FIGURE 4.

A simplified scheme highlighting tested ways to increase photosynthesis and crop yield by overexpressing selected Calvin cycle enzymes and by creating synthetic chloroplastic photorespiratory bypasses. The enzymes in green circles/squares have been overexpressing either individually or together. Details of the different photorespiratory pathways can be found in the main text: 1 is based on the bacterial glycerate pathway leading to 3-PGA from glycolate (Kebeish et al., 2007; Dalal et al., 2015), 2 is an incomplete glycerate pathway leading to glyoxylate from glycolate (Nölke et al., 2014), 3 are pathways leading to the production of CO₂ from glycolate (Maier et al., 2012; Shen et al., 2019; South et al., 2019). The transporter in the red circle was repressed to improve photorespiratory bypasses (see South et al., 2019). Abbreviations can be found in the main text.