Natures wonders: Venus fly trap electric trigger (Introduction)

by David Turell , Tuesday, October 17, 2023, 17:32 (401 days ago) @ David Turell

From two ion channels:

https://www.the-scientist.com/news/how-the-venus-flytrap-captures-its-prey-71429?utm_ca...

"How these two light touches trigger abrupt shutting of the leaves has been hypothesized, but never proven. Now, in a new study published in Current Biology, a team of researchers knocked out two ion channels, making it harder to produce action potentials and proving the channels’ importance in leaf closing.1

“'The paper is a very big technical advance,” said plant biophysicist Rainer Hedrich at the University of Wurzburg who was not involved in the study. “It is possible to knock out genes in an excitable plant and test hypotheses.”

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"...recently, scientists found mechanosensitive ion channels FLYCATCHER1 (FLYC1) and FLYCATCHER2 (FLYC2) expressed in trigger hairs that may associate with touch sensitivity.5 Even though the Venus flytrap’s genome is sequenced, no targeted mutations of ion channel genes have been made to conclusively prove their roles in leaf closing.

"So, plant biologists Carl Procko and Joanne Chory at the Salk Institute decided to use CRISPR-Cas9 to mutate FLYC1 and FLYC2 to investigate their functions. Scientists had hypothesized that an insect’s touch causes deformation of the trigger hair’s sensory cell membrane, which causes the opening of these ion channels and membrane depolarization and electrical signaling.

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"He collaborated with molecular neurobiologist Sreekanth Chalasani, also at the Salk Institute, who works with ultrasound. When the team tested the plants with a new, more sensitive assay using ultrasound waves to stimulate the trigger hair, the FLYC1-FLYC2 double mutants showed a significant defect: mutated plants required a greater ultrasound pressure to induce the trap closure than wild type plants. The team noted that single FLYC1 mutants stimulated with ultrasound closed just as well as the wild type plants. Procko believes that brute force mechanical stimulation with the glass rod may be so large that it could act through different mechanosensitive ion channels in the trigger hair.

“'The next step now is to start looking at these other mechanosensitive channels that are within the trigger hair,” said Procko. “We can start to mutate some of these others and put them in various combinations to see exactly which mechanosensitive channels are most important or if they’re all required together to get that very exquisite touch sensitivity of the trigger hair.” Hedrich’s team is currently working to knock out a calcium channel gene hyperosmolality-gated calcium-permeable channel (OSCA).

"Procko acknowledged that he didn’t know exactly how the ultrasound assay relates to touch, which limits the study. “It’s a mechanical stimulus. We like to think it’s related to touch, but it could alternatively be applying that stimulus directly to the sensory membranes and altering the membranes. So, this is still a little bit of a question mark,” said Procko."

Comment: the deeper scientists dig the more complexities appear. The Venus fly trap is a prime example of intelligent design. The plant is irreducibly complex.