biostudies-literatureUnknown11Tay IYYYale-NUS CollegeThe evolution of Crassulacean acid metabolism (CAM) is thought to be along a C₃-CAM continuum including multiple variations of CAM such as CAM cycling and CAM idling. Here, we applied large-scale constraint-based modeling to investigate the metabolism and energetics of plants operating in C₃, CAM, CAM cycling, and CAM idling. Our modeling results suggested that CAM cycling and CAM idling could be potential evolutionary intermediates in CAM evolution by establishing a starch/sugar-malate cycle. Our model analysis showed that by varying CO₂ exchange during the light period, as a proxy of stomatal conductance, there exists a C₃-CAM continuum with gradual metabolic changes, supporting the notion that evolution of CAM from C₃ could occur soFrontiers in plant science573197https://www.ebi.ac.uk/biostudies/studies/S-EPMC7874232biostudies-literatureMetabolic Modeling of the C₃-CAM Continuum Revealed the Establishment of a Starch/Sugar-Malate Cycle in CAM Evolution.PMC7874232Cheung CYMOdang KBTay IYYfalseMetabolic Modeling of the C₃-CAM Continuum Revealed the Establishment of a Starch/Sugar-Malate Cycle in CAM Evolution.The evolution of Crassulacean acid metabolism (CAM) is thought to be along a C₃-CAM continuum including multiple variations of CAM such as CAM cycling and CAM idling. Here, we applied large-scale constraint-based modeling to investigate the metabolism and energetics of plants operating in C₃, CAM, CAM cycling, and CAM idling. Our modeling results suggested that CAM cycling and CAM idling could be potential evolutionary intermediates in CAM evolution by establishing a starch/sugar-malate cycle. Our model analysis showed that by varying CO₂ exchange during the light period, as a proxy of stomatal conductance, there exists a C₃-CAM continuum with gradual metabolic changes, supporting the notion that evolution of CAM from C₃ could occur so2020-01-01T00:00:00Z20202025-04-04T11:53:53.385Z2021-02-21T10:03:23ZS-EPMC78742323358474110.3389/fpls.2020.573197