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Overexpression of rubisco activase decreases the photosynthetic CO2 assimilation rate by reducing rubisco content in rice leaves.
- Source :
-
Plant & cell physiology [Plant Cell Physiol] 2012 Jun; Vol. 53 (6), pp. 976-86. Date of Electronic Publication: 2012 Apr 01. - Publication Year :
- 2012
-
Abstract
- The effects of overexpression of Rubisco activase on photosynthesis were studied in transgenic rice expressing barley or maize Rubisco activase. Immunoblot and SDS-PAGE analyses showed that transgenic lines from both gene constructs expressed the foreign Rubisco activase at high levels. The activation state of Rubisco in transgenic lines was slightly higher than that in non-transgenic plants (NT). In addition, light activation of Rubisco was significantly more rapid in transgenic lines compared with NT. These findings indicate that the overexpression of Rubisco activase can enhance Rubisco activation. However, despite enhanced activation of Rubisco in these transgenic plants, the CO(2) assimilation rate at ambient CO(2) conditions was decreased. This decrease in CO(2) assimilation rate was observed in both young developing and mature leaves independent of nitrogen nutrition. The contents of nitrogen and Chl did not differ significantly between transformants and NT; however, Rubisco content was substantially decreased in transgenic lines. There was no evidence for reduced transcription of RbcS or RbcL in these transgenic lines; in fact, transcript levels were marginally increased compared with NT. These results indicate that the overexpression of Rubisco activase leads to a decrease in Rubisco content, possibly due to post-transcriptional mechanisms.
- Subjects :
- Chlorophyll metabolism
Electrophoresis, Polyacrylamide Gel
Enzyme Activation
Gene Expression Regulation, Plant
Genes, Plant
Light
Nitrogen metabolism
Oryza genetics
Oryza radiation effects
Plant Leaves genetics
Plant Leaves radiation effects
Plant Proteins genetics
Plants, Genetically Modified enzymology
Plants, Genetically Modified genetics
Ribulose-Bisphosphate Carboxylase genetics
Transcription, Genetic
Up-Regulation
Carbon Dioxide metabolism
Oryza enzymology
Photosynthesis
Plant Leaves enzymology
Plant Proteins metabolism
Ribulose-Bisphosphate Carboxylase metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1471-9053
- Volume :
- 53
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Plant & cell physiology
- Publication Type :
- Academic Journal
- Accession number :
- 22470057
- Full Text :
- https://doi.org/10.1093/pcp/pcs042