Beneficial root endophyte Piriformospora indica reduces plant sodium uptake and enhances cell hydraulic conductivity and salt tolerance of maize seedlings

Background and aimsFungal root endophyte Piriformospora indica has been implicated in enhancing plant tolerance to salt stress. This study aimed to understand the role of root cell hydraulic conductivity in enhancing salt tolerance of maize plants by this fungal endophyte.MethodsMaize seedlings inoculated with P. indica were compared with non-inoculated control plants following exposure to 0, 60, and 120 mM NaCl for 24 days and their growth and physiological parameters including root cell hydraulic conductivity examined.ResultsThe shoot dry weights were significantly higher in P. indica- inoculated seedlings compared with non-inoculated plants regardless of the NaCl concentration treatment. Compared to 60 mM NaCl, the 120 mM NaCl treatment further decreased shoot dry weights or shoot to root dry weight ratios in the non-inoculated seedlings, but not in plants inoculated with P. indica . The 120 mM NaCl treatment reduced the root cell hydraulic conductivity, net photosynthetic rates, transpiration rates, and leaf chlorophyll in the non-inoculated plants compared to the inoculated plants. Following the 120 mM Nacl treatment, P. indica- inoculated seedlings had lower root and shoot Na concentrations compared with the non-inoculated seedlings. Both 60 mM and 120 mM NaCl treatments affected the final seed yield less in the inoculated compared with the non-inoculated plants.ConclusionsThe results demonstrate that the enhancement of salt tolerance in maize plants by P. indica involves reductions in root and shoot Na uptake and maintenance of the transmembrane root water transport which helped alleviate the effects of NaCl on gas exchange and growth.