Wheat plant –Plant Growth Promoting Rhizobacteria (PGPR) interaction to alleviate the salt stress in vitro and in vivo

Abstract Posing a great potential of utilizing Plant Growth promoting Rhizobacteria (PGPR) as a promising alternative to alleviate salinity. Purpose: The aim of the current work is to illustrates the mechanistic basis of PGPRs-triggered salinity tolerance in wheat crops. Methods: Two experiments were conducted at Agricultural Research Center (ARC), 2021-2022, to evaluate the interaction between wheat plant var.Misr1 and two bacterial strains as PGPR namely, Azospirillum brasilense NO40 and Bacillus thuringiensis ( Bt ). One experiment were done in the Laboratory and the second was in the greenhouse. In the laboratory, the staining technique utilizing a spermosphere model was employed in order to detect the colonization efficiency of applied bacteria on wheat seedling roots under sterilized and saline conditions. Results: The date showed the red color of the wheat seedling roots that resulted from the reduction of 2,3,5 triphenyl tetrazolium chloride (TTC) to triphenyl formazan (TPF). Intensity of the red color increased as follow; wheat seedling roots inoculated with mixture of A. brasilense and Bt oculated with A. brasilense that inoculated with Bt . The interaction between wheat seedlings and the PGPR that were used in this work was followed up with transmission electron microscopy (TEM). The greenhouse experiment was conducted on saline soil from Sahl Elhosynia, north of Egypt, to evaluate the effect of these inoculation on growth, photosynthetic pigments and capacity, proline, dry weight of shoots and roots, some antioxidant and rhizosphere enzymatic activities. That data showed increase in all of that parameters in the wheat seedlings that inoculated with mixture of A, brasilense and Bt followed by that inoculated with A. brasilense alone, then by that inoculated with Bt . In conclusion: our bacterial strains that used in this work as inoculums for wheat plants under saline conditions could alleviate the salt stress in wheat saline soils. The mixture of the two strains A. brasilense and Bt gave the best results. Thus, we can apply this Mix in open field experiment to confirm this data.