Specific protein helps insect-eating plants trap their prey

A Venus flytrap will shut immediately just at the brush of an insect’s wing; however, the biology of how these plants are able to sense and react to touch is yet to be properly understood, particularly at the molecular level.

Video Credit: Salk Institute.

A new study performed by researchers from the Salk Institute and the Scripps Research Institute has discovered what seems to be a crucial protein that plays a role in touch sensitivity in many carnivorous plants, including flytraps.

The results, published in the eLife journal on March 16^th, 2021, help describe a crucial process that has confounded botanists for a long time. These could provide researchers with a better understanding of how different kinds of plants perceive and respond to mechanical stimulation. The study may also have a promising application in medical treatments that mechanically activate human cells, like neurons.

We know that plants sense touch. The Venus flytrap, which has a very fast response to touch, provides an opportunity to study a sensory modality that historically has been poorly understood.”

Joanne Chory, Study Co-Corresponding Author and Director, Plant Molecular and Cellular Biology Laboratory, Salk Institute

Chory also holds the Howard H. and Maryam R. Newman Chair in Plant Biology.

For a long time, scientists have been fascinated by carnivorous plants, including the Venus flytraps; Charles Darwin had dedicated an entire book to these carnivorous plants. However, while earlier studies have investigated the structural mechanism of their unusual leaves, little is known about how they function at the cellular level.

That is partly because flytraps are difficult to analyze. They grow very slowly and, until recently, the flytrap genome had not been sequenced, paving the way for deeper genetic research.

Because they’re so unusual, people have been interested in these plants for hundreds of years, so there’s quite a bit known about them at the gross, macroscopic level, but the molecular details have been hard to tease out.”

Carl Procko, Staff Scientist, Plant Molecular and Cellular Biology Laboratory, Salk Institute

In the latest study, the researchers grew cloned flytraps from cuttings to get genetically identical plants. Later, they carefully removed thousands of tiny, touch-sensitive trigger hairs from these plants and employed sequencing technology to detect which kinds of proteins were most abundant in the microscopic hairs.

On the basis of previous research work, the researchers knew that the proteins that play a role in sensing touch probably have the ability to move an electrical current over the cell. And indeed. this protein type was the second most common one present in the hairs. The team called this novel protein FLYCATCHER1.

To test this protein, collaborators from the Scripps Research Institute placed it into mammalian cells. The cells reacted by generating an electrical current when touched, demonstrating that the protein is responsive to mechanical stimuli.

The researchers identified the same kind of protein in the tentacles of sundew—a carnivorous plant closely associated with the Venus flytrap. These sticky tentacles in the sundew feel the movement of a struggling insect, activating the leaf to curl up and catch its prey.

These findings are further evidence that the FLYCATCHER1 protein plays a critical role in the trigger hairs of the Venus flytrap and the mechanisms of the plant that sense and respond to touch.”

Joanne Chory, Study Co-Corresponding Author and Director, Plant Molecular and Cellular Biology Laboratory, Salk Institute

As a subsequent step, the team wants to perform a “knockout” test and develop genetically modified flytraps that lack the specific protein. If these flytraps are incapable of sensing touch, it will conclusively establish that the FLYCATCHER1 protein is responsible.