Luigi Sanità di Toppi

Università degli studi di Parma, Parma, Emilia-Romagna, Italy

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Publications (47)119.38 Total impact

  • [Show abstract] [Hide abstract]
    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 starting point for investigating character evolution in the metal(loid) response of land plants. 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. 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, 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: 1) 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; 2) 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 the phytochelatin synthase of L. cruciata.
    Plant and Cell Physiology 09/2014; · 4.98 Impact Factor
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    109° Congresso Nazionale della Società Botanica Italiana - International Plant Science Conference, Firenze (FI); 09/2014
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    ABSTRACT: A recent study by our group demonstrated that bryophytes - a paraphyletic group which includes liverworts (Marchantiophyta), mosses (Bryophyta) and hornworts (Anthocerotophyta) - have the capability to produce phytochelatins (PCs) in response to Cd, and that they possess a constitutive and functional phytochelatin synthase (PCS). Amongst bryophytes, liverworts occupy an ideal basal phylogenetic position for reconstructing ancient evolutionary changes that occurred over time. Notably, the early Devonian Rhynie Chert of NE Scotland (ca. 396 ± 12 Mya) contained the earliest bryophytic flora and featured high levels of Hg, Zn, Au, the metalloids As and Sb, etc., all PC-inducers to varying extents, at least in higher plants. Accordingly, if the PC production capability and a functional PCS were present even in the earliest land plants (such as ancient liverworts) and have been maintained until today, it might be postulated that PCs and PCS would have played a positive role for plant fitness in metal(loid)-containing palaeoenvironments over the course of time. Thus, in order to identify events of an ancestral nature in the basalmost land plants, we hypothesized here that gametophytes of Lunularia cruciata (Lunulariales, Lunulariaceae), an early divergent clade of thalloid liverworts, would: 1) possess a metal(loid)-responsive PCS activated by Cd and other elements, such as Hg, Pb, Zn, Cu, As, and Sb, which are documented to be present both in the abovementioned palaeoenvironments, and in the present-day environments; 2) compartmentalize the excess of certain metals, i.e. Cd and Zn, in the vacuoles, by means of a PC-mediated detoxification strategy.
    PLANT BIOLOGY EUROPE FESPB/EPSO 2014 Congress, Dublin, Ireland; 06/2014
  • F. Degola, P. Margaria, S. Palmano, L. Sanità di Toppi
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    ABSTRACT: The grapevine (Vitis vinifera) disease caused by Bois Noir (BN) phytoplasma, a plant phloem-limited pathogens belonging to the class Mollicutes, is an important concern to European vinery economy. Phytoplasmas have a broad range of plant hosts among monocots and dicots and diseases of many important crops have already been associated with these pathogens. Leaf curling and discoloration, uneven or total lack of lignification of canes, flower abortion and berry withering are the typical symptoms of phytoplasma infection in grapevine. An interesting aspect of the pathogen–plant interaction is “recovery” phenomenon, a spontaneous remission of symptoms in previously symptomatic plants. In this study, we are using 2-DE and Western Blot analysis to explore the proteome changes in leaves and midribs of V. vinifera cv. 'Chardonnay' naturally infected by BN, with particular attention to recovered plants.
    PLANT BIOLOGY EUROPE FESPB/EPSO 2014 Congress, Dublin, Ireland; 06/2014
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    ABSTRACT: Bryophytes, a paraphyletic group which includes liverworts, mosses, and hornworts, have been stated as land plants that under metal stress (particularly cadmium) do not synthesize metal-binding peptides such as phytochelatins. Moreover, very little information is available to date regarding phytochelatin synthesis in charophytes, postulated to be the direct ancestors of land plants, or in lycophytes, namely very basal tracheophytes. In this study, it was hypothesized that basal land plants and charophytes have the capability to produce phytochelatins and possess constitutive and functional phytochelatin synthases. To verify this hypothesis, twelve bryophyte species (six liverworts, four mosses, and two hornworts), three charophytes, and two lycophyte species were exposed to 0-36 μM cadmium for 72h, and then assayed for: (i) glutathione and phytochelatin quali-quantitative content by HPLC and mass spectrometry; (ii) the presence of putative phytochelatin synthases by western blotting; and (iii) in vitro activity of phytochelatin synthases. Of all the species tested, ten produced phytochelatins in vivo, while the other seven did not. The presence of a constitutively expressed and functional phytochelatin synthase was demonstrated in all the bryophyte lineages and in the lycophyte Selaginella denticulata, but not in the charophytes. Hence, current knowledge according to phytochelatins have been stated as being absent in bryophytes was therefore confuted by this work. It is argued that the capability to synthesize phytochelatins, as well as the presence of active phytochelatin synthases, are ancestral (plesiomorphic) characters for basal land plants.
