Use of Piriformospora indica as Potential Biological Hardening Agent for Endangered Micropropagated Picrorhiza kurroa Royel ex Benth

The rich plant biodiversity of Himalayan region is vanishing at an alarming rate due to urbanization and indiscriminate collection of important plants at a large scale from the wild for trade. Overexploitation of Picrorhiza kurroa, an alpine Himalayan medicinal plant for extraction of its active compounds has led to the reduction of its natural population. In vitro regeneration offers a noteworthy solution for the propagation of endangered medicinal plants. Successful acclimatization of in vitro plants with fungal endophyte Piriformospora indica reduces the mortality rate of in vitro plantlets due to transplantation shock. Root colonization with P. indica renders growth promotion and better adaptation of a wide range of plants. Present study focuses on the use of P. indica as a biological hardening agent for increasing the percentage survival of in vitro shoots. Survival of fungus treated biohardened in vitro plants was increased by 1.3 folds. Root number in 4 weeks old P. indica treated biohardened in vitro plants enhanced by 1.25 fold and facilitated its establishment under greenhouse conditions.