Poster Presentation International Plant Molecular Biology Conference 2024

Exploring the diversity and evolutionary landscape of Rubisco Activase to enhance photosynthesis. (#195)

Hanjun Sun 1 , Spencer Whitney 1
  1. Plant Science Research School of Biology, Australian National University, Acton, ACT, Australia

Securing food supply from global warming induced heat stress requires developing crops with enhanced heat-tolerance [1]. Rubisco activase (Rca) is a chaperone responsible for the metabolic repair of the photosynthetic CO2-fixing enzyme Rubisco via ATP hydrolysis that displaces inhibitory sugar phosphate molecules from Rubisco catalytic sites. Thermal denaturation of Rca happens at a physiologically relevant temperatures and therefore reduces Rubisco activity and hence photosynthesis [2]. Improving the thermostability of Rca is therefore considered a viable target for helping improve plant heat tolerance. While thermostable variants of Rca exist in nature, little is known about the temperature kinetics of Rca in many crop plants [3, 4]. To address this, my project seeks to compare the ATP turnover rate, Rubisco reactivation efficiency and Rubisco compatibility of Rca variants from a variety of monocot and dicot plant species toward the ultimate aim of identifying structural changes that enhance the temperature kinetics and stability of Rca and test these through transgenic modification in tobacco. An update on our Rca biochemical screening and plant transformation activities will be provided.

  1. Rosenzweig, C., et al., Climate Change and Extreme Weather Events; Implications for Food Production, Plant Diseases, and Pests. Global Change and Human Health, 2001. 2(2): p. 90-104.
  2. Qu, Y., O. Mueller-Cajar, and W. Yamori, Improving plant heat tolerance through modification of Rubisco activase in C3 plants to secure crop yield and food security in a future warming world. Journal of Experimental Botany, 2022.
  3. Scafaro, A.P., et al., A single point mutation in the C-terminal extension of wheat Rubisco activase dramatically reduces ADP inhibition via enhanced ATP binding affinity. Journal of Biological Chemistry, 2019. 294(47): p. 17931-17940.
  4. Scafaro, A.P., et al., A Conserved Sequence from Heat-Adapted Species Improves Rubisco Activase Thermostability in Wheat. Plant Physiology, 2019. 181(1): p. 43-54.