Effects of Heavy Metal from Polluted Soils on the Rhizobium Diversity

Stan, V.; Gament, Eugenia; Cornea, Călina Petruţa; Voaides, Catalina; Duşa, Mirela; Plopeanu, Georgiana

doi:10.15835/nbha3916081

Cited by 46 publications

(16 citation statements)

References 30 publications

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“…Reductions in bacterial counts of Rhizobium sp. have been reported with the increasing concentrations of heavy metals such as Cu, Zn and Pb, either sole or in combinations, and variations in the expression of symbiotic genes including nod genes (Stan et al 2011 ).…”

Section: Abiotic Stress Resistance Of Rhizobiamentioning

confidence: 99%

Plant growth promoting rhizobia: challenges and opportunities

et al. 2014

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Modern agriculture faces challenges, such as loss of soil fertility, fluctuating climatic factors and increasing pathogen and pest attacks. Sustainability and environmental safety of agricultural production relies on eco-friendly approaches like biofertilizers, biopesticides and crop residue return. The multiplicity of beneficial effects of microbial inoculants, particularly plant growth promoters (PGP), emphasizes the need for further strengthening the research and their use in modern agriculture. PGP inhabit the rhizosphere for nutrients from plant root exudates. By reaction, they help in (1) increased plant growth through soil nutrient enrichment by nitrogen fixation, phosphate solubilization, siderophore production and phytohormones production (2) increased plant protection by influencing cellulase, protease, lipase and β-1,3 glucanase productions and enhance plant defense by triggering induced systemic resistance through lipopolysaccharides, flagella, homoserine lactones, acetoin and butanediol against pests and pathogens. In addition, the PGP microbes contain useful variation for tolerating abiotic stresses like extremes of temperature, pH, salinity and drought; heavy metal and pesticide pollution. Seeking such tolerant PGP microbes is expected to offer enhanced plant growth and yield even under a combination of stresses. This review summarizes the PGP related research and its benefits, and highlights the benefits of PGP rhizobia belonging to the family Rhizobiaceae, Phyllobacteriaceae and Bradyrhizobiaceae.

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Section: Abiotic Stress Resistance Of Rhizobiamentioning

confidence: 99%

Plant growth promoting rhizobia: challenges and opportunities

et al. 2014

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“…Elevated metal concentrations influence microbial populations by affecting their growth, abundance, diversity (11)(12)(13), and activity (14). Metals exert selection pressure on microorganisms, resulting in the emergence of microbial populations with a higher tolerance to metals but with a lower diversity compared to that of unpolluted neighboring areas (11,15,16).…”

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confidence: 99%

Ancient Heavy Metal Contamination in Soils as a Driver of Tolerant Anthyllis vulneraria Rhizobial Communities

Mohamad

Maynaud

Quéré

et al. 2017

Appl Environ Microbiol

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Anthyllis vulneraria is a legume associated with nitrogen-fixing rhizobia that together offer an adapted biological material for mine-soil phytostabilization by limiting metal pollution. To find rhizobia associated with Anthyllis at a given site, we evaluated the genetic and phenotypic properties of a collection of 137 rhizobia recovered from soils presenting contrasting metal levels. Zn-Pb mine soils largely contained metal-tolerant rhizobia belonging to Mesorhizobium metallidurans or to another sister metal-tolerant species. All of the metal-tolerant isolates harbored the cadA marker gene (encoding a metal-efflux P IB -type ATPase transporter). In contrast, metalsensitive strains were taxonomically distinct from metal-tolerant populations and consisted of new Mesorhizobium genospecies. Based on the symbiotic nodA marker, the populations comprise two symbiovar assemblages (potentially related to Anthyllis or Lotus host preferences) according to soil geographic locations but independently of metal content. Multivariate analysis showed that soil Pb and Cd concentrations differentially impacted the rhizobial communities and that a rhizobial community found in one geographically distant site was highly divergent from the others. In conclusion, heavy metal levels in soils drive the taxonomic composition of Anthyllis-associated rhizobial populations according to their metal-tolerance phenotype but not their symbiotic nodA diversity. In addition to heavy metals, local soil physicochemical and topoclimatic conditions also impact the rhizobial beta diversity. Mesorhizobium communities were locally adapted and site specific, and their use is recommended for the success of phytostabilization strategies based on Mesorhizobium-legume vegetation.IMPORTANCE Phytostabilization of toxic mine spoils limits heavy metal dispersion and environmental pollution by establishing a sustainable plant cover. This ecofriendly method is facilitated by the use of selected and adapted cover crop legumes living in symbiosis with rhizobia that can stimulate plant growth naturally through biological nitrogen fixation. We studied microsymbiont partners of a metaltolerant legume, Anthyllis vulneraria, which is tolerant to very highly metal-polluted soils in mining and nonmining sites. Site-specific rhizobial communities were linked to taxonomic composition and metal tolerance capacity. The rhizobial species Mesorhizobium metallidurans was dominant in all Zn-Pb mines but one. It was not detected in unpolluted sites where other distinct Mesorhizobium species occur. Given the different soil conditions at the respective mining sites, including their heavymetal contamination, revegetation strategies based on rhizobia adapting to local conditions are more likely to succeed over the long term compared to strategies based on introducing less-well-adapted strains.

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“…It has been showed that with the elevated concentrations of heavy metals such as copper, zinc, and lead, the numbers of nitrogen fixing organisms like Rhizobium sp . cells are decreased and also their nod genes expression are interrupted . Moreover, it was suggested that the soil content of microbial biomass and their activity are used as good indicators for the level of heavy metals‐contaminated soil .…”

Section: Introductionmentioning

confidence: 99%

Isolation and molecular characterization of Frankia strains resistant to some heavy metals

et al. 2018

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Frankia strains isolated from Saudi Arabia, reported for the first time, were identified based on the morphological and molecular tools compared to those isolated from Egypt. All strains displayed typical morphological characterization of Frankia strains represented by branched hyphae, production of vesicles and sporangia. The phylogenetic analysis and relationships among Frankia strains were investigated by comparing 16S rRNA gene sequences. The analysis revealed three genetic groups which formed two clusters. The first cluster was composed of eight Frankia strains subdivided into two genetic groups (one group containing five strains; CgIT L , CgIS N , CgIS N CgIT7N2, and G5; the other group included of three strains: CgIT5L3, CgIS N , and CcI13). The second cluster was composed of only one genetic group of Frankia strain CgIS N . The strains in each genetic group exhibited similar genetic distances. All Frankia strains were able to reinfect their host of Casuarina species. For ability of these strains to resist heavy metals, our results proved that all Frankia strains isolated can resist Cu, Co, and Zn at low concentration except Pb which exhibit highly toxic effect at the same concentration used. Frankia strain G5 was proved to be the most resistant strain for heavy metals tested.

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Effects of Heavy Metal from Polluted Soils on the Rhizobium Diversity

Cited by 46 publications

References 30 publications

Plant growth promoting rhizobia: challenges and opportunities

Plant growth promoting rhizobia: challenges and opportunities

Ancient Heavy Metal Contamination in Soils as a Driver of Tolerant Anthyllis vulneraria Rhizobial Communities

Isolation and molecular characterization of Frankia strains resistant to some heavy metals

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