Secondary plant metabolites and root exudates: guiding tools for polychlorinated biphenyl biodegradation

Abstract

Synthetic organic compounds are hallmark of modern society. They are ubiquitous ranging from home, workplace to agriculture industry, which leads to their nonjudicious dispensing into environment. Unfortunately most of them, especially polychlorinated biphenyls (PCBs), are deemed as persistent organic pollutants posing serious health risks to human. Hence, there is an alarming need of phasing out these chemicals and remediating contaminated sites in eco-friendly manner. Phytoremediation has emerged as a highly promising approach which capitalizes on plants and their associated microorganisms for removal of pollutants from targeted sites. Plant root exudations and secondary metabolites efficiently orchestrate selective recruitment of potential PCB-degrading microbial consortia within the rhizosphere and inside plant tissues. Structural analogy between organic contaminants and secondary plant metabolites (SPMEs) renders possible uptake and subsequent degradation of pollutants by microorganisms. Present review is focused on potential role of plant root exudates and SPMEs in structuring and orchestrating remediation of PCBs within rhizosphere and inside plant tissues. Also, recent developments in tools and techniques to study remediation of organic contaminants with special reference to PCBs are addressed.

Plant–bacteria partnerships for the remediation of persistent organic pollutants

“…Recently, the combined use of plants and bacteria has been exploited to enhance the phytoremediation of soil and water contaminated with different organic pollutants (Afzal et al 2014b;Arslan et al 2014;Khan et al 2013b;Shehzadi et al 2014). Similarly, several studies were performed to explore the potential of plant-bacteria partnership for the remediation of POPscontaminated soil and water (Aken et al 2009;BecerraCastro et al 2013;Jha and Jha 2015;Jha et al 2014). Both rhizosphere and endophytic bacteria can enhance plant growth and POP degradation.…”

Harnessing plant-bacteria-fungi interactions to improve plant growth and degradation of organic pollutants

“…Rhizodeposits play an important role in selecting the rhizosphere microbiome (Bulgarelli et al 2013;Jha et al 2014). Therefore, there has been a major interest in changing the quality and/or quantity of root exudates via plant breeding or genetic engineering to selectively enhance specific microbial colonization (van Aken et al 2010;Bakker et al 2012).…”

Mechanistic insights on plant root colonization by bacterial endophytes: a symbiotic relationship for sustainable agriculture

“…Chemical signaling between plant roots and soil microorganisms is often driven by root-derived chemical elicitors behaving differently for recipient bacteria. The root exudates may discourage one microorganism while promote another by a process more commonly known as rhizoengineering (Jha et al 2015;Fig. 3).…”