    Journal of Experimental Botany 01/2014; · 5.79 Impact Factor
  • F. Degola, M. Maurizio, L. Sanità di Toppi
    108° Congresso Nazionale della Società Botanica Italiana, Baselga di Pinè (TN); 09/2013
  • 108° Congresso Nazionale della Società Botanica Italiana, Baselga di Pinè (TN); 09/2013
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    ABSTRACT: Bryophytes, namely liverworts, mosses and hornworts, have been stated as basal land plants that, under metal stress (particularly cadmium), do not synthesize metal-binding peptides such as phytochelatins. We hypothesized instead that a “phytochelatin production capability” may be present also in these plants. For verifying such hypothesis, twelve bryophyte species (six liverworts, Conocephalum conicum, Marchantia polymorpha, Pellia epiphylla, Radula complanata, Aneura pinguis and Scapania undulata; four mosses, Sphagnum palustre, Polytrichastrum formosum, Hypnum cupressiforme and Fontinalis antipyretica; and two hornworts, Anthoceros punctatus and Phaeoceros laevis) were grown with or without 36 microM cadmium for 72 h, and then assayed for phytochelatin quali-quantitative content by post-column-derivatized HPLC followed by mass and mass/ mass spectrometry. In addition, western blot analyses for immunodetection of putative phytochelatin synthases were performed in C. conicum, S. palustre, P. laevis and, as a negative control, in Physcomitrella patens, whose genome is completely sequenced. Of the twelve species tested, six produced phytochelatins (four liverworts, one moss, one hornwort), whereas six did not. Not least, the presence of an endogenous, constitutivelyexpressed, phytochelatin synthase was also found in some species. Hence, bryophytes do produce phytochelatins, thus confuting the current knowledge according to which these thiol-peptides are absent in such plants; besides, phytochelatins were mainly detected in stem lineages, whereas they appeared to be less abundant (or absent) in crown taxa. This suggests that phytochelatin synthesis, as well as the presence of a constitutive phytochelatin synthase, is an ancestral character for basal land plants.
    25th Congress of the Scandinavian Plant Physiology Society, Helsingør, Denmark; 08/2013
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    ABSTRACT: Very few studies have provided information about the effects of cadmium (Cd) at histoanatomical and ultrastructural levels, along with potential localization of the metal in planta. In particular, from this standpoint, almost nothing is known in Daucus carota L. (carrot), a particularly important species for in vitro and in vivo functional investigations. In this work we hypothesized that 36 μM Cd, supplied for 1, 2, 3, 4, 7 and 14 days to 30-day-old in vitro-cultured plants, might induce an early acclimation, but a final collapse of roots and leaves. In fact, as a general feature, a biphasic root response to Cd stress actually took place: in the first phase (1-4 days of Cd exposure), the cytological and functional events observed - by light microscopy, TEM, epifluorescence, as well as by the time-course of thiol-peptide compounds - can be interpreted as acclimatory responses aimed at diminishing the movement of Cd across the root. The second phase (from 4 to 14 days of Cd exposure) was instead characterized by cell hypertrophy, cell-to-cell separation events, increase in α-β-γ-tocopherol levels and, not least, endocytogenic processes, coupled with a dramatic drop in the amount of thiol-peptide compounds. These events led to a progressive root collapse, even if they did not ingenerate macro/microscopic injury symptoms in leaf blades and petioles.
    Plant Physiology and Biochemistry 07/2012; 58:269-79. · 2.78 Impact Factor
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    ABSTRACT: Indian mustard (Brassica juncea L. Czern.) tolerates high concentrations of heavy metals and is a promising species for the purpose of phytoextraction of cadmium (Cd) from metal-contaminated soils. This work investigates the extent to which antioxidant and metal sequestering mechanisms are responsible for this tolerance. To this end, seedlings of Indian mustard were grown for 7 days in 0, 50 or 200 μM Cd. Increasing Cd concentrations led to a progressive Cd accumulation in roots and shoots, accompanied by an organ-dependent alteration in mineral uptake, and a decrease in root/shoot length and fresh/dry weight. Cd negatively affected chlorophyll and carotenoid contents and activated the xanthophyll cycle, suggesting the need to protect the photosynthetic apparatus from photoinhibition. Shoots seemed to be less efficient than roots in ROS scavenging, as indicated by the different response to Cd stress shown by peroxidase and catalase activities and, solely with regard to the highest Cd concentration, by ascorbate level. Such a different antioxidant capacity might at least partly explain differences in the trend of lipid peroxidation observed in the two organs. Moreover, in both roots and shoots, glutathione and phytochelatin content markedly increased under Cd stress, regardless of the metal concentration involved.
