Over 95% of plants make mycorrhizal associations and many are actually completely dependent on mycorrhizae. Most plant roots aren't actually made for "sucking u

Over 95% of plants make mycorrhizal associations and many are actually completely dependent on mycorrhizae. Most plant roots aren't actually made for "sucking up nutrients" but rather for trading sugars for minerals and other nutrients with mycorrhizal fungi. It's not at all accurate to label these "parasites" in my opinion. Plants that have these associations produce larger fruit, are more resistant to pests, can withstand both droughts AND frosts better, and are generally significantly healthier. These networks transfer more than just nutrients. It's also a communication network that allows plants across species to warn each other of pests. Recent research shows that even RNA might be being transmitted through mycorrhizal networks and we know that mother trees are able to identify their offspring and send specific nutrients to them and possibly even some sort of chemical, acquired memories. HGT is not at all unique to mycorrhizal fungi. One interesting example is the dodder plant which is an obligate "parasite" that can affect many different species of plants. A very large portion of its DNA is now plant genes from various species its parasitized. Though it's not clear if these genes are used. It also turns out that dodder plants too can act as above-ground communication networks; allowing plants to warn each other of pests and other threats. But more and more evidence is emerging that HGT is much more common than we would predict in even mammals and fish. The gene to produce a crucial antifreeze protein in smelt came from herrings for example: https://www.quantamagazine.org/dna-jumps-between-animal-species-no-one-knows-how-often-20210609/ https://www.quantamagazine.org/dna-jumps-between-animal-spec... > I'd bet you could find the absolute right frequency based on plant species There's two major types of mycorrhizal fungi: arbuscular and ectomycorrhizal (there's also endo- but these, by definition, aren't soil fungi). Arbuscular fungi seem to have very low host specificity and are kinda "generalists". One species found in Australia was found to improve crop yields amongst almost every single crop they tested it on. The complex handshake that goes on between plant roots and mycorrhizal fungi seems to be very ancient (fungi made it on to the land first and plants likely wouldn't have survived without their help). I would guess that most plant species evolved to support this ancient language and there isn't enough variation to differentiate anything at the species level. Perhaps you'd have more luck with ectomycorrhizal fungi, but even then I would assume the frequency is much more likely to be associated with fungi species than plant species.