal of integrative plant biology 2016-08, Vol.58 (8), p.737-748
Main Authors: Lima‐Melo, Yugo, Carvalho, Fabricio E. L., Martins, Márcio O., Passaia, Gisele, Sousa, Rachel H. V., Neto, Milton C. Lima, Margis‐Pinheiro, Márcia, Silveira, Joaquim A. G.
Format: Article
Language:English
Subjects:
Biomass
Cell Membrane - drug effects
Cell Membrane - metabolism
Cell Membrane - radiation effects
CO2 assimilation
Gases - metabolism
Gene Silencing - drug effects
Gene Silencing - radiation effects
Glutathione - metabolism
glutathione peroxidase
Glutathione Peroxidase - metabolism
Hydrogen Peroxide - metabolism
Light
Lipid Peroxidation - drug effects
Lipid Peroxidation - radiation effects
Mitochondria - drug effects
Mitochondria - metabolism
Mitochondria - radiation effects
Oryza - drug effects
Oryza - physiology
Oryza - radiation effects
Oryza sativa
Oxidative Stress - drug effects
Oxidative Stress - radiation effects
Phenotype
photochemistry
Photosynthesis - drug effects
Photosynthesis - radiation effects
Plant Leaves - drug effects
Plant Leaves - metabolism
Plant Leaves - radiation effects
Plant Proteins - metabolism
Plant Roots - drug effects
Plant Roots - metabolism
Plant Roots - radiation effects
redox homeostasis
Salinity
Sodium Chloride - pharmacology
Stress, Physiological - drug effects
Stress, Physiological - radiation effects
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Summary:The physiological role of plant mitochondrial glutathione peroxidases is scarcely known. This study attempted to elucidate the role of a rice mitochondrial isoform（GPX1） in photosynthesis under normal growth and salinity conditions. GPX1 knockdown rice lines（GPX1s） were tested in absence and presence of 100 mM NaCl for 6 d.Growth reduction of GPX1 s line under non-stressful conditions, compared with non-transformed（NT） plants occurred in parallel to increased H_2O_2 and decreased GSH contents. These changes occurred concurrently with photosynthesis impairment, particularly in Calvin cycle＇s reactions, since photochemical efficiency did not change.Thus, GPX1 silencing and downstream molecular/metabolic changes modulated photosynthesis differentially. In contrast, salinity induced reduction in both phases of photosynthesis, which were more impaired in silenced plants.These changes were associated with root morphology alterations but not shoot growth. Both studied lines displayed increased GPX activity but H_2O_2 content did not change in response to salinity. Transformed plants exhibited lower photorespiration, water use efficiency and root growth, indicating that GPX1 could be important to salt tolerance. Growth reduction of GPX1 s line might be related to photosynthesis impairment, which in turn could have involved a cross talk mechanism between mitochondria and chloroplast originated from redox changes due to GPX1 deficiency.
ISSN:1672-9072
1744-7909
DOI:10.1111/jipb.12464