Enhanced translation of a chloroplast-expressed RbcS gene restores small subunit levels and photosynthesis in nuclear RbcS antisense plants

Amit Dhingra; Archie R Portis; Henry Daniell

doi:10.1073/pnas.0400981101

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Enhanced translation of a chloroplast-expressed RbcS gene restores small subunit levels and photosynthesis in nuclear RbcS antisense plants

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Enhanced translation of a chloroplast-expressed RbcS gene restores small subunit levels and photosynthesis in nuclear RbcS antisense plants

Amit Dhingra, Archie R Portis and Henry Daniell

Proceedings of the National Academy of Sciences - PNAS, Vol.101(16), pp.6315-6320

04/20/2004

DOI: https://doi.org/10.1073/pnas.0400981101

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https://hdl.handle.net/2376/103650

PMCID: PMC395966

PMID: 15067115

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Abstract

Biological Sciences

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a key enzyme that converts atmospheric carbon to food and supports life on this planet. Its low catalytic activity and specificity for oxygen leads to photorespiration, severely limiting photosynthesis and crop productivity. Consequently, Rubisco is a primary target for genetic engineering. Separate localization of the genes in the nuclear and chloroplast genomes and a complex assembly process resulting in a very low catalytic activity of hybrid Rubisco enzymes have rendered several earlier attempts of Rubisco engineering unsuccessful. Here we demonstrate that the Rbc S gene, when integrated at a transcriptionally active spacer region of the chloroplast genome, in a nuclear Rbc S antisense line and expressed under the regulation of heterologous (gene 10) or native ( psb A) UTRs, results in the assembly of a functional holoenzyme and normal plant growth under ambient CO 2 conditions, fully shortcircuiting nuclear control of gene regulation. There was ≈150-fold more Rbc S transcript in chloroplast transgenic lines when compared with the nuclear Rbc S antisense line, whereas the wild type has 7-fold more transcript. The small subunit protein levels in the gene 10/ Rbc S and psb A/ Rbc S plants were 60% and 106%, respectively, of the wild type. Photosynthesis of gene 10/ Rbc S plants was approximately double that of the antisense plants, whereas that of psb A/ Rbc S plants was restored almost completely to the wild-type rates. These results have opened an avenue for using chloroplast engineering for the evaluation of foreign Rubisco genes in planta that eventually can result in achieving efficient photosynthesis and increased crop productivity.

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Title: Enhanced translation of a chloroplast-expressed RbcS gene restores small subunit levels and photosynthesis in nuclear RbcS antisense plants
Creators: Amit Dhingra - Department of Molecular Biology and Microbiology, University of Central Florida, 4000 Central Florida Boulevard, Biomolecular Science, Building 20, Room 336, Orlando, FL 32816-2364; and
Archie R Portis - Department of Molecular Biology and Microbiology, University of Central Florida, 4000 Central Florida Boulevard, Biomolecular Science, Building 20, Room 336, Orlando, FL 32816-2364; and
Henry Daniell - Department of Molecular Biology and Microbiology, University of Central Florida, 4000 Central Florida Boulevard, Biomolecular Science, Building 20, Room 336, Orlando, FL 32816-2364; and
Publication Details: Proceedings of the National Academy of Sciences - PNAS, Vol.101(16), pp.6315-6320
Academic Unit: Horticulture, Department of
Publisher: National Academy of Sciences
Identifiers: 99900546622301842
Language: English
Resource Type: Journal article