Bacterial community shaped by heavy metals and contributing to health risks in cornfields

The Aromatic Plant Clary Sage Shaped Bacterial Communities in the Roots and in the Trace Element-Contaminated Soil More Than Mycorrhizal Inoculation – A Two-Year Monitoring Field Trial

“…Thus, the shift observed with the culture duration in both biotopes but particularly pronounced in the case of roots, at the phylum and genus phylogenetic levels, could be explained by different factors. First, the prevalence in year 2 for both root and rhizospheric soil biotopes of Actinobacteria, previously demonstrated as TE-tolerant, could support the idea that the phylotypes possessing TE tolerance are susceptible to persist overtime, while sensitive ones become less frequent (Cui et al, 2018). In addition, it was previously evidenced for wheat grown in uncontaminated agricultural fields that Actinobacteria abundance was increasing with root age, which is possibly explained by their ability to degrade secondary cell walls containing complex molecules (Donn et al, 2015).…”

“…Interestingly, among the identified phyla, Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes were previously demonstrated to possess TE-tolerance genes, coding for proteins involved in efflux and sequestration phenomena of TE ions, such as Cu 2+ or Cd 2+ /Zn 2+ -exporting ATPases, putative copper resistance protein D or copper transport protein B and in the mitigation of oxidative stress induced by the presence of TE, such as superoxide dismutase, alkyl hyperoxide reductase or mycothiol reductase (Chen et al, 2018;Cui et al, 2018;Hemmat-Jou et al, 2018). Besides, Actinobacteria and Proteobacteria, which are the two prevailing bacteria phyla in the present work whatever the biotope, were previously brought forward as reducing TE accumulation in corn.…”

“…Besides, Actinobacteria and Proteobacteria, which are the two prevailing bacteria phyla in the present work whatever the biotope, were previously brought forward as reducing TE accumulation in corn. Notably, it is believed that both bacterial phyla could alter the bioavailability of heavy metals via redox reactions, precipitation, as well as sorption and desorption reactions (Cui et al, 2018). More specifically, Bacillus, Pseudomonas and Arthrobacter, respectively, belonging Streptomyces 0.4 ± 0.06 de 0.4 ± 0.03 de 3.2 ± 0.3 c 52.5 ± 1.5 a 50.4 ± 1.0 a 1.3 ± 0.7 cd 1.2 ± 0.5 cd 3.6 ± 3.6 c 3.9 ± 1.8 c…”

“…to Firmicutes, Proteobacteria, and Actinobacteria phyla, are among the most widely spread and frequently listed bacterial genera in TE-contaminated soils, and at the same time display a high TE tolerance (Pires et al, 2017;Chellaiah, 2018;Chen et al, 2018;Cui et al, 2018). Nonetheless, Sphingomonas, member of the Proteobacteria (Xie et al, 2010;Chen et al, 2014;Jaafar, 2019), as well as Pseudarthrobacter (Chen et al, 2014;Fekih et al, 2018;Park et al, 2019), Nocardioides (Bagade et al, 2016;Cui et al, 2018), and Streptomyces (Álvarez et al, 2013;Cui et al, 2018;Durand et al, 2018;Lasudee et al, 2018;Timková et al, 2018;Álvarez-López et al, 2020), belonging to the Actinobacteria, were also highlighted for displaying TE-tolerance and even studied for potential remediation applications. Indeed, these bacterial genera are known to accumulate Cd, Ni, Cr or Pb from TE-contaminated soils and to induce changes in the oxidation state of the TE (Pires et al, 2017;Chellaiah, 2018;Timková et al, 2018).…”

Distribution Characteristics and Pollution Assessment of Soil Heavy Metals under Different Land-Use Types in Xuzhou City, China

“…In terms of farmland soils, anthropogenic metal inputs, mainly including sewage irrigation and the application of fertilizers, have resulted in the increase of heavy metal concentration [9]. Meanwhile, crops (e.g., wheat, corn) can contribute to the migration and transformation of heavy metal by their enrichment capacity [10,11]. Industrial and domestic waste, vehicle exhaust, and slag have been proven to the major sources of soil heavy metals of the built-up area and mining area.…”