Role of rhizospheric microbes in heavy metal uptake by plants

Due to industrialization, excessive use of pesticides and fertilizer and improper waste management practices cause heavy metal accumulation in both soil and water. Due to the nondegradable and persistent nature, heavy metals can be accumulated in soils for hundreds of years. They enter the bodies of plants and animals and thereby cause negative health impacts to the environment. Even though the soil heavy metal remediation is a must, it is not an easy task to achieve. Among many physical and chemical methods, phytoremediation plays an important role, due to its efficient and convenient nature. Rhizophere microbes play an important role in phytoremediation. Since, rhizosphere is the immediate vicinity of the root, the chemical and physical changes in that environment can easily effect heavy metal uptake by the plant. By siderophore production, acidification, releasing plant growth promoters, reducing the plant stress conditions and through redox changes rhizosphere enhances the phytoreomediation processes. However, plants can bioconcentrate (phytoextraction) and also bioimmobilize the toxic heavy metals through rhizospheric processes. This chapter summaries the role of rhizospheric organisms for facilitation of heavy metal uptake, the different mechanisms of enhancing the availability of heavy metals in the rhizosphere, the genetic diversity, and the microbial genera that involve in these processes.