Characterization of Piriformospora indica culture filtrate

Sustainable crop production under biotic and abiotic stresses is a worldwide agricultural, eco-environmental, and economic problem that requires careful strategy, planning, research, and action to meet the needs of world’s growing population. One possible route to overcome these problems is to develop stress-tolerant crops through plant breeding. Such approaches have been successful for some plant species but not all the crops. Additionally, most of these approaches remain beyond the economic means of developing nations. An alternative route is to exploit mutualistic symbiosis between plants and arbuscular mycorrhizal fungi (AMF) to stimulate and promote plant growth. Piriformospora indica, belonging to the Sebacinales in Basidiomycota, is a newly described root endophyte (Varma (1998) Mycorrhiza manual. Springer, Heidelberg; Verma et al. Mycologia 90:895–909, 1998) with AMF-like characteristics, and it can be axenically grown unlike AMF that are obligate endosymbionts. Like fungal biomass, the culture filtrate also facilitates early seed germination and plant growth. Proper characterization of Piriformospora indica culture filtrate is an essential prerequisite to understand the underlying and still unknown mechanism(s) by which this fungus or its culture filtrate acts as a plant growth stimulator, promoter, and bioprotector. This chapter is devoted to develop a detailed protocol for the characterization and identification of P. indica culture filtrate.