Selenium uptake and accumulation in winter wheat as affected by level of phosphate application and arbuscular mycorrhizal fungi

Selenium (Se) is an advantageous element to crops. However, the influence of arbuscular mycorrhizal fungi (AMF), phosphate (P) and selenite in soil on Se uptake by winter wheat remain elusive. Pot trials were carried out including seven levels of P (0, 12.5, 25, 50, 100, 200 or 400 mg kg−1) and non-mycorrhizal inoculation (NM), inoculation of Funneliformis mosseae (F.m) or Glomus versiforme (G.v). The present results found that grain phosphorus concentration increased with increase of P level from 0 to 100 mg kg−1 and then tended to plateau, while grain Se concentration decreased with the level of P from 0 to 400 mg kg−1. Based on mathematical modeling, inoculation of F.m or G.v dramatically improved grain Se concentration by 16.90% or 12.53% under the lower level of P (48.76 mg kg−1). Furthermore, partial least squares path modeling (PLS-PM) identified that both up-regulated of the expression of AMF-inducible phosphate transporter and improved Se bioavailability in rhizosphere soil contributed to enhancing plant Se concentration under P levels ≤ 100 mg kg−1. The present study demonstrated that AMF combined with 48.76 mg kg−1 P applied in soil can not only achieve high grain yield, but also fully exploit the biological potential of Se uptake in wheat.