Halotolerant plant growth-promoting rhizobacteria improve soil fertility and plant salinity tolerance for sustainable agriculture—A review

Due to climate change, expansion of salt-affected arable lands has emerged as a major threat to global food security and agricultural sustainability. Conventional crop breeding programs have proven insufficient for mitigating the risks of salt stress in soil and crop productivity. Research on improving soil health and crop tolerance to boost yield performance under salt stress by plant-associated microbiomes has gained considerable attention over the past few decades. In addition to the rehabilitation of salt-degraded soils, halotolerant plant growth-promoting rhizobacteria (HT-PGPR) are effective in stimulating growth, improving nutritional values and yields, and increasing tolerance/resistance to abiotic/biotic stress conditions of plants. To alleviate salinity stress, HT-PGPR employ a wide range of mechanisms, including production of secondary metabolites and siderophores, synthesis of phytohormones and enzymes, maintenance of ion homeostasis, and increasing nutrient availability in crop plants. Because our goal is to continuously improve our understanding of HT-PGPR and their impact on agriculture, the current review addresses the challenges associated with salinity, and updates the scientific community with effective solutions (e.g., HT-PGPR) for sustainable agriculture and farming practices.