Effect of Neotyphodium endophyte symbiosis on growth, Nickel uptake and photosynthetic pigments in two genotypes of tall fescue

Soil pollution with heavy metals is an important environmental problem which affects human and food health. Neotyphodium endophytes are a group of fungi which spend their entire life cycle within the aerial portion of many grass species without any symptoms, and increase host tolerance to biotic and abiotic stresses. In this study, two genotypes of tall fescue (75 B and 75 C) in two types (infected (E+) and non-infected (E-) by endophyte) were cultivated in a Ni contaminated soil at 0, 30, 90 and 180 mg Ni per kg with 3 replicates. After 2 months, Ni uptake of the root and shoot as well as chlorophyll and carotenoid content of the shoot were measured. Growth parameters including root and shoot wet weight and root to shoot weight ratio of plants were also measured at the end of the experiment. The results showed that endophytic fungi caused an increase in chlorophyll contents of the shoots in the both genotypes and an increase in Ni uptake only in genotype 75 B. Results also demonstrated that endophyte infection led to improvement in the growth and Ni tolerance within genotype 75 B of tall fescue under Ni stress. But in the genotype 75 C, in contrast, the E- plants showed more tolerance to Ni stress compared to E+ plants. It revealed that how the effects of endophyte infection in Festuca plants as the host were dependent on the host genotype.