The inoculation with Ensifer meliloti sv. rigiduloides improves considerably the growth of Robinia pseudoacacia under lead-stress.

Autor: Alami, Soufiane, Bennis, Meryeme, Lamin, Hanane, Kaddouri, Kaoutar, Bouhnik, Omar, Lamrabet, Mouad, Chaddad, Zohra, Mnasri, Bacem, Abdelmoumen, Hanaa, Bedmar, Eulogio J., Missbah El Idrissi, Mustapha
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Zdroj: Plant & Soil; Apr2024, Vol. 497 Issue 1/2, p119-137, 19p
Abstrakt: Aims: In Morocco, the Zaida abandoned mine is a major source of metallic trace elements that are harmful to the environment and human health. With the aim to use the heavy metal tolerant legume tree Robinia pseudoacacia in the phytostabilization of this mine's tailings, we isolated and characterized its indigenous microsymbionts, and tested their effects on the plant growth under high Pb-acetate concentrations. Methods: Thus, 27 bacteria were isolated from nodules of the plant grown in the Zaida abandoned mine tailings, and we examined their tolerance to high concentrations of Pb-acetate in-vitro. Four strains were then selected for symbiotic, molecular, and phenotypic analyses, and we analyzed the effect of inoculation on the plant growth parameters under increasing Pb-acetate concentrations (in-vivo). Results: The isolated strains tolerate high lead concentrations. The Phylogenetic analyses of 16 S rRNA, five housekeeping genes (MLSA), and three symbiotic genes showed the affiliation of the strains with Ensifer meliloti sv. rigiduloides and E. kummerowiae sv. meliloti. Representative strains of both symbiovars tolerate 1100 µg ml− 1 Pb-acetate in-vitro and nodulate R. pseudoacacia even under 1200 µg ml− 1 of Pb-acetate. In all tests, the plant proline content increased as a response mechanism to increasing concentrations of Pb-acetate. Inoculation experiments under high concentrations of Pb-acetate showed that both strains improved the plant growth parameters and chlorophyll content compared to controls. Conclusion: Our results show that E. meliloti sv. rigiduloides strain RPZ12 improves plant growth under Pb stress conditions more than E. kummerowiae sv. meliloti strain RPZ17. Strain RPZ12 would be an excellent inoculum to use for the phytostabilization of Zaida mine tailings. This is the first description of symbiovar meliloti in E. kummerowiae. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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