The relative abundance of wheat Rubisco activase isoforms is post‑transcriptionally regulated

A - Papers appearing in refereed journals

Perdomo, J. A., Buchner, P. H. and Carmo-Silva, E. 2021. The relative abundance of wheat Rubisco activase isoforms is post‑transcriptionally regulated. Photosynthesis Research.

AuthorsPerdomo, J. A., Buchner, P. H. and Carmo-Silva, E.

Diurnal rhythms and light availability affect transcription–translation feedback loops that regulate the synthesis of photosynthetic proteins. The CO2-fixing enzyme Rubisco is the most abundant protein in the leaves of major crop species and its activity depends on interaction with the molecular chaperone Rubisco activase (Rca). In Triticum aestivum L. (wheat), three Rca isoforms are present that differ in their regulatory properties. Here, we tested the hypothesis that the relative abundance of the redox-sensitive and redox-insensitive Rca isoforms could be differentially regulated throughout light–dark diel cycle in wheat. While TaRca1-β expression was consistently negligible throughout the day, transcript levels of both TaRca2-β and TaRca2-α were higher and increased at the start of the day, with peak levels occurring at the middle of the photoperiod. Abundance of TaRca-β protein was maximal 1.5 h after the peak in TaRca2-β expression, but the abundance of TaRca-α remained constant during the entire photoperiod. The redox-sensitive TaRca-α isoform was less abundant, representing 85% of the redox-insensitive TaRca-β at the transcript level and 12.5% at the protein level. Expression of Rubisco large and small subunit genes did not show a consistent pattern throughout the diel cycle, but the abundance of Rubisco decreased by up to 20% during the dark period in fully expanded wheat leaves. These results, combined with a lack of correlation between transcript and protein abundance for both Rca isoforms and Rubisco throughout the entire diel cycle, suggest that the abundance of these photosynthetic enzymes is post-transcriptionally regulated.

KeywordsRubisco; Rubisco activase; Gene expression; Protein abundance; Diel cycle
Year of Publication2021
JournalPhotosynthesis Research
Digital Object Identifier (DOI)
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or code[20:20 Wheat] Maximising yield potential of wheat
Designing Future Wheat - WP1 - Increased efficiency and sustainability
Publisher's version
Output statusPublished
Publication dates
Print01 Apr 2021
Publication process dates
Accepted11 Mar 2021

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