Scientists decode evolutionary pathway of pitcher plants

A group of scientists identified the evolutionary pathway that led some plants to turn carnivorous. The finding explains why pitcher plants from different parts of the world appear strikingly similar despite having evolved independently.

The findings were published on 6 February 2017 in the journal Nature Ecology and Evolution.

The findings:

• It suggests that there are only limited pathways for becoming a carnivorous plant.

• The path to carnivory was remarkably similar for the three species examined. These species are Cephalotus follicularis (Australian pitcher plant, related to starfruit), Nepenthes alata (Asian pitcher plant, related to buckweat) and Sarracenia purpurea (American pitcher plant, related to kiwifruit).

• A genetic analysis, which included sequencing the entire genome of Cephalotus, was conducted on these three species.

• The analysis found strong evidence that each of the plants, during their evolution into carnivores, chose many of the same ancient proteins to create enzymes for digesting prey.

• With time, plant protein families that originally assisted in self-defence against disease and other stresses developed into the digestive enzymes. These enzymes include basic chitinase, which breaks down chitin, and purple acid phosphatise from victims' body parts. Chitin is the major component of insects' hard exterior exoskeletons. The purple acid phosphatise enables plants to obtain phosphorus, which is a critical nutrient.

• In a fourth carnivorous species, the Drosera adelae, a relative of Nepenthes that is not a pitcher plant, the enzymes also appeared to share this evolutionary road.

About Pitcher Plant

• Pitcher plants are several different carnivorous plants.

• They have modified leaves known as pitfall traps. The pitfall traps are prey-trapping mechanism featuring a deep cavity filled with digestive fluid liquid.

• The pitcher plant usually refers to members of the Nepenthaceae and Sarraceniaceae families. However, similar pitfall traps are employed by the monotypic Cephalotaceae and some members of the Bromeliaceae.