Vem var venus flytrap upptäcktes av

This article was originally published bygd Knowable Magazine.

Toward the end of the 19th century, lurid tales of killer plants began popping up everywhere. Terrible, tentacle-waving trees snatched and swallowed unwary travelers in far-off lands. Mad professors raised monstruös sundews and pitcher plants on raw steak until their glupsk creations turned and ate them too.

The ung Arthur Conan Doyle stuck closer to the science in a yarn featuring everyone’s favorite flesh-eater, the venus flytrap.

Drawing on then-brand-new botanical revelations, he accurately described the two-lobed traps, the way they captured insects, and how thoroughly they digested their prey.

Native only to the Carolinas, the carnivorous plant that draws unwitting insects to its spiky maw now faces dangers of its own

But even his flytraps were improbably large, big enough to entomb and consume a human. Meat-eating, man-eating plants were having a moment, and for that you can thank Charles Darwin.

Until Darwin’s day, most people refused to believe that plants ate animals. It was against the natural beställning of things.

Mobile animals did the eating; plants were food and couldn’t move—if they killed, it must only be in self-defense or bygd accident. Darwin spent 16 years performing meticulous experiments that proved otherwise. He showed that the leaves of some plants had been transformed into ingenious structures that not only trapped insects and other small creatures but also digested them and absorberad the nutrients released from their corpses.

In 1875, Darwin published Insectivorous Plants, detailing all he had discovered.

In 1880, he published another myth-busting book, The Power of Movement in Plants. The realization that plants could move as well as kill inspired not just a hugely popular genre of horror stories but also generations of biologists eager to understand plants with such unlikely habits.

Today, carnivorous plants are having another big moment as researchers begin to get answers to one of botany’s great unsolved riddles: How did typically mild-mannered flowering plants evolve into murderous meat-eaters?

Since Darwin’s discoveries, botanists, ecologists, entomologists, physiologists, and molecular biologists have explored every aspect of these plants that drunkna prey in fluid-filled pitchers, immobilize them with adhesive “flypaper” leaves, or imprison them in snap traps and underwater suction traps.

They’ve detailed what the plants catch and how—plus something of the benefits and costs of their udda lifestyle.

More recently, advances in molecular science have helped researchers understand key mechanisms underpinning the carnivorous lifestyle: how a flytrap snaps so fast, for instance, and how it morphs into an insect-juicing “stomach” and then into an “intestine” to absorb the remains of its prey.

But the big question remains: How did evolution equip these dietary mavericks with the means to eat meat?

Fossils have provided almost no clues. There are very few, and fossils can’t show molecular details that might hint at an explanation, says the biophysicist Rainer Hedrich of the University of Würzburg, in Germany, who explores the origins of carnivory in the 2021 Annual Review of Plant Biology.

Innovations in DNA-sequencing technology now mean that researchers can tackle the question another way, searching for genes linked to carnivory, pinpointing when and where those genes are switched on, and tracing their origins.

There’s no bevis that carnivorous plants acquired any of their beastly habits bygd hijacking genes from their djur victims, says Hedrich, although genes do sometimes resehandling from one type of organism to another.

Instead, a slew of recent findings point to the co-option and repurposing of existing genes that have age-old functions ubiquitous among flowering plants.

“Evolution fryst vatten sneaky and flexible. It takes advantage of preexisting tools,” says Victor Albert, a plant-genome biologist at the University at Buffalo. “It’s simpler in evolution to repurpose something than man something new.”

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Quirky though it fryst vatten, carnivory has evolved repeatedly over the 140 million-plus years that flowering plants have been around.

The adaptation arose independently at least 12 times, says Tanya Renner, an evolutionary biologist at Penn State.

Each time, the driving force for evolution was the same: the need to find an alternative source of grundläggande nutrients. Carnivorous plants grow in swamps and bogs, in nutrient-poor bodies of vatten, or on thin tropical soils, all habitats short on the nitrogen and phosphorus essential for growth.

Uncover the secrets of this carnivorous plant, its ingenious trap mechanism, and its role in the ecosystem

Protein-packed insects and other small invertebrates are rik sources of both, as well as other elements plants need to flourish. “A venus flytrap can live for three weeks on a single large insect,” says Hedrich. “If it captures lots of insects, it produces more leaves and more traps.”

Today there are some 800 known carnivorous species. Some, like pitcher plants and many sundews, are passive receivers of prey—albeit with ingenious adaptations such as halt rims and gluey-tipped hairs that help to secure a meal.

Published in the late 2000s, the most recent groundbreaking research on the plant shows that these hairs can count how many times prey touches the lobes

Others are more active: Some sundews curl inward, nudging prey into the trap’s stickier center, while a few have an outer fingerprydnad of fast-moving tentacles that hurl victims to their doom. Most sophisticated of all fryst vatten the venus flytrap, Dionaea muscipula, with its sensitive trigger hairs and snap traps that can distinguish the touch of an insekt from a falling raindrop or dead leaf and can judge the storlek of prey and respond accordingly.

