According to Julio Rozas, from the Genetics, Microbiology and Statistics department of the UB, “the ability of carnivorous plants to eat animals in impoverished soils is the result of the action of natural selection that has promoted several genetic changes on the same set of genes. With comparative analysis of genes that are differentially expressed in the two types of leaves, this research has identified the genetic changes associated with the carnivorous diet in plants. “
An example of evolutionary convergence
Genetic analysis shows that, during their evolution towards the carnivorous diet, the leaves that trap insects have acquired new enzymatic functions. There is a specific group of proteins that have evolved to act as digestive enzymes, according to Pablo Librado, another of the authors, who works at the Center for Geogenetics at the University of Copenhagen. Over time, in all three species, the plant protein families that originally aided in self-defense against disease and other threats became today’s digestive enzymes, such as basic chitinase – capable of breaking down chitin, the main component of prey exoskeletons -, and purple acid phosphatase – which allows plants to obtain phosphorus from decomposed bodies.
It is as if these plants had a genetic toolbox and tried to find an answer to become carnivorous. In the end, they all come to the same solution. The case of insectivorous plants is a clear example of evolutionary convergence, probably due to the strong biological restrictions imposed by extreme ecosystems.
Reference: Kenji Fukushima et al. “Genome of the pitcher plant Cephalotus reveals genetic changes associated with carnivory” NatureEcology & Evolution February 6, 2017