i think i read about this a while ago - it seems it works but there is a drawback -
it was something along the lines of - with dmt in the sub the mushies were 3 times as potent, BUT the yeild was 1/3rd as big - so nothing is gained.

However there is a very interesting study that took place in Leipzig about 15 years ago. Jochen Gartz, a mushroom explorer whom I know quite well, has done some fascinating studies with Psilocybe species by raising them on solid media containing strange tryptamines that are alien to the mushroom. Apparently the enzymes that are responsible for the 4-hydroxy group of psilocin are indifferent to what it is they choose to 4-hydroxylate. He has taken things like DPT or DIPT and put them in the growth media and the fruiting bodies that came out contain 4-hydroxy-DPT or 4-hydroxy-DIPT instead of psilocin. In fact, he has a patent on the process. These active compounds are made by the mushroom so they really are natural and yet they never have been observed in nature. I'll give you even odds that if you put spores of a psilocybe species on cow droppings loaded with 5-MeO-DMT you would come out with mushrooms containing 4,5-HO-MeO-DMT. This way you avoid a 10 step synthesis by growing a psychoactive mushroom that contains no illegal drug.

Shulgin has explained that it could be possible to cultivate 4-HO-5-MeO-DMT in psilocybin mushrooms by adding 5-MeO-DMT to the growing substrate of the fungus. Though this method has never been explored with 5-MeO-DMT, it has been used successfully for changing DET into 4-HO-DET and 4-PO-DET, both of which had never before been found in nature.[2]

In the case of DET the mushrooms yielded only 4-HO-DET or 4-PO-DET respectively, instead of psilocin (4-HO-DMT) and psilocybin (4-PO-DMT), suggesting that the presence of the extraneous N-dialkylated tryptamines competed for the enzymes in the fungus mycelium that would normally produce psilocin. This method thus not only produced new chemical compounds that had never previously been made synthetically, but also rendered the fungus itself completely legal in many countries because of its absence of psilocin or psilocybin, although in countries with stricter drug analogue laws such as the USA or Australia the novel tryptamines produced would also be illegal.

Theoretically, this method would 4-hydroxylate and 4-phosphoryloxylate any tryptamine added to the substrate, opening the possibility of synthesizing as yet undiscovered tryptamines.

would make more sense to experiment using a substrate rich in tryptophan rather than adding dmt to it.

"Attempted Molecular Cloning of Enzymes from the Psilocybin Biosynthesis Pathway in Psilocybe tampanensis"
http://meltingpot.fortun.../gregory/1042/index.html

This diploma thesis gives many references on psilocybin biosynthesis, psilocybin detection, mushroom culturing, and molecular biology methods.