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 knackmussiiMLR6 on growth promotion, photosynthetic responses, pigment contents and gene expression of the plant model Arabidopsis thaliana under NaCl stress. Methods and Results: The strain MLR6 was isolated from the rhizopshere of the halophyte Salsola tetrandra collected from a natural saline Algerian soil. Results showed the ability of MLR6 to induce plant growth‐promoting traits even under NaCl stress. The inoculation with MLR6 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. MLR6 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 NHX1,HKT1,SOS2 and SOS3 as well as SAG13 and PR1 was maintained in MLR6‐bacterized plant at a similar level of controls. Conclusions: The inoculation of A. thaliana with MLR6 improves plant growth and reduces damages caused by salt stress. Significance and Impact of the Study: The use of P. knackmussiiMLR6 appears as a promising strategy to improve the sustainable agriculture under saline conditions. [ABSTRACT FROM AUTHOR]