Environmental stresses lead to several mechanisms for adaptation in microorganisms with environment. A mutual beneficial relationship between endophyte fungi Neotyphodium and some grasses has been reported. It is demonstrated that the symbiotic relationship has improved the nutritional status and ecological adaptation of the plants. We hypothesized that part of the beneficial effects of the endophyte fungi on the plant nutritional status can be related to the enhanced catalytic functional diversity in the plant rhizosphere. Therefore the objective of this study was to identify the effects of endophyte infection on the activity of soil enzymes which contribute to the mineralization of essential nutrients in the rhizosphere of tall fescue( Festuca arundinacea Schreb). A greenhouse experiment was conducted with three soils, two grass genotypes and two endophyte(E+ and E-) status, with three replications. Furthermore, rhizosphere sampling was performed from a previously established farm experiment with similar genotype and endophyte treatments. Arginine ammonification and different soil enzyme activities were measured in both rhizospheric and bulk soils. Consistently, arginine ammonification and soil enzyme activities were significantly increased in E+ treatments. The sun ray integrative graphs showed that in both plant genotypes, endophyte infection can increase the overall microbial and enzymatic activities in the rhizosphere. This findings support the hypothesis suggesting that endophytes can increase the enzymatic functional diversity. Exceptionally, acid phosphatase did not follow the behavior of the other soil enzymes. The different response pattern of acid phosphatase can be attributed to its different origin. The enzyme is exclusively produced by the plant roots and apparently is not influenced by the endophyte infection. Significant and positive correlations were observed among arginine ammonification and activity of aryl sulfatas(r=0.77**), urease(r=0.58*), L-asparaginase(r=0.84L***), alkaline phosphatase(r=0.7**) and L-glutaminase(r=0.84***). Overall, we conclude that endophyte infection ha promoting effects on the microbial and biochemical activities in the rhizosphere and this may results in the enhanced nutritional and ecological status of the infected plants.
