An isoleucine residue acts as a thermal and regulatory switch in wheat Rubisco activase

Degen, Gustaf E. and Worrall, Dawn and Carmo-Silva, Elizabete (2020) An isoleucine residue acts as a thermal and regulatory switch in wheat Rubisco activase. The Plant Journal, 103 (2). pp. 742-751. ISSN 0960-7412

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Abstract

The regulation of Rubisco, the gatekeeper of carbon fixation into the biosphere, by its molecular chaperone Rubisco activase (Rca) is essential for photosynthesis and plant growth. Using energy from ATP hydrolysis, Rca promotes the release of inhibitors and restores catalytic competence to Rubisco-active sites. Rca is sensitive to moderate heat stress, however, and becomes progressively inhibited as the temperature increases above the optimum for photosynthesis. Here, we identify a single amino acid substitution (M159I) that fundamentally alters the thermal and regulatory properties of Rca in bread wheat (Triticum aestivum L.). Using site-directed mutagenesis, we demonstrate that the M159I substitution extends the temperature optimum of the most abundant Rca isoform by 5°C in vitro, while maintaining the efficiency of Rubisco activation by Rca. The results suggest that this single amino acid substitution acts as a thermal and regulatory switch in wheat Rca that can be exploited to improve the climate resilience and efficiency of carbon assimilation of this cereal crop as temperatures become warmer and more volatile.

Item Type:
Journal Article
Journal or Publication Title:
The Plant Journal
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1300/1311
Subjects:
ID Code:
143781
Deposited By:
Deposited On:
04 May 2020 07:55
Refereed?:
Yes
Published?:
Published
Last Modified:
23 Sep 2020 06:05