Potential of plant growth-promoting rhizobacteria-plant interactions in mitigating salt stress for sustainable agriculture: A review

Soil salinization affecting different crops is one of the serious threats to global food security. Soil salinity affects 20% and 33% of the total cultivated and irrigated agricultural lands, respectively, and has been reported to caused a global crop production loss of 27.3 billion USD. The conventional approaches, such as using salt-tolerant varieties, saline soil scrapping, flushing, leaching, and adding supplements (e.g., gypsum and lime), often fail to alleviate stress. In this context, developing diverse arrays of microbes enhancing crop productivity under saline soil conditions without harming soil health is necessary. Various advanced omics approaches have enabled gaining new insights into the structure and metabolic functions of plant-associated beneficial microbes. Various genera of salt-tolerating rhizobacteria ameliorating biotic and abiotic stresses have been isolated from different legumes, cereals, vegetables, and oil seeds under extreme alkaline and saline soil conditions. Rapid progress in rhizosphere microbiome research has revived the belief that plants may be more benefited from their association with interacting diverse microbial communities as compared with individual members in a community. In the last decade, several salt-tolerating plant growth-promoting rhizobacteria (PGPR) that improve crop production under salt stress have been exploited for the reclamation of saline agrosystems. This review highlights that the interaction of salt-tolerating microbes with plants improves crop productivity under salinity stress along with potential salt tolerance mechanisms involved and will open new avenues for capitalizing on cultivable diverse microbial communities to strengthen plant salt tolerance and, thus, to refine agricultural practices and production under saline conditions.