    Plant Physiology and Biochemistry 05/2012; 57:15-22. · 2.78 Impact Factor
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    S Astolfi, S Zuchi, G Neumann, S Cesco, L Sanità di Toppi, R Pinton
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    ABSTRACT: Both Fe deficiency and Cd exposure induce rapid changes in the S nutritional requirement of plants. The aim of this work was to characterize the strategies adopted by plants to cope with both Fe deficiency (release of phytosiderophores) and Cd contamination [production of glutathione (GSH) and phytochelatins] when grown under conditions of limited S supply. Experiments were performed in hydroponics, using barley plants grown under S sufficiency (1.2 mM sulphate) and S deficiency (0 mM sulphate), with or without Fe(III)-EDTA at 0.08 mM for 11 d and subsequently exposed to 0.05 mM Cd for 24 h or 72 h. In S-sufficient plants, Fe deficiency enhanced both root and shoot Cd concentrations and increased GSH and phytochelatin levels. In S-deficient plants, Fe starvation caused a slight increase in Cd concentration, but this change was accompanied neither by an increase in GSH nor by an accumulation of phytochelatins. Release of phytosiderophores, only detectable in Fe-deficient plants, was strongly decreased by S deficiency and further reduced after Cd treatment. In roots Cd exposure increased the expression of the high affinity sulphate transporter gene (HvST1) regardless of the S supply, and the expression of the Fe deficiency-responsive genes, HvYS1 and HvIDS2, irrespective of Fe supply. In conclusion, adequate S availability is necessary to cope with Fe deficiency and Cd toxicity in barley plants. Moreover, it appears that in Fe-deficient plants grown in the presence of Cd with limited S supply, sulphur may be preferentially employed in the pathway for biosynthesis of phytosiderophores, rather than for phytochelatin production.
    Journal of Experimental Botany 11/2011; 63(3):1241-50. · 5.79 Impact Factor
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    ABSTRACT: The hypothesis that a daily water supply allows a lichen to endure the negative effects of environmental concentrations of NO(x) and O(3) was tested with a transplant experiment. Five groups (0, A-D) of Flavoparmelia caperata samples derived from the same thalli were used for destructive, pre-exposure measurements (0), or exposed for 5 weeks in the rural collection site (A), and in a urban site with high levels of NO(x) and O(3) (B-D). Two groups (C, D) were daily watered half an hour before the daily peak of NO(x) (C), and O(3) (D). The comparison between pre- and post-exposure measurements of stress biomarkers revealed that the different thallus hydration regime modified the pollution tolerance as well as the physiology of the exposed samples. The non-watered group B suffered an evident decrease in F(v)/F(m) and reduced glutathione, but increased ion leakage, whereas the watered groups C and D showed only decreased non-photosynthetic-quenching, possibly derived from NO(x) exposure. Ozone, which was higher in the rural than in the urban site, did not significantly affect the lichen metabolism. Our results re-open the discussion on the so-called "drought hypothesis", which suggests that the lichen desert observed in urban areas of central and eastern Europe is more a matter of dry microclimate than of air pollution.
    Oecologia 08/2011; 168(2):589-99. · 3.01 Impact Factor
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    ABSTRACT: Previous studies demonstrated that expression of the Arabidopsis phytochelatin (PC) biosynthetic gene AtPCS1 in Nicotiana tabacum plants increases the Cd tolerance in the presence of exogenous glutathione (GSH). In this paper, the Cd tolerance of Arabidopsis plants over-expressing AtPCS1 (AtPCSox lines) has been analysed and the differences between Arabidopsis and tobacco are shown. Based on the analysis of seedling fresh weight, primary root length, and alterations in root anatomy, evidence is provided that, at relatively low Cd concentrations, the Cd tolerance of AtPCSox lines is lower than the wild type, while AtPCS1 over-expressing tobacco is more tolerant to Cd than the wild type. At higher Cd concentrations, Arabidopsis AtPCSox seedlings are more tolerant to Cd than the wild type, while tobacco AtPCS1 seedlings are as sensitive as the wild type. Exogenous GSH, in contrast to what was observed in tobacco, did not increase the Cd tolerance of AtPCSox lines. The PC content in wild-type Arabidopsis at low Cd concentrations is more than three times higher than in tobacco and substantial differences were also found in the PC chain lengths. These data indicate that the differences in Cd tolerance and in its dependence on exogenous GSH between Arabidopsis and tobacco are due to species-specific differences in the endogenous content of PCs and GSH and may be in the relative abundance of PCs of different length.
