Pseudomonas knackmussii MLR6, a rhizospheric strain isolated from halophyte, enhances salt tolerance in Arabidopsis thaliana

Aims The study aimed for evaluate the efficacy of Pseudomonas knackmussii MLR 6 on growth promotion, photosynthetic responses, pigment contents and gene expression of the plant model Arabidopsis thaliana under NaCl stress. Methods and Results The strain MLR 6 was isolated from the rhizopshere of the halophyte Salsola tetrandra collected from a natural saline Algerian soil. Results showed the ability of MLR 6 to induce plant growth‐promoting traits even under NaCl stress. The inoculation with MLR 6 improved the stomatal conductance, the transpiration rate, the total chlorophyll and carotenoid contents under salt stress. It conferred also an increase in fresh/dry weight as well as plant height. MLR 6 inoculation further provided a positive effect on cell membrane stability by reducing the electrolyte leakage and priming the ROS accumulation after the salt exposition. Additionally, the expression of NHX 1 , HKT 1 , SOS 2 and SOS 3 as well as SAG 13 and PR 1 was maintained in MLR 6‐bacterized plant at a similar level of controls. Conclusions The inoculation of A. thaliana with MLR 6 improves plant growth and reduces damages caused by salt stress. Significance and Impact of the Study The use of P. knackmussii MLR 6 appears as a promising strategy to improve the sustainable agriculture under saline conditions.