Modification of photosynthetic regulation in tomato overexpressing glutathione peroxidase.
To investigate the function of glutathione peroxidase (GPX) in plants, we produced transgenic tomato plants overexpressing an eukaryotic selenium-independent GPX (GPX5). We show here that total GPX activity was increased by 50% in transgenic plants, when compared to control plants transformed with the binary vector without the insert (PZP111). A preliminary two-dimensional electrophoretic protein analysis of the GPX overexpressing plants showed notably a decrease in the accumulation of proteins identified as rubisco small subunit 1 and fructose-1,6-bisphosphate aldolase, two proteins involved in photosynthesis. These observations, together with the fact that in standard culture conditions, GPX-overexpressing plants were not phenotypically distinct from control plants prompted us to challenge the plants with a chilling treatment that is known to affect photosynthesis activity. We found that upon chilling treatment with low light level, photosynthesis was not affected in GPX-overexpressing plants while it was in control plants, as revealed by chlorophyll fluorescence parameters and fructose-1,6-biphosphatase activity. These results suggest that overexpression of a selenium-independent GPX in tomato plants modifies specifically gene expression and leads to modifications of photosynthetic regulation processes.
Herbette
Stephane
S
UMR 547-PIAF, INRA/Université Blaise Pascal, 63177 Aubière, France.
Menn
Aline Le
AL
Rousselle
Patrick
P
Ameglio
Thierry
T
Faltin
Zehava
Z
Branlard
Gérard
G
Eshdat
Yuval
Y
Julien
Jean-Louis
JL
Drevet
Joël R
JR
Roeckel-Drevet
Patricia
P
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D003080:Cold Temperature; D015180:Electrophoresis, Gel, Two-Dimensional; D018506:Gene Expression Regulation, Plant; D005979:Glutathione Peroxidase / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics*; D051379:Mice; D010788:Photosynthesis / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000201:enzymology* / Q000235:genetics; D013735:Testicular Hormones / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
D000975:Antioxidants; D013735:Testicular Hormones; D005979:Glutathione Peroxidase; C080439:selenium-independent glutathione peroxidase