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Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR)
BACKGROUND: Soil pollution by heavy metals increases the bioavailability of metals like hexavalent chromium (Cr (VI)), subsequently limiting plant growth and reducing the efficiency of phytoremediation. Plant growth-promoting rhizobacteria (PGPR) have substantial potential to enhance plant growth as...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer Berlin Heidelberg
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8494867/ https://www.ncbi.nlm.nih.gov/pubmed/34613510 http://dx.doi.org/10.1186/s43141-021-00254-8 |
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author | Tirry, Nabil Kouchou, Aziza El Omari, Bouchra Ferioun, Mohamed El Ghachtouli, Naïma |
author_facet | Tirry, Nabil Kouchou, Aziza El Omari, Bouchra Ferioun, Mohamed El Ghachtouli, Naïma |
author_sort | Tirry, Nabil |
collection | PubMed |
description | BACKGROUND: Soil pollution by heavy metals increases the bioavailability of metals like hexavalent chromium (Cr (VI)), subsequently limiting plant growth and reducing the efficiency of phytoremediation. Plant growth-promoting rhizobacteria (PGPR) have substantial potential to enhance plant growth as well as plant tolerance to metal stress. The aim of this research was to investigate Cr (VI) phytoremediation enhancement by PGPR. RESULTS: The results showed that the 27 rhizobacterial isolates studied were confirmed as Cr (VI)-resistant PGPR, by using classical biochemical tests (phosphate solubilization, nitrogen fixation, indole acetic acid, exopolysaccharides, hydrogen cyanide, siderophores, ammonia, cellulase, pectinase, and chitinase production) and showed variable levels of Cr (VI) resistance (300–600 mg/L). The best four selected Cr (VI)-resistant PGPR (NT15, NT19, NT20, and NT27) retained most of the PGP traits in the presence of 100–200 mg/L concentrations of Cr (VI). The inoculation of Medicago sativa with any of these four isolates improved the shoot and root dry weight. The NT27 isolate identified using 16S rDNA gene sequence analyses as a strain of Pseudomonas sp. was most effective in terms of plant growth promotion and stress level decrease. It increased shoot and root dry weights of M. sativa by 97.6 and 95.4%, respectively, in the presence of Cr (VI) when compared to non-inoculated control plants. It also greatly increased chlorophyll content and decreased the levels of stress markers, malondialdehyde, hydrogen peroxide, and proline. The results of the effect of Pseudomonas sp. on Cr content and bioaccumulation factor (BAF) of the shoots and roots of M. sativa plants showed the increase of plant biomass concomitantly with the increase of Cr root concentration in inoculated plants. This would lead to a higher potential of Cr (VI) phytostabilization. CONCLUSIONS: This study demonstrates that the association M. sativa-Pseudomonas sp. may be an efficient biological system for the bioremediation of Cr (VI)-contaminated soils. |
format | Online Article Text |
id | pubmed-8494867 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Springer Berlin Heidelberg |
record_format | MEDLINE/PubMed |
spelling | pubmed-84948672021-10-19 Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR) Tirry, Nabil Kouchou, Aziza El Omari, Bouchra Ferioun, Mohamed El Ghachtouli, Naïma J Genet Eng Biotechnol Research BACKGROUND: Soil pollution by heavy metals increases the bioavailability of metals like hexavalent chromium (Cr (VI)), subsequently limiting plant growth and reducing the efficiency of phytoremediation. Plant growth-promoting rhizobacteria (PGPR) have substantial potential to enhance plant growth as well as plant tolerance to metal stress. The aim of this research was to investigate Cr (VI) phytoremediation enhancement by PGPR. RESULTS: The results showed that the 27 rhizobacterial isolates studied were confirmed as Cr (VI)-resistant PGPR, by using classical biochemical tests (phosphate solubilization, nitrogen fixation, indole acetic acid, exopolysaccharides, hydrogen cyanide, siderophores, ammonia, cellulase, pectinase, and chitinase production) and showed variable levels of Cr (VI) resistance (300–600 mg/L). The best four selected Cr (VI)-resistant PGPR (NT15, NT19, NT20, and NT27) retained most of the PGP traits in the presence of 100–200 mg/L concentrations of Cr (VI). The inoculation of Medicago sativa with any of these four isolates improved the shoot and root dry weight. The NT27 isolate identified using 16S rDNA gene sequence analyses as a strain of Pseudomonas sp. was most effective in terms of plant growth promotion and stress level decrease. It increased shoot and root dry weights of M. sativa by 97.6 and 95.4%, respectively, in the presence of Cr (VI) when compared to non-inoculated control plants. It also greatly increased chlorophyll content and decreased the levels of stress markers, malondialdehyde, hydrogen peroxide, and proline. The results of the effect of Pseudomonas sp. on Cr content and bioaccumulation factor (BAF) of the shoots and roots of M. sativa plants showed the increase of plant biomass concomitantly with the increase of Cr root concentration in inoculated plants. This would lead to a higher potential of Cr (VI) phytostabilization. CONCLUSIONS: This study demonstrates that the association M. sativa-Pseudomonas sp. may be an efficient biological system for the bioremediation of Cr (VI)-contaminated soils. Springer Berlin Heidelberg 2021-10-06 /pmc/articles/PMC8494867/ /pubmed/34613510 http://dx.doi.org/10.1186/s43141-021-00254-8 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Research Tirry, Nabil Kouchou, Aziza El Omari, Bouchra Ferioun, Mohamed El Ghachtouli, Naïma Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR) |
title | Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR) |
title_full | Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR) |
title_fullStr | Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR) |
title_full_unstemmed | Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR) |
title_short | Improved chromium tolerance of Medicago sativa by plant growth-promoting rhizobacteria (PGPR) |
title_sort | improved chromium tolerance of medicago sativa by plant growth-promoting rhizobacteria (pgpr) |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8494867/ https://www.ncbi.nlm.nih.gov/pubmed/34613510 http://dx.doi.org/10.1186/s43141-021-00254-8 |
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