    Journal of Experimental Botany 08/2011; 62(15):5509-19. · 5.79 Impact Factor
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    ABSTRACT: Cuscuta sp., known with the common name of “dodder”, is an obligate parasite capable of invading stems and leaves of a wide range of host plants. Dodder stem usually coils counterclockwise around the host and, within a few days, develops haustorial structures at each point of contact. As soon as dodder haustoria reach host vascular bundles, they start tapping water, photosynthates and minerals. Metal ions such as zinc (Zn) and copper (Cu) are essential for dodder growth and metabolism, although an exceedingly high (over-homeostatic) supply of these micronutrients can result in growth inhibition and cellular toxicity. Even more so, non-essential metals such as cadmium (Cd), if transferred from the host to the parasite, need to be neutralized by timely detoxification mechanisms. In this work, we showed that Cuscuta campestris Yuncker establishes effective haustorial connections with leaf petioles and blades of Daucus carota L. (carrot), with the consequent transfer of Cd and essential metals (such as Zn and Cu) from the host vascular bundles to the parasite. Following up to this point, we detected the presence in the parasite of significant amounts of glutathione and phytochelatins, even in the absence of Cd exposure. This suggests that thiol peptides in dodder might be particularly important for Zn and Cu homeostasis as well as for Cd detoxification. Finally, we demonstrated that dodder is capable of synthesizing phytochelatins on its own, rather than massively importing them from the host, and also provided evidence for the existence of an endogenous, constitutively expressed, dodder's phytochelatin synthase.
    Environmental and Experimental Botany 08/2011; 72(1):26-33. · 3.00 Impact Factor
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    ABSTRACT: Pteris vittata can tolerate very high soil arsenic concentration and rapidly accumulates the metalloid in its fronds. However, its tolerance to arsenic has not been completely explored. Arbuscular mycorrhizal (AM) fungi colonize the root of most terrestrial plants, including ferns. Mycorrhizae are known to affect plant responses in many ways: improving plant nutrition, promoting plant tolerance or resistance to pathogens, drought, salinity and heavy metal stresses. It has been observed that plants growing on arsenic polluted soils are usually mycorrhizal and that AM fungi enhance arsenic tolerance in a number of plant species. The aim of the present work was to study the effects of the AM fungus Glomus mosseae on P. vittata plants treated with arsenic using a proteomic approach. Image analysis showed that 37 spots were differently affected (21 identified). Arsenic treatment affected the expression of 14 spots (12 up-regulated and 2 down-regulated), while in presence of G. mosseae modulated 3 spots (1 up-regulated and 2 down-regulated). G. mosseae, in absence of arsenic, modulated 17 spots (13 up-regulated and 4 down-regulated). Arsenic stress was observed even in an arsenic tolerant plant as P. vittata and a protective effect of AM symbiosis toward arsenic stress was observed.
    Journal of proteomics 03/2011; 74(8):1338-50. · 5.07 Impact Factor
  • Luigi Sanità di Toppi, Andrew A. Meharg
    Environmental and Experimental Botany - ENVIRON EXP BOT. 01/2011; 72(1):1-2.
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    ABSTRACT: Ectomycorrhizal fungi are thought to enhance mineral nutrition of their host plants and to confer increased tolerance toward toxic metals. However, a global view of metal homeostasis-related genes and pathways in these organisms is still lacking. Building upon the genome sequence of Tuber melanosporum and on transcriptome analyses, we set out to systematically identify metal homeostasis-related genes in this plant-symbiotic ascomycete. Candidate gene products (101) were subdivided into three major functional classes: (i) metal transport (58); (ii) oxidative stress defence (32); (iii) metal detoxification (11). The latter class includes a small-size metallothionein (TmelMT) that was functionally validated in yeast, and phytochelatin synthase (TmelPCS), the first enzyme of this kind to be described in filamentous ascomycetes. Recombinant TmelPCS was shown to support GSH-dependent, metal-activated phytochelatin synthesis in vitro and to afford increased Cd/Cu tolerance to metal hypersensitive yeast strains. Metal transporters, especially those related to Cu and Zn trafficking, displayed the highest expression levels in mycorrhizae, suggesting extensive translocation of both metals to root cells as well as to fungal metalloenzymes (e.g., laccase) that are strongly upregulated in symbiotic hyphae.
