The carnivorous plant Genlisea harnesses active particle dynamics to prey on microfauna

TL;DR

Genlisea plants use active particle physics principles to manipulate microfauna and bacteria, enhancing their digestion process through structured environments and concentration gradients, as shown by experiments and simulations.

Contribution

This study reveals a novel mechanism where Genlisea exploits active matter physics to prey on microfauna, combining experimental and simulation evidence.

Findings

Genlisea rectifies bacterial swimming to direct bacteria towards digestion chambers.

Macromolecular digestion products diffuse away, creating concentration gradients.

The mechanism is localized with no large-scale efflux of digested matter.

Abstract

Carnivory in plants is an unusual trait that has arisen multiple times, independently, throughout evolutionary history. Plants in the genus Genlisea are carnivorous, and feed on microorganisms that live in soil using modified subterranean leaf structures (rhizophylls). A surprisingly broad array of microfauna has been observed in the plants' digestive chambers, including ciliates, amoebae and soil mites. Here we show, through experiments and simulations, that Genlisea exploit active matter physics to 'rectify' bacterial swimming and establish a local flux of bacteria through the structured environment of the rhizophyll towards the plant's digestion vesicle. In contrast, macromolecular digestion products are free to diffuse away from the digestion vesicle and establish a concentration gradient of carbon sources to draw larger microorganisms further inside the plant. Our experiments and simulations show that this mechanism is likely to be a localised one, and that no large-scale efflux of digested matter is present.