Does the chemistry of fungal pigments demand the existence of photoactivated defense strategies in basidiomycetes? - Photochemical & Photobiological Sciences
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The well-known photosensitizers hypericin, harmane, and emodin are typical pigments of certain mushroom species—is this a coincidence or an indication towards a photoactivated defense mechanism in the phylum Basidiomycota? This perspective article explores this hypothesis by cross-linking the chemistry of fungal pigments with structural requirements from known photosensitizers and insights from photoactivated strategies in the kingdom Plantae. Thereby, light is shed on a yet unexplored playground dealing with ecological questions, photopharmaceutical opportunities, and biotechnological potentials.

Personally, I strongly believe it does!

I am particularly interested in the yellow stainer (Agaricus xanthoderma), which secretes a yellow compound when it is cut. This yellow compound is an azobenzene derivative (4,4′-dihydroxyazobenzene), and it is the only known natural azobenzene!

It is actually a very curious thing. Azobenzenes are very studied in the field of photochemistry because they are used as photoswitches, but no one has studied (as far as I can tell) why this mushroom makes an azobenzene… Phototoxicity, perhaps??