This mutant Venus flytrap mysteriously lost its ability to “count” to 5

In 2011, a gardener named Mathias Maier came across an unusual mutant Venus flytrap. Scientists recently discovered that the typical Venus flytrap can actually “count” to five, sparking further research into how plants manage this amazing feat. rice field. A mutant Venus flytrap may hold the key. According to a new paper published in Current Biology, this mutant Venus flytrap does not snap shut in response to stimuli like the typical Venus flytrap.

“This mutant apparently forgot how to count, so I named it dyscalculia (DYSC),” co-author Biology at the Julius-Maximilians-Universität Würzburg (JMU) in Bavaria, Germany. Physicist Reiner Hedrich said. (Previously called “ERROR”.)

As previously reported, the Venus flytrap attracts prey with its pleasant, fruity scent. When an insect perches on a leaf, it stimulates the highly sensitive trigger hairs that line the leaf. When the pressure gets strong enough to bend those hairs, the plant snaps the leaves shut, trapping the insect inside. increase. The insects are slowly digested over a period of 5 to 12 days, after which the traps reopen and release the dried insect shells into the wind.

In 2016, Hedrich led a team of German scientists to discover that Venus flytraps can actually “count” the number of times something touches their hairy leaves. stones, or even dead insects. The scientists hit the leaves of test plants with mechanoelectric pulses of varying intensity and measured the response. The plant detects the first “action potential” but does not snap immediately, waiting until a second zap confirms the presence of actual prey, at which point the trap closes.

Venus flytraps, however, do not close completely and produce digestive enzymes to consume the prey and work until the bristles are triggered three more times (five stimuli total). German scientists likened this action to conducting a rudimentary cost-effectiveness analysis. In this analysis, the size and nutrient content of potential prey that Venus flytraps struggle with in their mouths, as well as the triggering stimulus, help determine whether it is worth the effort. will release the captives within approximately 12 hours.

In 2020, Japanese scientists genetically engineered Venus flytraps to glow green in response to external stimuli, yielding important clues about how plants’ short-term “memory” works. rice field. They introduced the gene for a calcium sensor protein called GCaMP6. GCaMP6 glows green whenever it binds to calcium. Its green fluorescence allowed the researchers to visually track changes in calcium levels when the needles stimulated the plant’s sensitive hairs.

The results supported the hypothesis that the first stimulus caused the release of calcium, but the concentration reached the critical threshold that signals the trap to close without a second influx of calcium from the second stimulus. did not reach However, the calcium concentration decreases over time, so the second stimulus must occur within 30 seconds of he. If he takes more than 30 seconds between the first and the second stimulation, the trap will not close. Thus, while increases and decreases in calcium concentration in leaf cells indeed appear to function as a sort of short-term memory for Venus flytraps, exactly how calcium concentration functions in the plant’s electrical network is unclear. It remains unknown.

Despite being “essentially indistinguishable” from the wild Venus flytrap, that doesn’t seem to be the case with DYSC. The DYSC does not close in response to two sensory stimuli or process prey in response to additional stimuli.Hedrich of course othersI wanted to know why. They purchased wild Venus flytraps and mutant DYSC Venus flytraps and performed parallel experiments. They mechanically stimulated the plants, measured action potentials, and sprayed the plants with a contact hormone called jasmonic acid, which is essential for prey processing.

Hedrich and his team found that the mutation did not appear to affect action potentials or underlying calcium signals during the first two-count phase of the process. The action potential fires, but the trap does not snap closed. This suggests that contact activation of calcium signaling is suppressed. In addition, scientists suspected defects affecting the decoding of calcium signals. Administration of jasmonic acid did not solve the problem of rapid trap closure failure, but restored the ability to handle prey.

Co-author Ines Kreuzer then looked at the gene expression patterns of the mutated genes to find changes that could explain this. She was able to narrow down the possible suspects to a few deciphering components that bind calcium and subsequently modify specific effector proteins: an enzyme called LOX3 is involved in the biosynthesis of jasmonic acid. The next step is to take a closer look at the modified protein and alter its activity when prey comes into contact with DYSC. “Thus, we want to close the circle and look at what plants do to distinguish numbers from each other, that is, how numbers are counted.

DOI: Current Biology, 2023. 10.1016/j.cub.2022.12.058 (About DOI).

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