**1. Introduction**

Urbanization and industrialization lead to pollution that make water, air, and soil contaminated with high levels of heavy metals, organic and inorganic materials. These cause bioaccumulation and biomagnification in the ecosystem which in turn reflect in many health issues like colon cancer, heart diseases, liver, and kidney malfunction. These pollutions are solved by various methods such as removal, isolation, incineration, solidification –stabilization, vitrification, thermal treatment, solvent extraction, chemical oxidation, etc. To implement these methods several sophisticated techniques with skilled manpower are needed. They involve the transport of contaminated materials to treatment sites thus, adding ricks of secondary

contamination. *In situ* techniques that are eco-friendly and more economical can be used to minimize the problem. In this scenario, biotechnology offers a technique for phytoremediation [1].

Toxic substances that are released from various industrial effluents are loaded in the water bodies. When they enter into the surrounding agricultural fields during irrigation with heavy metals (Pb, Zn, Cd, Cu, Ni, Hg), metalloids (As, Sb), inorganic compounds, radioactive chemical elements (U, Cs, Sr), petroleum hydrocarbons (BTEX), pesticides and herbicides (atrazine, bentazone, chlorinated and nitroaromatic compounds), explosives (TNT, DNT), chlorinated solvents (TCE, PCE) and industrial organic wastes (PCPs, PAHs) pollute the land [2]. Phytoremediation can be considered as one of the effective phenomenons in regenerating soil fertility.

Phytoremediation is an efficient phenomenon in which the plant (trees, shrubs, grasses, and aquatic plants) and their associated microorganisms undergo metabolic pathway to remove, degrade or isolate toxic substances from the environment using effective enzymes including both intra and extracellular enzymes [2, 3]. The word "phytoremediation" is coined from the Greek word 'phyton', meaning 'plant', and Latin 'remedium', which means 'to remedy' or 'to correct'. As the meaning indicates heavy metals and the unusual compounds that are transported to cultivated land by the polluted water bodies are converted into nontoxic through phytoremediation. When they are bio-accumulated they are metabolized by the heavy-metal-resistant endophytes. Endophytes play a key role in the reduction and in the decrease of metal phytotoxicity and affect metal translocation which is accumulated in plants. The plant role in phytoremediation and the removal of accumulated toxicity in soil is as follows: modifying the physical and chemical properties of contaminated soils, releasing root exudates and thereby increasing organic carbon, improving aeration by releasing oxygen directly to the root zone, as well as increasing the porosity of the upper soil zones, intercepting and retarding the movement of chemicals, effecting co-metabolic microbial and plant enzymatic transformations of recalcitrant chemicals and decreasing vertical and lateral migration of pollutants to groundwater by extracting available water and reversing the hydraulic gradient [4, 5]. Strategies of photoremediaton and the efficacy of endophytes will enhance the understanding level paving way for further study.
