Purslane, a common weed native to Asia, has been found to contain information on how to create drought-resistant crops.
Purslane ( Portulaca oleracea) is a herb that is native to Asia but has spread all across the world. It is commonly found in cleared areas. The purslane herb has red stems and fleshy green leaves, similar to the spekboom. The flowers are a bright yellow.
Scientists from Yale University found that purslane integrates two very distinct metabolic pathways to create a novel type of photosynthesis that enables the plant to endure drought while still remaining highly productive.
“This is a very rare combination of traits and has created a kind of ‘super plant', one that could be potentially useful in endeavours such as crop engineering,” said Erika Edwards, Yale professor of ecology and evolutionary biology and senior author of the paper published on Friday in the journal Science Advances.
The study explained that “plants have independently evolved a variety of distinct mechanisms to improve photosynthesis. For instance, corn and sugarcane evolved what is called C4 photosynthesis, which allows the plant to remain productive under high temperatures.”
Succulents possess another type called CAM photosynthesis, which helps them survive in deserts and other areas with little water. Both C4 and CAM serve different functions, but recruits use the same biochemical pathway to act as “add-ons” to regular photosynthesis.
Purslane was found to be unique in that it possesses both these mechanisms, which allow it to be not only drought resistant but highly productive as well. Most scientists believe that C4 and CAM operated independently within the leaves of purslane.
But, this was not the case. The Yale team, led by co-corresponding authors and postdoctoral scholars Jose Moreno-Villena and Haoran Zhou, conducted a spatial analysis of gene expression within the leaves of purslane and found that C4 and CAM activity are totally integrated, operating in the same cells, with products of CAM reactions being processed by the C4 pathway.
This system provides unusual levels of protection for a C4 plant in times of drought.
“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.”
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