Leaf endophyte Neotyphodium coenophialum modifies mineral uptake in tall fescue

Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon and Hanlin, a fungal endophyte found primarily in shoots of tall fescue (Festuca arundi nacea Shreb.), can modify rhizosphere activity in response to phosphorus (P ) deficiency. In a controlled environment experiment, two cloned tall fescu e genotypes (DN2 and DN4) free (E-) and infected (E+) with their naturally occurring endophyte strains were grown in nutrient solutions at low P (3.1 ppm) or high P (31 ppm) concentrations for 21 d. Endophyte infection increa sed root dry matter (DM) of DN4 by 21% but did not affect root DM of DN2. U nder P deficiency, shoot and total DM were not affected by endophyte but re lative growth rate was greater in E+ than E- plants. In high P nutrient sol ution, E+ plants produced 13% less (DN2) or 29% more (DN4) shoot DM than E- plants. Endophyte affected mineral concentrations in roots more than in sh oots. Regardless of P concentration in nutrient solution, E+ DN2 accumulate d more P, Ca, Zn and Cu but less K in roots than E- plants. When grown in h igh P nutrient solution, concentrations of Fe and B in roots of E+ DN2 plan ts were reduced compared with those of E- plants. Concentrations of P, Ca a nd Cu in roots of DN4 were less, but K was greater in E+ than E- plants. In shoots, E+ DN2 had greater concentrations of Fe and Cu than E- DN2, regard less of P concentration in nutrient solution. Genotype DN4 responded to end ophyte infection by reducing B concentration in shoots. Nutrient uptake rat es were affected by endophyte infection in plants grown in low P nutrient s olution. A greater uptake rate of most nutrients and their transport to sho ots was observed in DN2, but responses of DN4 were not consistent. Results suggest that endophyte may elicit different modes of tall fescue adaptation to P deficiency.