Environmental Phytoremediation: Plants and Microorganisms at Work

Phytoremediation is the use of plants to reclaim polluted environment (soils and waters) through mechanisms of extraction, sequestration and detoxification of both organic and inorganic compounds that may be toxic for living organisms. Phytoremediation is a generic term that includes a range of applications, which are grouped as phytovolatilization, phytostimulation, phytostabilization, phyto- and rhizo-degradation, phytoextraction and rhizofiltration. These processes take advantage of the interactions between plants and microorganisms. Rhizospheric bacteria and fungi engage a variety of metabolic activities that influence pollutant chemistry, bioavailability and mobility and promote plant fitness and growth. Physiological changes in plants are also triggered by endophytic microorganisms which influence the plant water and metal uptake and, by conducting stepwise transformation of organic contaminants improve the phytoremediation efficiency. On the other hand, plant photosynthesis provides organic compounds that can be exploited as carbon sources for microbial population. In this view, microbial-assisted phytoremediation is emerging as a novel approach, which may find application in remediation of both organic and metallic contaminants. Moreover, it is worth noting that transgenic plants and/or microorganisms may find application in novel phytoremediation approaches, whose utilization may result in enhanced plant growth, detoxification properties for organic pollutants or accumulation capacity for inorganic contaminants. Genetic information that meliorate phytoremediation technology may derive from both microbial and plant genomes. Researchers have genetically engineered the bacteria that find application in phytoremediation, both enhancing their detoxification/accumulation ability and their synergistic capacity towards plants. Finally, microbial-assisted phytoremediation has been for long time verified under laboratory conditions, but its application in field, to remediate both organic compounds and heavy metals, is still under evaluation. Phytoremediation has been considered as cost-effective and environmentally friendly in respect to traditional chemical-physical based techniques. Despite this, many are the challenges that face large-scale in vivo application, first of all the strategy and design, which have to be specifically tailored to the environmental conditions of each polluted site, such as soil composition, temperature range, type, concentrations of contaminants and its bioavailability. Release of volatile pollutant compounds from groundwater and soil to the atmosphere is a further complication to phytoremediation feasibility. Moreover, plant and microbial transgenic manipulation usually lack of public acceptance and trust, which should be overcome by the collaboration of researchers and public administrators to support regulatory and policy decisions and ensure environmental strategies and regulation of phytoremediation.
This Research Topic will highlight novel information acquired in the field of microbial-assisted phytoremediation, considering both the molecular aspects underneath the plant-microbe relationship, and also novel applications and approaches exploited to render this technique actually employable in vivo.
We warmly welcome original research articles, method articles, reviews, mini-reviews or perspective articles.