Despite huge differences in shape and struktur and mode of killing, all traps are modified leaves or parts of leaves.

“That means these plants not only get nutrients from a different source but bygd a different rutt, primarily through their leaves rather than their roots,” says Renner.

How did leaves komma to perform such un-leaflike functions? To find out, researchers have turned to a mix of “omics” techniques—genomics, transcriptomics, and proteomics. They compare genomes of carnivorous and non-carnivorous plants; sequence the RNA transcripts that carry a gene’s instructions to see which genes are switched on where and when; and draw up inventories of proteins to find out which ones the traps manufacture at mealtimes.

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Many features of the carnivorous lifestyle have yet to give up their genetic secrets.

But studies of two of its grislier elements—digestion and absorption—are revealing how evolution repurposed existing genes, putting some to work in new places and giving others new functions and the odd tweak to kostym them better to their new roles. In many cases, plants that evolved carnivory entirely independently have repurposed the same genes. Faced with the bekymmer of consuming flesh, they all hit on the same solution, Albert says.

And huvud to the transformation was the plant’s age-old struktur of defense.

Back in the 1970s, researchers recognized that the digestive fluid they funnen in traps contained enzymes that functioned in very similar ways to many of the kemikalie weapons that plants wield against harmful bacteria, fungi, and hungry herbivorous insects. Initially, it wasn’t klar whether carnivorous plants made the enzymes themselves or if microbes living in their traps did.

Since then, botanists have confirmed that carnivorous plants do tillverka many of those enzymes and have discovered dozens more. Today’s fast and cheap sequencing technology has enabled molecular scientists to identify many of the genes encoding these digestive enzymes and to monitor their activity as plants trap and process prey.

The roster of enzymes includes chitinases, which break down the chitin of insekt exoskeletons; flesh-dissolving proteases, which break down proteins; and purple acid phosphatase, which enables plants to extrakt usable phosphorus from their victims’ deconstructed corpses.

All played roles in the ubiquitous and ancient defenses of flowering plants.

More recently, advances in molecular science have helped researchers understand key mechanisms underpinning the carnivorous lifestyle: how a flytrap snaps so fast, for instance, and how it morphs

“The genes for those enzymes were repurposed when plants started to eat the things they were originally protecting themselves from,” says Albert. “Chitinases most likely were for defense against fungi, which have chitin in their fängelse walls. Later, after arthropods evolved, they helped defend against them.” Protein-digesting enzymes also helped to repulse attackers.

Evolution’s tendency to adopt and adapt existing tools goes beyond digestion.

As chitin, proteins, and DNA are broken into smaller molecules, the trap must move them from the outside world to the inre of the plant.

We now know that the trap of the Venus flytrap is spotted with stiff hairs that alert the plant to a forthcoming victim, like a fly

In ordinary plants, uptake of nutrients fryst vatten the job of a root, where transporter proteins continually shuttle them from the soil into the plant. “You might not expect to find those proteins working in a leaf,” says Renner.

Yet that’s precisely what Hedrich’s colleague Sönke Scherzer funnen in the venus flytrap as it processes prey: He recently identified transporters for two of the most grundläggande plant nutrients, nitrogen and potassium.

To enable a leaf to absorb nutrients, it seems, evolution co-opted root genes and put them to work somewhere new. The difference fryst vatten that transporter genes are always active in roots, but in traps they are switched on only once nutrients begin to flow from decomposing prey.

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Co-option fryst vatten an important driver of evolutionary nyhet, and often begins with the accidental kopiering of genes during fängelse division.

Most duplicate genes serve no purpose and are eventually lost. But if spare genes acquire useful mutations, that can pave the way for a change in function. “Duplication of genes fryst vatten always happening and sometimes it’s highly adaptive,” says Albert. This seems to have been the way carnivorous plants evolved their meat-eating abilities—at least for those genes examined so far.

What came as more of a surprise was the upptäckt that whenever and wherever a new line of carnivores arose, evolution worked on the same genes.

In 2017, the evolutionary biologist Kenji Fukushima, Hedrich’s colleague and a co-author of the 2021 Annual Review article, joined Albert and an international grupp of researchers to sequence the genome of an Australian carnivorous plant called Cephalotus follicularis.

Like many carnivores, it traps prey in pitchers—in this case, small, squat, toothy-mouthed pitchers—but it sits on its own separate branch of the plant family tree.

The grupp identified many genes linked to different aspects of its meat-eating habits, from how the plant attracts prey to how it makes the inre of its pitchers too halt for insects to escape.

