Off to botany: Carnivore mushrooms

Carnivorous plants are a popular and recurring theme of our fearsome popular culture.

At the Nevermore Academy, for example, that Goth Hogwarts from the streaming series "Wednesday", the botany teacher Mrs. Thornhill denies her lessons with special cultivated forms of the Venus flytrap and feeds them with fat earthworms.

In truth, however, the iconic sundew plants only snatch flies, ants or maybe a careless spider.

Ulf von Rauchhaupt

Editor in the “Science” section of the Frankfurter Allgemeine Sunday newspaper.

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In the case of

, on the other hand, worms are actually on the menu, albeit not from the annelid phylum but nematodes, among which

became the favorite animal of cell biologists in the 20th century and the first multicellular organism with a completely sequenced genome.

With a body length of no more than one millimeter,

is actually a microorganism in the laboratory, but biologically it is clearly an animal and is therefore taboo for vegetarians - but not for a carnivorous plant.

Only:

is not a plant.

He's a mushroom - in the folk sense, complete with style and hat, not one of those unsavory creatures that grow on toenails or turn ants into zombies.

In fact,

even belongs to the order Mushrooms and, with its light brown cap surface and snow-white lamellae, not only looks tasty, but it is.

In German it is officially called Austernseitling, in cookbooks it is sometimes also called “Veal Mushroom”, and it is easy to cultivate.

Something like that really eats worms?

In fact, only a few fungi have become accustomed to this in the course of evolution.

Of the almost 149,000 known types of fungi, only 150 improve their metabolism with nematodes - and just ten that form a fruiting body that laypeople can recognize as a fungus, including the oyster mushroom.

In the wild, it grows on decaying trees.

However, their tissue usually contains only little nitrogen, which is why the fungi obtain additional worm proteins.

A research group from Taiwan and Japan has now published how they do this in

published work found.

It was known that oyster mushrooms paralyze and kill the nematodes, which are found practically everywhere - a spade of earth contains a good million of these animals - with a highly effective toxin that they produce in their thread-like hyphae.

So far, however, it was unclear what kind of substance it is.

The authors of the study mentioned have now discovered that structures on the hyphae, so-called toxocysts, which look like small lollipops under the microscope, contain a comparatively simple chemical, 3-octanone from the ketone group.

For nematodes, this volatile compound is a nasty cytotoxin, as the researchers were able to show.

For humans, however, 3-octanone is not only non-toxic - at least in the amounts found in mushrooms - but also fragrant, for example, it is found in lavender, rosemary or nectarines.

Whether the substance also contributes to the aroma of fried oyster mushrooms has yet to be researched.

If this were the case, the 3-octanone would have proved to be a selection advantage in two ways: after cultivated mushrooms and shiitake mushrooms, oyster mushrooms now rank third in world human mushroom production.