Abstract: | Aims An experiment was performed to test how different fungal endophyte strains influenced tall fescue’s ability to access P from four P sources varying in solubility. MethodsNovel endophyte infected (AR542E+ or AR584E+), common toxic endophyte infected (CTE+), or endophyte-free (E-) tall fescues were grown for 90 days in acidic soils amended with 30 mg kg?1 P of potassium dihydrogen phosphate (KH2PO4), iron phosphate (FePO4), aluminum phosphate (AlPO4), or tricalcium phosphate ((Ca3(PO4)2), respectively. ResultsPhosphorus form strongly influenced plant biomass, P acquisition, agronomic P use efficiency, microbial communities, P fractions. P uptake and vegetative biomass were similar for plants grown with AlPO4, Ca3(PO4)2, and KH2PO4 but greater than in control and FePO4 soils. Infection with AR542E+ resulted in significantly less shoot biomass than CTE+ and E- varieties; there was no influence of endophyte on root biomass. The biomarker for arbuscular mycorrhizal fungi (AM fungi, 16:1ω5c) was selected as an effective predictor of variations in P uptake and tall fescue biomass. Potential acid phosphatase activity was strongly influenced by endophyte x P form interaction. ConclusionsEndophyte infection in tall fescue significantly affected the NaOH-extractable inorganic P fraction, but had little detectable influence on soil microbial community structure, root biomass, or P uptake. |