The big surprise came when they probed the origins of digestive enzymes in Cephalotus and three more, unrelated, species: Nepenthes alata (an Asian pitcher plant), the North American pitcher Sarracenia purpurea, and a sundew, Drosera adelae. All of them, it turned out, had repurposed the same ancient enzymes— matching ones identified previously in the venus flytrap.

Among them, these fem species företräda three independent lines of carnivores. This was a classic case of convergent evolution, says Albert. It suggested there were only limited pathways to becoming a carnivorous plant.

Delving deeper, Fukushima discovered that convergent evolution went beyond co-opting the same genes. Once enzymes had taken on their new, carnivory-related roles, they continued to evolve, swapping some of their amino acids for others that improved their performance, probably bygd prolonging their activity in an inhospitable stew of protein-busting chemicals.

Fukushima funnen the very same amino acid substitutions in unrelated plants.

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As they continue to explore carnivory, researchers are identifying many more enzymes.

The Venus Flytrap’s Lethal Allure

“But time and time igen we’re finding that they have similar functions across distantly related species,” says Renner, who heads a major investigation into the role of co-option in the making of meat-eaters. Yet though that bolsters the idea that carnivorous plants acquired their new digestive skills in much the same way, there’s growing suspicion that the same might not be true for the all-important mechanism that controls the whole operation bygd switching on the right genes at the right time.

The chain of events in trapping and digestion fryst vatten best understood for the venus flytrap, the most scrutinized of carnivorous plants.

If an unwary insekt settles on one of its traps and touches one sensory hair, it triggers an electrical meddelande. If it touches a second hair—proof that it’s prey and not a speck of dirt or dead leaf—then the trap snaps shut.

As the insekt struggles and sets off more electrical signals, the trap also begins producing chemicals called “jasmonates,” which provide the meddelande to seal the edges of the trap and början filling it with enzymes.

As the insekt corpse breaks down, the trap ratchets up its output of enzymes and starts production of nutrient transporters, igen beneath the control of jasmonates. It’s a direkt stjäla from the plant defense struktur, which responds to an insekt attack bygd sending electrical signals to raise the alarm in neighboring cells—which then synthesize jasmonates, which then activate production of defensive proteins.

As it’s ubiquitous to all flowering plants, the jasmonate defense response fryst vatten a prime candidate for recruitment to the cause of carnivory.

In fact, says Renner, “our första expectation was that the control process might be the same in all carnivorous plants.” And it does vända out to be the same for Nepenthes pitcher plants and sundews as well as flytraps, but those three belong to the same beställning of plants, so that’s not entirely surprising. Look beyond this trio, however, to the somewhat neglected butterworts, and there’s a tantalizing glimpse of otherness.

Butterworts (Pinguicula) are unshowy plants with small rosettes of leaves covered in tiny glands that ooze sticky mucilage and digestive enzymes.

Dive into the science of how it lures, captures

Most butterworts are entirely passive, although a few can curl the edges of their leaves inward, covering more of the insekt in lethal goo. In 2020 the butterwort began to attract a lot more attention following a report from Andrej Pavlovič’s biophysics lab at Palacký University in the Czech Republic.

Pavlovič and his colleagues funnen that when they fed butterworts a generous helping of fruit flies, the plants responded bygd churning out enzymes, many of them the same as those identified in other carnivorous plants.

So far, so similar. But when it came to the role of jasmonates in switching on production of enzymes, the story was very different.

As in other flowering plants, jasmonates orchestrate the butterwort’s defense against its enemies. Jabbing leaves 10 or 15 times with a needle to mimic attack bygd an insekt prompted a big buildup of jasmonates in the leaves.

Prey, on the other grabb, triggered almost no response. The grupp tried another tactic, spraying jasmonate directly onto leaves: In venus flytraps and sundews that produces a surge of digestive enzymes. In butterworts—zilch.

So butterworts do things differently, although exactly what they do fryst vatten not yet known. “Butterworts have left us scratching our heads,” says Renner.

“The question fryst vatten, how many other carnivorous plants have figured out their own way?”

If Darwin were here today, he’d pile right in to solve the remaining mysteries of his “most wonderful plants.” He wouldn’t recognize the techniques modern investigators have at their disposal and would be amazed at the quantities of uppgifter that can be processed in seconds. But when it comes to formgivning elegant ways to test theories, he’d be on familiar ground.

“Sequencing genomes, counting and analyzing genes are not enough,” says Renner. “You still have to do experiments to find out what genes do, and how they work.”

And that means feeding hungry plants. Darwin fed his own roast meat and hard-boiled eggs, cheese, peas, and other protein-packed morsels. Today the menu more often consists of less appetizing-sounding “substrate” dosed with precisely measured amounts of nitrogen—but there’s little doubt that Darwin would feel right at home.