Drought is the one of the most common and frequently co-occurring abiotic stresses constraining crop productivity worldwide. The endophytic fungus, Piriformospora indica was shown to enhance the growth and also tolerance to biotic and abiotic stresses. This work was intended to study the potential of P. indica in enhancing growth and elevating drought resistance in barley. Also the effect of fungus on proline, starch and soluble sugars content was investigated. The seedlings were inoculated with fungus and 2 weeks after inoculation were treated with three drought stress levels (Field capacity, 50% F.C. and 25% F.C.). Four weeks after inoculation, leaf samples were collected and starch and soluble sugars was extracted from leaves of inoculated and non-inoculated barley (cultivar Golden promise) plants. The physiological results showed that dry shoot and root weight were increased in inoculated plants compared with control plants under ambient and stress condition. Also, fungus affected soluble sugars and starch in inoculated plants and increased their content but the effect of fungus on proline wasn't significant. Based on our results, it seems that P. indica increased resistance to drought stress.
