Submitted by Teri_Windwalker t3_yuofps in askscience
To be specific: Do we know of a bacteria, virus or a less-obvious category of infection that can affect both an animal and a fungus? I imagine plants are too far removed to have overlap but the same question remains.
It can be assumed the resulting disorders from the infection would be far different but the concept doesn't seem as rare as a google search would imply.
djublonskopf t1_iwbklil wrote
The tobacco ringspot virus—an RNA virus infecting many different kinds of plants—has jumped from the plant kingdom to the animal kingdom, infecting the European honeybee. Various genera of rhabdoviruses are able to infect vertebrates, invertebrates, or plants, implying that both cross-kingdom and cross-phylum jumps have occurred within this virus family. Both groups are RNA viruses that—in their plant-infecting forms—use animals to spread from one plant to another...I imagine (but have no evidence) that this combination helped facilitate the jump between kingdoms.
There was also one documented case of plant-to-fungus virus transmission, where the cucumber ringspot virus was found to infect Rhizoctonia solani, a fungus that causes cucumber belly rot. The linked paper shows that the virus can actually move back and forth from plant to fungus to plant, making it a single multi-Kingdom virus.