Crassulacean acid metabolism (CAM) is one of the most important watersaving, photosynthetic adaptations acquired by vascular plants. CAM species typically display a 3-fold and 6-fold improvement in water use efficiency (WUE, CO2 fixed per unit water lost) compared with C4 and C3 plants, respectively, under comparable conditions. Metabolon’s metabolic profiling technology provided an unprecedented opportunity to probe plant drought stress responses to reveal the metabolic complexity associated with the CAM adaptation.

More than 6% of vascular plant species perform some degree of CAM to aid in survival in semi-arid tropical and subtropical environments including ecological niches with seasonal or intermittent water availability. Although the basic biochemical sequence required to perform CAM is understood, the metabolic mechanisms associated with the circadian clock control of CAM are less well understood.