How Plants Evolved to Eat Meat

Pitcher plants across different continents acquired their tastes for meat in similar ways.

Diana Kwon
Feb 6, 2017

AMADA44, WIKIMEDIA The Australian pitcher plant, Cephalotus follicularis, waits patiently for its prey to land on its mouth-like leaves, fall into its slippery pouch, and drown in a cocktail of digestive enzymes. These carnivorous plants may have evolved in similar ways to other, unrelated meat-eating plants around the globe, according to a February 6 study in Nature Ecology and Evolution.

Previous investigations had revealed that Australian pitcher plants are more closely related to the non-carnivorous starfruit, Averrhoa carambola, than pitcher plants from other continents. This suggested that carnivory evolved repeatedly in plants, likely to cope with nutrient-scarce soils, Victor Albert, a plant-genome scientist at the University of Buffalo told Nature. “What they’re trying to do is capture nitrogen and phosphorus from their prey,” he added.

Albert and colleagues sequenced the Australian pitcher plant’s genome and compared the DNA in the plant’s carnivorous and non-carnivorous photosynthetic leaves. Their analyses revealed genetic changes associated with prey capture and digestion. “According to the results, leaves that catch insects have gained new enzymatic functions,” Julio Rozas, a study co-author and professor at the University of Barcelona, said in a statement. These includes chitinase, an enzyme that breaks down the chitin in insects’ exoskeletons, and purple acid phosphatase, which helps release phosphate from the prey, Rozas explained.

When the group compared Australian pitcher plant’s digestive fluid to that of three unrelated carnivorous plants, the results suggested that—despite the fact that the plants evolved separately—their digestive enzymes had similar genetic origins. “In a number of cases, the very same genes from non-carnivorous ancestors have been recruited for carnivorous purposes," Thomas Givnish, who studies plant evolution at the University of Wisconsin who was not involved in the study, told NPR.

In an interview with NPR, Albert added: "The pathways to evolving a carnivorous plant, and in particular, to a pitcher plant, may be very restricted.”