Mechanism of Heavy Metal ATPase (HMA2, HMA3 and HMA4) Genes

Heavy metals are the most important pollutants that are non-biodegradable and increasingly accumulate in the environment. Phytoremediation can be defined as the use of plants for the extraction, immobilization, containment, or degradation of contaminants. It provides an ecologically, environmentally sound and safe method for restoration and remediation of contaminated land. Plant species vary in their capacity of hyper-accumulation of heavy metals. The chapter reviews the current findings on the molecular mechanism involved in heavy metals tolerance, which is a valuable tool for phytoremediation. The heavy metal tolerance genes help in the hyper-accumulation trait of a plant. Heavy metal transporter ATPases (HMAs) genes help in the refluxing of heavy metal ions from the cytosol, either into the apoplast, the vacuole, or other organelles, which help in the hyperaccumulation of metal. Understanding the signaling mechanism of transporter genes will be an important tool to understand the genetics of hyperaccumulation.

Phytormediation Efficiency Increased by Using Plant Growth Promoting Bacteria (PGPB) and Chelates

In this chapter, the authors give information about the plant-growth-promoting bacteria and chelating agents removing high number of contaminants with the help of phytoremdiation technology. To the best of the authors' knowledge, this is the first chapter about heavy metal contamination in groundwater and soil removing by microbes and chelates.

Effect of Plant Growth Promoting Bacteria (PGPB) on Phytoremdiation Technology

In this chapter, the authors describe how plant-growth-promoting bacteria is helpful for removing soil contaminants and also increasing the efficiency of phytoremediation technology. The plant growth bacteria seem almost good for removal of soil contaminants, and they can adsorb and accumulate metals in their cells and are being used in microbial leaching and also as agents of cleaning the environment.

Newer Approaches in Phytoremediation

The heavy metal pollution problem is all over the world. Plant-growth-promoting bacteria (PGPB) has transformed heavy metals present in the soil, which removes and minimizes their toxic effects. This chapter highlights the role of plant-growth-promoting bacteria, chelating agents, and nanoparticles for remediation of heavy metals; their mechanism of action; and their applications approach of hyperaccumulation. Therefore, this chapter focuses on the mechanisms by which microorganisms, chelating agents, and nanoparticles can mobilize or immobilize metals in soils and the nano-phytoremediation strategies are addressed for the improvement of phytoextraction as an innovative process for enhancement of heavy metals removal from soil.

Fluoride Contaminated Groundwater

In this chapter, the authors explore Fluoride (F) in groundwater as a major issue of water pollution. Geo-statistical analysis of groundwater quality in Newai Tehsil (India) has been done in order to identify the possible spatial distribution of water quality parameters and to assess the spatial dependence of water properties with the help of principal component analysis (PCA) structure. Two types of maps (spatial map and principal component map) of groundwater quality have been developed. A field experiment was conducted to investigate the effect of different Fluoride (F) concentration combined with Pseudomonas fluorescens (P.F) on Prosopis juliflora plant. The field design was used as completely randomized block design with three replicates. The study revealed that parameters were found to be positively and highly correlated with principal component. Low and high values (with their acceptable limit) have also been displayed over each spatial map. Plants treated with P. fluorescens showed the highest F uptake in root, shoot, and leaves tissues were 33.14, 19.41, and 15.15 mg kg-1 after 120 days, respectively. Both total bioaccumulation factor (BF) and translocation factor (TF) were obtained above one (i.e., 1.06 and 1.04). This confirmed the high accumulation and translocation of F in plant tissues. The F uptake efficiency of plant was enhanced to 67.7%, and plant biomass was increased to 57.03%. The present study will be beneficial for researchers working towards further improvement of F phytoremediation technology.

Non-Metal Pollution (Fluoride)

In this chapter, the authors describe Fluoride contamination spread in the environment. Fluoride in groundwater is a serious problem. Groundwater is the most valuable fresh water used for drinking purposes in different areas. Irrigation is one primordial sector in India where one-third of land surface falls under arid and semi-arid climate, and rainfall is seasonal and erratic. Semi-arid climate prevailing in Tonk district necessitates the characterization of groundwater quality for optimizing its use in irrigation as well as in domestic consumption. The majority of underground water contains a high concentration of salts, and their continuous use adversely affects soil, animal, and plant health, and thereby crop production. The plant-based phytoremediation approach to improve the quality of water and soil has become an area of importance to study regarding Fluoride.

Role of Phytochelatines (PCs) and Metallothionines (MTs) Genes Approaches in Plant Signalling

In this chapter, the authors reported that phytochelatines (PCs) and metallothionies (MTs) are actively involved in metal binding and detoxification as observed more in hyperaccumulation plant species. Also, most reports have explained single metal/metalloid detoxification via PCs and MTs; hence, it remains to be seen how plants use these metal ligands at the time of multiple metal stress and generate at the time of defence system against heavy metal stress condition.

Introduction to Phytoremediation

In this chapter, the authors describe phytoremediation technology, which is helpful for remediation of contaminated soil and groundwater. This information can be used for water and soil purification and may contribute to successful transfer of phytotechnologies to the agricultural or commercial sectors.

Role of Plant Growth Promoting Rhizosphere (PGPR) on Molecular Mechanisms Transporters Under Heavy Metal Stress

In this chapter, the authors discuss the molecular mechanisms transporters used for the removal of heavy metals contaminants from soil and water. The bioremediation method used for soil remediation render the land useless as a medium for plant growth as they also remove other contaminants that harm microbes and maintaining soil fertility with the help generating heat shok protein and metallothiones and also molecular transporters.

Heavy Metal Stress Mechanism by Signaling Cascades in Plants

This chapter highlights the role of cascade for remediation of heavy metals, their mechanism of action, and their applications approach of hyperaccumulation. Further, it also highlights the role of uptake and detoxification of metals by cellular mechanisms that facilitate the bioremediation of heavy metals from contaminated areas.