Bioremediation of Polluted Soil by Using Plant Growth–Promoting Rhizobacteria

Abstract

Soil pollution generally causes huge losses in the world’s agricultural output, and therefore, soil pollution control is essential in agriculture crop production system. For soil pollution management, we usually reduce the use of chemical fertilizers, manures, and pesticide, reuse the domestic waste product materials such as glass containers, plastic bags, paper, and cloth, and recycle the materials such as some kinds of plastics and glass cane, but their indiscriminate use causes environmental problems and human health hazards. Moreover, the continuous use of those products without safe disposal leads to soil pollution. Thus, bioremediation of soil pollution is an alternate eco-friendly method for soil pollution management, in which plant growth–promoting rhizobacteria are used in alleviating the contaminated soil. Many rhizosphere microorganisms including Azotobacter spp., Pseudomonas aeruginosa, Glomus spp., Acaulospora spp., Scutellospora spp., Streptomyces spp., Klebsiella spp., Lysobacter spp., Rhizobium leguminosarum, Burkholderia spp., Diaphorobacter nitroreducens, Planomicrobium chinense, Promicromonospora spp., Mesorhizobium spp., Psychrobacillus psychrodurans, Pantoea spp., Arthrobacter spp., and Variovorax spp. have been found as plant growth–promoting rhizobacteria. These PGPR have been found to bioremediate the polluted soil by using various types of mechanisms such as through siderophore production, phosphate solubilization, biological nitrogen fixation, production of 1-aminocyclopropane-1-carboxylate deaminase (ACC), quorum sensing, signal interference and phytohormone production, exhibiting antifungal activity, production of volatile organic compounds, and induction of systemic resistance, promoting beneficial plant-–microbe symbioses. Thus, there are immense possibilities for identifying other growth-promoting rhizobacteria that could help in bioremediation of polluted soil as well as promote sustainable agriculture.