Alternatives to photorespiration: A system-level analysis reveals mechanisms of enhanced plant productivity.

Photorespiration causes a substantial decrease in crop yield because of mitochondrial decarboxylation. Alternative pathways (APs) have been designed to relocate the decarboxylation step or even fix additional carbon. To improve the success of transferring those engineered APs from model species to crops, we must understand how they will interact with metabolism and how plant physiology affects their performance. Here, we used multiple mathematical modeling techniques to analyze and compare existing AP designs. We show that carbon-fixing APs are the most promising candidates to replace native photorespiration in major crop species. Our results demonstrate the different metabolic routes that APs use to increase yield and which plant physiology can profit the most from them. We anticipate our results to guide the design of new APs and to help improve existing ones.