Phyto-rhizoremediation of polychlorinated biphenyl contaminated soils: An outlook on plant-microbe beneficial interactions

Bacteria Associated to Plants Naturally Selected in a Historical PCB Polluted Soil Show Potential to Sustain Natural Attenuation

“…Hence, we applied a cultivation approach to identify indigenous bacteria in the rhizosphere of plants naturally able to cope with the high level of pollution in the SIN Caffaro, having PGP and PCB degrading potentials. The synergistic effect of these traits has indeed the potential to sustain rhizoremediation approaches, in which both plants and bacteria are involved in remediation (Vergani et al, 2017). The cultivation approach applied to MS, CN, DG rhizospheres, due to the selective conditions determined by biphenyl as unique carbon source, led to isolate only bacteria species belonging to three of the thirty-seven phyla identified in the soil metagenome by 16S rRNA high-throughput sequencing ( Actinobacteria, Proteobacteria , and Firmicutes ).…”

“…Root exudates, besides creating a selective ecological niche for specific bacteria, may contain molecules that can induce the expression of genes involved in the PCB degradation pathways, such as the bph operon, in turn stimulating PCB degradation in the rhizosphere (Toussaint et al, 2012; Pham et al, 2015). Rhizoremediation, the exploitation of such positive interactions between plants and bacteria for reclamation of polluted soils, represents a sustainable alternative for clean-up of recalcitrant organic pollutants in extended areas (Vergani et al, 2017). Soil natural attenuation potential therefore relies on the presence, diversity and activity of the resident microbiota, driven by the selecting activity of autochthonous plants.…”

“…A basic question is whether PCB degradation potential is present in the bacterial communities enriched by plants able to grow in the polluted soil, mediated by the selection force determined by the rhizosphere effect. We compared the bacterial communities in the root-associated soil fractions with that of the non-vegetated soil, through 16S rRNA gene phylogenomics and the amplification of the bphA gene, encoding for the α sub-unit of the biphenyl dioxygenase enzyme, a proxy for the PCB degradation ability (Iwai et al, 2010; Sylvestre, 2013; Vergani et al, 2017). By looking to the culturable bacterial fraction, we assessed whether bacteria represent a potentially exploitable resource for rhizoremediation purposes, by assessing their PGP capacity and PCB biodegradation potential.…”

Insights into the Mechanism of Proliferation on the Special Microbes Mediated by Phenolic Acids in the Radix pseudostellariae Rhizosphere under Continuous Monoculture Regimes

“…Root exudates are perceived as chemical signals of communication between roots and microorganisms (Hirsch et al, 2003; Neal et al, 2012; Zhang et al, 2013; Yuan et al, 2015; Rugova et al, 2017; Vergani et al, 2017). A growing body of evidence suggests that the imbalanced microbial populations mediated by the root exudates play crucial roles in replanting disease (Wu et al, 2015).…”

Plant-bacteria synergism: An innovative approach for the remediation of crude oil-contaminated soils

“…This beneficial association relies on the fact that bacteria increase the bioavailability and degradation of organic pollutants, in turn, plants provide residency and food to the bacteria (Muratova et al, 2003;Weyens et al, 2009).Despite the fact that rhizoremediation happens naturally, but through deliberate manipulation (inoculating the soil with contaminant degrading and/or PGP bacteria) in rhizosphere it can be enhanced (Hernández-Vega et al, 2017;Vergani et al, 2017).…”