Cross-tolerance to abiotic stresses in halophytes: Application for phytoremediation of organic pollutants

International audienceHalopytes are plants able to tolerate high salt concentrations but no clear definition was retained for them. In literature, there are more studies that showed salt-enhanced tolerance to other abiotic stresses compared to investigations that found enhanced salt tolerance by other abiotic stresses in halophytes. The phenomenon by which a plant resistance to a stress induces resistance to another is referred to as cross-tolerance. In this work, we reviewed cross-tolerance in halophytes at the physiological, biochemical, and molecular levels. A special attention was accorded to the cross-tolerance between salinity and organic pollutants that could allow halophytes a higher potential of xenobiotic phytoremediation in comparison with glycophytes

Molecular study of the perforin gene in familial hematological malignancies

Perforin gene (PRF1) mutations have been identified in some patients diagnosed with the familial form of hemophagocytic lymphohistiocytosis (HLH) and in patients with lymphoma. The aim of the present study was to determine whether patients with a familial aggregation of hematological malignancies harbor germline perforin gene mutations. For this purpose, 81 unrelated families from Tunisia and France with aggregated hematological malignancies were investigated. The variants detected in the PRF1 coding region amounted to 3.7% (3/81). Two of the three variants identified were previously described: the p.Ala91Val pathogenic mutation and the p.Asn252Ser polymorphism. A new p.Ala 211Val missense substitution was identified in two related Tunisian patients. In order to assess the pathogenicity of this new variation, bioinformatic tools were used to predict its effects on the perforin protein structure and at the mRNA level. The segregation of the mutant allele was studied in the family of interest and a control population was screened. The fact that this variant was not found to occur in 200 control chromosomes suggests that it may be pathogenic. However, overexpression of mutated PRF1 in rat basophilic leukemia cells did not affect the lytic function of perforin differently from the wild type protein

Physico-chemical and microbiological characterization of olive mill wastewater (OMW) of different regions of Tunisia (North, Sahel, South)

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Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: Implication of organic acids in these processes

The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic, and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 μM Cd, 100 μM Ni and the combination of 50 μM Cd + 100 μM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected plant development. Cadmium and Ni concentrations in tissues and xylem sap were higher in plants subjected to individual metal application than those subjected to the combined effect of Cd and Ni suggesting a possible competition between these metals for absorption. Both metals applied separately or in combination induced an increase in citrate concentration in shoots and xylem sap but a decrease of this concentration in the roots. However, a minor relationship was observed between metal application and fumaric, malic, and ascorbic acids. Both observations suggest the implication of citric acid in Cd, Ni translocation and shoot accumulation in S. portulacastrum. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could be involved in metal chelation and thus contributes to heavy metal tolerance in this species. © 2015 Mnasri,Ghabriche,Fourati,Zaier,Sabally,Barrington,Lutts, AbdellyandGhnaya

Evaluation of the Cd2+ phytoextraction potential in the xerohalophyte Salsola kali L. and the impact of EDTA on this process

The application of the phytoextraction in saline soil contaminated with heavy metals requires the identification of appropriate plant species showing high salinity tolerance concomitant with an important ability of heavy metal accumulation. The objective of this works is to evaluate the capacity of the xerohalophyte, Salsola kali, to extract Cd2+ from an artificially contaminated soil (100μg Cd2+g-1 soil) in the presence of NaCl (100mM) and/or EDTA (1mmolkg-1 soil). Results showed that in the absence of NaCl or EDTA, Cd2+ was essentially accumulated in the roots reaching 400μg Cd2+g-1 DW, while in the shoots Cd2+ concentration did not exceed 85μg Cd2+g-1 DW. Addition of NaCl to the soil significantly reduced root Cd2+ concentration, but had no impact on Cd2+ concentration in the shoots. The addition of the EDTA results in a twofold increase of Cd2+ concentration in shoots. This is due to the improvement of Cd2+ absorption efficiency by the EDTA concomitant with an increase of Cd2+ translocation to the shoots. These data suggest that S. kali is very promising species for the decontamination of Cd2+ contaminated salty soil. Its phytoextraction potential was significantly enhanced by the addition of EDTA. © 2013 Elsevier B.V