Can a common weed help drought-proof our food supply?

As climate change sees rising temperatures and widespread droughts, worries about our futures have understandably been growing. With food production at risk until 2023 from the scorching summer countries have been facing across the world, it’s easy to panic. But don’t fret yet – a Yale University study on the succulent plant Portulaca oleracea, commonly known as purslane or little hogweed, has provided some hope.

The Food and Agricultural Organisation (FAO) estimates that one in three people worldwide face food insecurity – and the population continues to grow. To make progress against hunger, it is vital to not only tackle climate change, but also to use less land for crops. In other words – work smarter, not harder.

Researchers from Yale University have discovered that the purslane plant thrives in hot, dry conditions, meaning it could potentially be resistant to the effects of global warming. Using two rare types of photosynthesis, Purslane could help scientists engineer crops that can withstand climate change.

Most plants use one type of photosynthesis, but purslane uses both C4 photosynthesis and CAM photosynthesis. The former allows plants to thrive in high temperatures, such as sugarcane and corn, while the latter helps a plant survive with little water, like succulents in deserts. Therefore, purslane can remain highly productive in both droughts and heatwaves, which is a rarity.

Originally, scientists believed that the two types of photosynthesis worked independently in the plant’s leaves – but the Yale study shows that they actually operate in the same cells, working together as a single metabolic system. This process could be used to engineer plants to become both drought resistant and heat tolerant. For example, scientists could take a C4 crop such as sugarcane, and make it use CAM photosynthesis as well.

Yale’s Erika Edwards, professor of ecology and evolutionary biology and senior author of the paper, said, “In terms of engineering a CAM cycle into a C4 crop, such as maize, there is still a lot of work to do before that could become a reality,” said Edwards. “But what we’ve shown is that the two pathways can be efficiently integrated and share products. C4 and CAM are more compatible than we had thought, which leads us to suspect that there are many more C4+CAM species out there, waiting to be discovered.”