Alleviating Abiotic and Abiotic Stress, Enhancing Soil Fertility, and Growth of Forest Tree Species PGPR: A Review

The necessity for efficient mitigation techniques is highlighted by the worldwide loss in plant output caused by biotic and abiotic stressors. Promising bioinoculants known as Plant Growth-Promoting Rhizobacteria (PGPR) have been shown to provide improved nutritional availability, hormone regulation, and stress relief, among other advantages. Through several mechanisms such as phytohormone synthesis and ACC deaminase activity, they combat many environmental stressors such as pests, diseases, temperature variations, heavy metals, salt, and drought. Current research emphasizes the function of PGPR in a number of tree species, such as Quercus suber, Haloxylon ammodendron, and Acacia gerrardii. For example, inoculating Acacia gerrardii with Bacillus subtilis causes notable alterations in gene expression, indicating possible benefits in salinity and drought tolerance. Furthermore, in some nurseries, Quercus suber seedling quality is improved by a blend of bacterial inoculum and ECM fungus. Additionally, PGPR show effectiveness against heavy metal toxicity and heat stress. Sustainable plant growth depends on utilizing stress-resistant PGPR strains and maximizing microbial diversity. While breeding and genetic engineering provide long-term fixes, microbial inoculation offers a quick and affordable substitute. Moreover, PGPR promote environmental sustainability by improving soil fertility through processes including nitrogen fixation and phosphorus solubilization. In order to enhance plant development that is environmentally sustainable and optimize PGPR-mediated stress tolerance, it is essential to conduct multidisciplinary research and field investigations.