title: Implication of citrate, malate and histidine in the accumulation and transport of nickel in Mesembryanthemum crystallinum and Brassica juncea.
abstract: Citrate, malate and histidine have been involved in many processes including metal tolerance and accumulation in plants. These molecules have been frequently reported to be the potential nickel chelators, which most likely facilitate metal transport through xylem. In this context, we assess here, the relationship between organics acids and histidine content and nickel accumulation in Mesembryanthemum crystallinum and Brassica juncea grown in hydroponic media added with 25, 50 and 100 µM NiCl2. Results showed that M. crystallinum is relatively more tolerant to Ni toxicity than B. juncea. For both species, xylem transport rate of Ni increased with increasing Ni supply. A positive correlation was established between nickel and citrate concentrations in the xylem sap. In the shoot of B. juncea, citric and malic acids concentrations were significantly higher than in the shoot of M. crystallinum. Also, the shoots and roots of B. juncea accumulated much more histidine. In contrast, a higher root citrate concentration was observed in M. crystallinum. These findings suggest a specific involvement of malic and citric acid in Ni translocation and accumulation in M. crystallinum and B. juncea. The high citrate and histidine accumulation especially at 100µM NiCl2, in the roots of M. crystallinum might be among the important factors associated with the tolerance of this halophyte to toxic Ni levels.
authors.affiliation: Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia. Electronic address: taoufik.amari@gmail.com.
authors.forename: Taoufik
authors.initials: T
authors.lastname: Amari
authors.affiliation: Groupe de Recherche en Physiologie végétale (GRPV), Earth and Life Institute - Agronomy - Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Stanley
authors.initials: S
authors.lastname: Lutts
authors.affiliation: Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia.
authors.forename: Manel
authors.initials: M
authors.lastname: Taamali
authors.affiliation: Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, 20133 Milan, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Lucchini
authors.affiliation: Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, 20133 Milan, Italy.
authors.forename: Gian Attilio
authors.initials: GA
authors.lastname: Sacchi
authors.affiliation: Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia.
authors.forename: Chedly
authors.initials: C
authors.lastname: Abdelly
authors.affiliation: Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia.
authors.forename: Tahar
authors.initials: T
authors.lastname: Ghnaya
mesh_terms: D001692:Biological Transport / Q000502:physiology; D019343:Citric Acid / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism*; D008293:Malates / Q000378:metabolism*; D035723:Mesembryanthemum / Q000378:metabolism*; D009149:Mustard Plant / Q000378:metabolism*; D009532:Nickel / Q000493:pharmacokinetics*; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D055051:Salt-Tolerant Plants; D052584:Xylem
chemical_list: D008293:Malates; D019343:Citric Acid; D006639:Histidine; D009532:Nickel; C030298:malic acid
keywords: Citrate; Halophyte; Histidine; Malate; Nickel; Tolerance