Mitigation of NaCl Stress in Wheat by Rhizosphere Engineering Using Salt Habitat Adapted PGPR Halotolerant Bacteria

Abstract

There is a great interest in mitigating soil salinity that limits plant growth and productivity. In this study, eighty-nine strains were isolated from the rhizosphere and endosphere of two halophyte species (Suaeda mollis and Salsola tetrandra) collected from three chotts in Algeria. They were screened for diverse plant growth-promoting traits, antifungal activity and tolerance to different physico-chemical conditions (pH, PEG, and NaCl) to evaluate their efficiency in mitigating salt stress and enhancing the growth of Arabidopsis thaliana and durum wheat under NaCl–stress conditions. Three bacterial strains BR5, OR15, and RB13 were finally selected and identified as Bacillus atropheus. The Bacterial strains (separately and combined) were then used for inoculating Arabidopsis thaliana and durum wheat during the seed germination stage under NaCl stress conditions. Results indicated that inoculation of both plant spp. with the bacterial strains separately or combined considerably improved the growth parameters. Three soils with different salinity levels (S1 = 0.48, S2 = 3.81, and S3 = 2.80 mS/cm) were used to investigate the effects of selected strains (BR5, OR15, and RB13; separately and combined) on several growth parameters of wheat plants. The inoculation (notably the multi-strain consortium) proved a better approach to increase the chlorophyll and carotenoid contents as compared to control plants. However, proline content, lipid peroxidation, and activities of antioxidant enzymes decreased after inoculation with the plant growth-promoting rhizobacteria (PGPR) that can attenuate the adverse effects of salt stress by reducing the reactive oxygen species (ROS) production. These results indicated that under saline soil conditions, halotolerant PGPR strains are promising candidates as biofertilizers under salt stress conditions.

Morphological, Biochemical, and Metabolomic Strategies of the Date Palm (Phoenix dactylifera L., cv. Deglet Nour) Roots Response to Salt Stress

“…Soil salinization is becoming a major problem in multiple regions around the world. It is affected by numerous factors, including climate changes and uncontrolled anthropogenic activities by the continuously increasing human population [1,2]. The extent of land salinization is determined by measuring the level of pH, certain ions' (Na + , Ca 2+ , SO 4 2− , K + , SO 4 2− , Cl − , and Mg 2+ ) accumulation, and electrical conductivity (>4 dSm −1 ) [3,4].…”

Effects of Compost Amendment on Glycophyte and Halophyte Crops Grown on Saline Soils: Isolation and Characterization of Rhizobacteria with Plant Growth Promoting Features and High Salt Resistance

“…Their identification, isolation, molecular classification and possessing relevant PGP features are essential for moving towards an agriculture more respectful of agroecosystems and consequently of human and animal health [52]. As stated above, salinization is one the main problem afflicting agricultural soils, however PGPRs can be of great help in reducing the impact of soil salinization and, at the same time, improving crop productivity and health [53,54]. The bacterial strains, we isolated and taxonomically classified in this research work, showed tolerance to very high NaCl concentrations, but also several PGP features, demonstrating, once more, that compost amendment of soil not only increases its fertility, but it is also a valuable source of rhizosphere bacteria able to promote health, resilience and plant productivity.…”

Setting a Plausible Route for Saline Soil-Based Crop Cultivations by Application of Beneficial Halophyte-Associated Bacteria: A Review

“…As shown in Table 3 , the isolated IAA-producing microbes significantly enhanced plant growth in biomass under the simulated saline condition in terms of shoot length and weight (fresh and dry), emphasizing root length and weight (fresh and dry), and germination rates of salt-sensitive crop seeds. Furthermore, the selected microbes will have a slight improvement to no significant effects on non-stressed control plants [ 63 , 104 , 114 , 115 ].…”