Piriformospora indica: a new biological hardening tool for micropropagated plants.

Piriformospora indica is a novel plant growth promoting root endophyte. Regenerated plantlets of tobacco subjected to two different biological hardening techniques showed 88-94% survival when inoculated with P. indica as compared to 62% survival of uninoculated controls under similar conditions. The tendency of the plantlet to overcome the stress in terms of revival capacity was maximal in the case of P. indica as compared to the control. The fungus has the potential to render protection to the micropropagated plantlets and help them escape the 'transient transplant shock'.