title: A Cd/Fe/Zn-responsive phytochelatin synthase is constitutively present in the ancient liverwort Lunularia cruciata (L.) dumort.
abstract: Lunularia cruciata occupies a very basal position in the phylogenetic tree of liverworts, which in turn have been recognized as a very early clade of land plants. It would therefore seem appropriate to take L. cruciata as the startingpoint for investigating character evolution in plants' metal(loid) response. One of the strongest evolutionary pressures for land colonization by plants has come from potential access to much greater amounts of nutritive ions from surface rocks, compared to water. This might have resulted in the need to precisely regulate trace element homeostasis and to minimize the risk of exposure to toxic concentrations of certain metals, prompting the evolution of a number of response mechanisms, such as synthesis of phytochelatins, metal(loid)-binding thiol-peptides. Accordingly, if the ability to synthesize phytochelatins and the occurrence of an active phytochelatin synthase are traits present in a basal liverwort species, and have been even reinforced in 'modern' tracheophytes, e.g. Arabidopsis thaliana, then such traits would presumably have played an essential role in plant fitness over time. Hence, we demonstrated here that: (i) L. cruciata compartmentalizes cadmium in the vacuoles of the phototosynthetic parenchyma by means of a phytochelatin-mediated detoxification strategy, and possesses a phytochelatin synthase that is activated by cadmium and homeostatic concentrations of iron(II) and zinc; and (ii) A. thaliana phytochelatin synthase displays a higher and broader response to several metal(loid)s [namely: cadmium, iron(II), zinc, copper, mercury, lead, arsenic(III)] than L. cruciata phytochelatin synthase.
authors.affiliation: Department of Life Sciences, University of Parma, I-43124 Parma, Italy Contributed equally to this work and should be considered co-first authors.
authors.forename: Francesca
authors.initials: F
authors.lastname: Degola
authors.affiliation: Department of Life Sciences, University of Parma, I-43124 Parma, Italy Contributed equally to this work and should be considered co-first authors.
authors.forename: Maria
authors.initials: M
authors.lastname: De Benedictis
authors.affiliation: Department of Life Sciences, University of Parma, I-43124 Parma, Italy Contributed equally to this work and should be considered co-first authors.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Petraglia
authors.affiliation: 'Berenini' Institute, I-43036 Fidenza (PR), Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Massimi
authors.affiliation: Department of Environmental Biology, 'Sapienza' University of Rome, I-00185 Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Fattorini
authors.affiliation: CeSMA, Microscopy Section, University of Naples 'Federico II', I-80139 Naples, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Sorbo
authors.affiliation: Department of Biology, University of Naples 'Federico II', I-80137 Naples, Italy.
authors.forename: Adriana
authors.initials: A
authors.lastname: Basile
authors.affiliation: Department of Life Sciences, University of Parma, I-43124 Parma, Italy luigi.sanita@unipr.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Sanità di Toppi
mesh_terms: D019881:Aminoacyltransferases / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism*; D004577:Electron Probe Microanalysis; D019669:Embryophyta / Q000378:metabolism; D055993:Germ Cells, Plant / Q000378:metabolism / Q000648:ultrastructure; D035926:Hepatophyta / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D008658:Inactivation, Metabolic; D007501:Iron / Q000378:metabolism*; D008670:Metals / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology; D008855:Microscopy, Electron, Scanning; D054811:Phytochelatins / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism; D015032:Zinc / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D008670:Metals; D010940:Plant Proteins; D002104:Cadmium; D054811:Phytochelatins; D007501:Iron; D019881:Aminoacyltransferases; C093784:glutathione gamma-glutamylcysteinyltransferase; D015032:Zinc
keywords: Bryophytes; Liverworts; Metalloids; Metals; Phytochelatin synthase; Phytochelatins