Effect of seed priming with selenium nanoparticles and plant growth promoting rhizobacteria on improving Quinoa seedling growth under salinity stress

Soil and water salinity are the most important problems that limit crop production, especially in the arid and semi-arid regions. This study was conducted to investigate the effect of growth-promoting bacteria and selenium nanoparticle pretreatment on increasing the tolerance of the Chenopodium quinoa plant to salinity. A factorial experiment was conducted in a completely randomized design with three replications. Experimental treatments consisted of selenium nanoparticles at a concentration of 1 mg L-1, Bacillus cereus (BW) and Pseudomonas fluorescens (Ps) and three different levels of saline solution with concentrations of 0, 200 and 400 mM sodium chloride. The results showed that quinoa seeds soaking in selenium nanoparticle solution and PGPRs by increasing photosynthetic pigments (up to about 96% in Se+BW pretreated plants), compatible solutes (approximately 65% increase in prolin content in Se+Bw treatment), reducing oxidative stress (increased the activity of some antioxidant enzyme in about 100%), protecting the cell membrane (decreased the MDA up to 32%) and reducing sodium uptake (in about 23% in Se+Ps pretreated plant) improve plant growth and increase the quinoa resistance at salinity conditions. The results of this study showed that Se, although not essential element for plants, can improve growth and morphological parameters of the plant under salinity stress at low concentrations and it has more effects in the presence of PGPRs. So, it is suggested that these two biostimulators can be used together for protecting plants from salinity damaged and this strategy could be applied for sustainable agriculture. In addition, since most of the positive functions of these bacteria were not affected by salinity stress, so this type of bacteria can be used with selenium in saline soils.