11.2.3. Designing Carbon Conserving Photorespiration

Photorespiratory bypass to eliminate the loss of CO2 can be designed by incorporating synthetic routes through metabolic engineering. The reduction of glycolate to glycolaldehyde is a promising approach as it can assimilate 2-phosphoglycolate into the Calvin cycle without the loss of carbon. Screening the germplasm for highly stable and substratespecific enzymes, such as acetyl-CoA synthetase and propionyl-CoA reductase, would help in favoring the reduction process over oxidation and generating a carbon-conserving pathway [125].

11.2.4. Engineering for Low Emission of Biogenic Volatile Organic Compounds

Plants release a considerable fraction of the assimilated carbon as biogenic volatile organic compounds (BVOCs). Temperature within the range of 20–40 ◦C has a strong influence on the activity of enzymes involved in the biosynthesis of BVOCs like isoperenes, monoterpenes, acetaldehyde, and (E)-2-hexenal. Though BVOCs impart thermal tolerance

at high temperature [126,127], it happens at the cost of 10% of fixed carbon loss. Engineering cultivars with reduced emissions of BVOCs can act as a promising strategy to save carbon under high temperatures.
