The Costs of Photorespiration to Food Production Now and in the Future

Abstract

Photorespiration is essential for C 3 plants but operates at the massive expense of fixed carbon dioxide and energy. Photorespiration is initiated when the initial enzyme of photosynthesis, ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco), reacts with oxygen instead of carbon dioxide and produces a toxic compound that is then recycled by photorespiration. Photorespiration can be modeled at the canopy and regional scales to determine its cost under current and future atmospheres. A regional-scale model reveals that photorespiration currently decreases US soybean and wheat yields by 36% and 20%, respectively, and a 5% decrease in the losses due to photorespiration would be worth approximately $500 million annually in the United States. Furthermore, photorespiration will continue to impact yield under future climates despite increases in carbon dioxide, with models suggesting a 12-55% improvement in gross photosynthesis in the absence of photorespiration, even under climate change scenarios predicting the largest increases in atmospheric carbon dioxide concentration. Although photorespiration is tied to other important metabolic functions, the benefit of improving its efficiency appears to outweigh any potential secondary disadvantages.

Bile Acid Sodium Symporter BASS6 Can Transport Glycolate and Is Involved in Photorespiratory Metabolism in Arabidopsis thaliana

“…Also, refixing the CO 2 molecule released during photorespiration consumes additional ATP and NADPH. As a result, photorespiration under current atmospheric CO 2 concentrations results in a significant drag of ;15 to 50% on C3 photosynthetic efficiency depending upon the regional growing season temperature (Ogren, 1984;Peterhansel et al, 2010;Walker et al, 2016b). Losses in yield due to photorespiration are estimated to total ;150 trillion calories per year in midwestern US soybean (Glycine max) and wheat (Triticum aestivum) production alone (Walker et al, 2016b).…”

“…As a result, photorespiration under current atmospheric CO 2 concentrations results in a significant drag of ;15 to 50% on C3 photosynthetic efficiency depending upon the regional growing season temperature (Ogren, 1984;Peterhansel et al, 2010;Walker et al, 2016b). Losses in yield due to photorespiration are estimated to total ;150 trillion calories per year in midwestern US soybean (Glycine max) and wheat (Triticum aestivum) production alone (Walker et al, 2016b). In addition, photorespiration has similar negative impacts on other major C3 crops such as rice (Oryza sativa) and potato (Solanum tuberosum; Sharkey, 1988;Zhu et al, 2010).…”

Lack of GLYCOLATE OXIDASE1, but Not GLYCOLATE OXIDASE2, Attenuates the Photorespiratory Phenotype of CATALASE2-Deficient Arabidopsis

“…However, apart from its greenhouse properties, CO 2 and its photosynthetic assimilation into biomass are the primary foundation of life on Earth. Thus, atmospheric CO 2 content has a direct effect on agricultural production, and even a modest CO 2 increase might in theory result in higher crop yields, especially in plants with C3-type photosynthesis (Walker et al, 2016). In contrast to C4 and CAM-type plants, C3 plants do not possess carbon concentrating mechanisms, and the first stable CO 2 assimilation product is 3-phosphoglycerate that is further processed in the Calvin-Benson cycle to fuel sugar synthesis.…”

“…This oxygenation reaction initiates the photorespiratory pathway that recycles PG back to 3-phosphoglycerate with the release of CO 2 in a series of enzymatic steps distributed between chloroplasts, peroxisomes, and mitochondria (Timm et al, 2008;Bauwe et al, 2012). The metabolic flux through the photorespiratory pathway increases substantially under adverse environmental conditions, such as drought and heat, which ultimately result in a loss of assimilated CO 2 and a consequent yield reduction (Walker et al, 2016).…”

The Sclerophyllous Eucalyptus camaldulensis and Herbaceous Nicotiana tabacum Have Different Mechanisms to Maintain High Rates of Photosynthesis

“…Using the basic equation of leaf carbon dioxide gas exchange and Rubisco specificity for carboxylation relative to oxygenation (von Caemmerer and Farquhar, 1981; Sharkey, 1988; Walker et al, 2016), the rate of Rubisco carboxylation ( V c ) and that of Rubisco oxygenation ( V o ) are calculated according to. $\begin{array}{c}left{V}_c=\frac{A_{\text{n}}+ R_{\text{d}}}{1-({\Gamma }^{*}/C_{\text{c}})}\\ V_o=\frac{A_{\text{n}}+ R_{\text{d}}}{(C_{\text{c}}/2{\Gamma }^{*})-0.5}\end{array}$ where A n represented the net rate of CO 2 assimilation, R d was the rate of mitochondrial respiration as measured after 30 min of dark adaptation, Γ * was the CO 2 compensation point in the absence of daytime respiration (Farquhar et al, 1980; Brooks and Farquhar, 1985), and C c was the chloroplast CO 2 concentration.…”