    Fungal Genetics and Biology 11/2010; 48(6):573-84. · 3.26 Impact Factor
  • L Elviri, F Speroni, M Careri, A Mangia, L Sanità di Toppi, M Zottini
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    ABSTRACT: Reversed-phase liquid chromatography (RPLC) and electrospray (ESI)-linear ion trap (LIT) mass spectrometry was applied to the direct characterization of in vivo S-nitrosylated (SNO) phytochelatins (PCs) expressed in cadmium-stressed Arabidopsis thaliana cells. Cys-nitrosylation is under discussion as in vivo redox-based post-translational modification of proteins and peptides in plants in which the -NO group is involved as signal molecule in different biological functions. The gas-phase ion chemistry of in vivo and in vitro generated SNO-PC(s) was compared with the aim of evaluating NO binding stability and improving MS knowledge about peptide nitrosation. Using RPLC separation and ESI-LIT-MS, mono-nitrosylated PCs were identified in in vivo cadmium treated A. thaliana cells without derivatization. The in vivo binding of the NO group to PC(2), PC(3) and PC(4) resulted to occur selectively on only one cystein residue. The fragmentation pathway energies of the in vitro GSNO-generated NO-PCs with respect to the in vivo NO-PCs were investigated, suggesting the presence of a different internal stability for these molecules. By carrying out MS(2) experiments on these quasi-symmetric peptides, the different stability degree of the NO group was demonstrated to be correlated with the PC chain length. In addition, the data obtained highlight a putative role of the adjacent Glu/Cys motif in the gas-phase stability of the NO-containing molecule.
    Journal of Chromatography A 02/2010; 1217(25):4120-6. · 4.61 Impact Factor
  • Tanja Mrak, Zvonka Jeran, Franc Batic, Luigi Sanità di Toppi
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    ABSTRACT: Thalli of epiphytic lichen Hypogymnia physodes (L.) Nyl. and terricolous Cladonia furcata (Huds.) Schrad., collected from an area with background arsenic concentrations, were exposed to 0, 0.1, 1 and 10 microg mL(-1) arsenate (As(V)) solutions for 24 h. After exposure they were kept in the metabolically active state for 0, 24 and 48 h in a growth chamber. In the freeze dried samples glutathione (GSH), glutathione disulphide (GSSG), cysteine (Cys) and cystine were analysed and induction of phytochelatin (PC) synthesis measured by reversed-phase high-performance liquid chromatography in combination with fluorescence detection or UV spectrometry. Total arsenic content in thalli was measured by instrumental neutron activation analysis (INAA). In H. physodes, which contained higher amounts of arsenic compared to C. furcata, total glutathione content significantly decreased in samples exposed to 10 microg mL(-1) As(V), whereas in C. furcata a significant increase was observed. In both species PC synthesis was induced in thalli exposed to 10 microg mL(-1).
    Biology of Metals 11/2009; 23(2):207-19. · 3.17 Impact Factor
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    ABSTRACT: Exposure to cadmium (Cd(2+)) can result in cell death, but the molecular mechanisms of Cd(2+) cytotoxicity in plants are not fully understood. Here, we show that Arabidopsis (Arabidopsis thaliana) cell suspension cultures underwent a process of programmed cell death when exposed to 100 and 150 microm CdCl(2) and that this process resembled an accelerated senescence, as suggested by the expression of the marker senescence-associated gene12 (SAG12). CdCl(2) treatment was accompanied by a rapid increase in nitric oxide (NO) and phytochelatin synthesis, which continued to be high as long as cells remained viable. Hydrogen peroxide production was a later event and preceded the rise of cell death by about 24 h. Inhibition of NO synthesis by N(G)-monomethyl-arginine monoacetate resulted in partial prevention of hydrogen peroxide increase, SAG12 expression, and mortality, indicating that NO is actually required for Cd(2+)-induced cell death. NO also modulated the extent of phytochelatin content, and possibly their function, by S-nitrosylation. These results shed light on the signaling events controlling Cd(2+) cytotoxicity in plants.
    Plant physiology 04/2009; 150(1):217-28. · 6.56 Impact Factor

Publication Stats

645 Citations
119.38 Total Impact Points

Institutions

  • 2002–2012
    • Università degli studi di Parma
      Parma, Emilia-Romagna, Italy
  • 2011
    • University of Aberdeen
      • Institute of Biological and Environmental Sciences
      Aberdeen, SCT, United Kingdom
  • 2009
    • Jožef Stefan Institute
      • Department of Environmental Sciences
      Ljubljana, Ljubljana, Slovenia
  • 2006
    • Pavol Jozef Šafárik University in Košice
      Kassa, Košický, Slovakia
  • 1997–2005
    • Università di Pisa
      Pisa, Tuscany, Italy
  • 1998–1999
    • University of Florence
      Florens, Tuscany, Italy