Can fungi absorb chemicals from its host?

by Sage
(Vancouver, BC)

QUESTION:

I have been finding and foraging beautiful shelves of chicken of the woods from trees in my neighbourhood. They LOVE to grow on a specific cherry plum tree, which I have identified as a 'Pissard Plum' (Prunus cerasifera).

As I have learned, all parts of Prunus trees contain cyanogenic glycosides: cyanide molecules attached to sugar molecules. Are the mushrooms still safe to eat?

I can't find any information online, but I am wondering if they can absorb the cyanide because they are attached to the trees.

Please let me know!


ANSWER:

Sage, hi

Great question! This is a concern that has been raised by foragers and mycologists alike.

It seems like more research needs to be done, as there are conflicting opinions on this.

Some mycologists say there’s no risk or problem.

They say chicken of the woods mushrooms growing on your cherry plum tree are most likely safe to eat, despite the tree containing cyanogenic glycosides.

Why? Because Chicken of the Woods mushrooms are decomposers that feed on dead and dying wood. They do not directly absorb or accumulate toxins from the living tree. Also, the cyanogenic glycosides in cherry plum trees are primarily concentrated in the seeds/pits. The amount in the wood is likely very low.

Other experts are more cautious.

They talk about how fungi can absorb various compounds from their host substrate, including potentially harmful ones. They say that fungi growing on toxic trees might absorb toxins, which could make the mushrooms unsafe to eat.

What should you do?

For as long as there's no definitive research confirming the absorption of cyanogenic glycosides by these mushrooms, the potential health risks from consuming cyanide-contaminated mushrooms make it not worth the risk.

In your shoes, absent a definitive answer, I’d leave those “chickens” where they are.

I hope this answer doesn’t disappoint!

Best wishes,

Nick