A common plant may provide crucial information on how to create crops resistant to drought in a world affected by climate change. Yale researchers describe how Portulaca oleracea, commonly known as purslane, integrates two different metabolic pathways to produce a novel type of photosynthesis that enables the weed to withstand drought while remaining highly productive in a report published on August 5 in the journal Science Advances.
The weed purslane is unique because it can be very productive and drought tolerant, which is an uncommon combination for a plant. This is because it has both of these evolutionary adaptations. Most scientists believed that C4 and CAM performed different functions inside purslane leaves.
However, co-corresponding authors and postdoctoral researchers Jose Moreno-Villena and Haoran Zhou led the Yale team. They conducted a spatial analysis of gene expression in purslane leaves and found that C4 and CAM activity is entirely integrated. The C4 pathway processes the byproducts of CAM processes, and they both work in the same cells. This method provides a C4 plant with extraordinarily high levels of protection against drought.
The researchers also created metabolic flow models that predicted the development of an integrated C4+CAM system that agreed with their actual findings. The authors speculate that by better understanding this unusual metabolic mechanism, scientists may devise novel strategies for designing crops like corn to withstand prolonged drought.