The article where Piriformospora indica was originally described is available at Cyberliber (http://www.cybertruffle.org.uk/cyberliber/). Search for Mycologia 90:896-903.
The global biodiversity information facility (www.gbif.org) only mentions one locality (India) but apparently isolates are available at the CBS-KNAW Fungal Biodiversity Centre in the Netherlands and at the Jena Microbial Resource Collection (JMRC), Leibniz Institute for Natural Product Research and Infection Biology, Germany.