Unravelling the role of plant growth promoting rhizobacteria in boosting plant growth and phytoremediation of heavy metals

Soil and water contamination by heavy metal (HM) toxicants, resulting from geological and anthropogenic activities, poses a significant threat to the global food security because of their non-biodegradable nature. Conventional methods, while effective, incur high operational costs and have a detrimental impact on soil properties, rendering them unsustainable. Consequently, phytoremediation, employing hyperaccumulator plants to extract HM toxicants, has emerged as a promising alternative. However, the toxic nature of HM creates an inhospitable environment for plant growth, necessitating alternative strategies for effective remediation. This review critically evaluates the role of plant growth promoting rhizobacteria (PGPR) in enhancing both plant growth and the efficacy of phytoremediation. PGPR facilitate plant growth through mechanisms such as nitrogen fixation, phosphorus solubilization, hormone production, and nutrient uptake. Moreover, they enhance metal tolerance by regulating metal transporter, tolerant, and chelator genes. This analysis underscores PGPR as a sustainable and eco-friendly solution for contaminated soil remediation while promoting plant growth. Additionally, it emphasizes the imperative for future research to elucidate the intricate molecular mechanisms underlying PGPR-induced phytoremediation.