PGPR consortia enhance growth and yield in barley cultivars subjected to severe drought stress and subsequent recovery

With the continuous increase of land areas affected by drought due to climate change, barley, a cereal globally consumed by the human population, faces significant challenges from drought stress. The current study aims to showcase the effectiveness of two consortia based on Plant Growth-Promoting Rhizobacteria (PGPR) strains in promoting plant growth and recovery in post-drought conditions of drought-sensitive and tolerant barley cultivars. Inoculations with Consortium 1 and 2 enhance barley plant tolerance to drought stress by impacting relative water content, SPAD index, and Fv/Fm while decreasing electrolyte leakage. Similarly, in biochemical traits, both consortia influence proline, total soluble sugars, H₂O₂, and MDA contents, as well as catalase and ascorbate peroxidase activities. Regarding agro-morphological traits, the consortia contribute to increased root and vegetative shoot dry weights, along with a positive effect on grain yield and thousand-grain weight, achieving values equivalent to unstressed plants. The highest important effect in recovered plants was recorded in the case of the tolerant cultivar inoculated with Consortium 1, in most of the traits studied, there was no significant difference recorded between unstressed and recovered barley plants. Consortium 1 and Consortium 2 improve the tolerance of both sensitive and tolerant barley cultivars against drought, aiding recovered plants in regaining physiological status equivalent to unstressed ones.