Sundew carnivory evolved from defence mechanisms

Last updated: 21 Feb, 2017

For centuries, researchers have been fascinated with the rapid prey responses of carnivorous plants, believing them to have evolved from plant defence mechanisms. In their recent paper, published in New Phytologist, Miroslav Krausko and colleagues confirmed this hypothesis, using mechanical, prey, and wounding stimuli to demonstrate that the Cape sundew (Drosera capensis) uses electrical and hormonal signals in both responses, but distinguishes between herbivorous attackers and new victims with specific patterns of signalling.

After the sticky mucilage secreted from the tentacles on a sundew leaf catches an unsuspecting insect, the leaf bends around its victim to increase its grip on the prey. Previous work has shown that electrical signals and a group of phytohormones called jasmonates play central roles in this leaf bending in response, but these signals are also used in the wounding response, so how do plants distinguish between the two stimuli?

Krausko et al. revealed that wounding the leaves sets off a systemic defence response throughout the entire plant, while the insect prey resulted in a very localised pattern of electrical signalling and jasmonate accumulation. While wounding initiated a false alarm that began a minor secretion of digestive enzymes, the plant digestive juices really started flowing when they detected chemicals released from a true insect victim.

These findings confirm that the carnivory and defence mechanisms in plants are related, but that the full prey response is only triggered by the proper patterning of electrical and jasmonate signals, along with chemical stimuli from the victim itself.

Read the paper:

Krausko, M., Perutka, Z., Šebela, M., Šamajová, O., Šamaj, J., Novák, O. and Pavlovič, A. (2016). The role of electrical and jasmonate signalling in the recognition of captured prey in the carnivorous sundew plant Drosera capensis. New Phytologist. doi: 10.1111/nph.14352.

What to read next:

• Read the full version of this article on the New Phyt blog
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• How the Venus flytrap extracts energy from its prey's nitrogen compounds
  The carnivorous plant captures prey for more than nutritional purposes.

Sarah Jose

@JoseSci