Early cadmium-induced effects on reactive oxygen species production, cell viability and membrane electrical potential in grapevine roots

Cadmium (Cd) is one of the most worldwide concerned metal pollutants. It is able to induce reactive oxygen species production through indirect mechanisms causing oxidative stress. Vitis vinifera roots were treated with 100 μM Cd for 0-180 min or 20-100 μM Cd for 24 h. Fluorescence confocal microscopy showed elevated hydrogen peroxide and superoxide levels in the apical root segments. Two phases (after 30 min and 24 h) of the superoxide raised levels were observed. This was accompanied by the decrease in root cell viability. Cd in concentrations between 0.005-10 mM induced significant, but different changes in membrane electrical potential (EM) of the root epidermal cells. The low concentrations of Cd (0.005-0.01 mM) caused transient EM hyperpolarization followed by depolarization, whereas by higher concentrations (0.05-5.0 mM) EM was depolarized. In any case, the depolarization or hyperpolarization were only transient up to 5 mM Cd concentration indicating that the plasma membrane function was not irreversibly destroyed. Hyperpolarization of EM induced by fusicoccin (FC) was completely suppressed only in the presence of 10 mM Cd pointing to the inhibition of H+-ATPase. The results suggest that the Cd interactions, depending on cellular development, result in activation of a complex of various mechanisms such as peroxide and hydrogen peroxide production, which in turn may be a more probable reason for the root cell responses to Cd toxicity than the transient EM changes

Dissimilar responses of membrane potential (EM), permeability properties and respiration to cadmium and nickel in maize root cells

The short-term treatment with Cd2+ and Ni2+ triggered transient depolarization of transplasma membrane potential (EM) in the outer cortical root cells of two maize cultivars (cv. Premia and cv. Blitz), however, both metals changed the EM in a quantitatively different way. The magnitude and duration of EM depolarization were concentration dependent and were greater in the metal susceptible cv. Blitz. The highest EM depolarization was recorded with simultaneous application of Cd2+ + Ni2+ in both maize cultivars. The EM depolarization induced by Cd2+ or Cd2+ + Ni2+ but not Ni2+ alone was accompanied with a tremendous increase of membrane conductivity, but it was not accompanied with the effect of heavy metals (HM) on respiration. Simultaneous application of fusiccocin (FC) with Cd2+ or Cd2+ + Ni2+ during the EM depolarization, inability of FC to stop the depolarization by FC-enhanced proton extrusion and rapid restoration of EM, suggested a transient inhibition of the plasma membrane H+-ATPase by these toxic metals. Our data support the opinion that differences in the effects of the studied ions were not the result of their direct action on PM, but rather of their different influence on intracellular processes within root cells

An urban Blitz with a twist: rapid biodiversity assessment using aquatic environmental DNA

As global biodiversity declines, there is an increasing need to create an educated and engaged society. Having people of all ages participate in measuring biodiversity where they live helps to create awareness. Recently, the use of environmental DNA (eDNA) for biodiversity surveys has gained momentum. Here, we explore whether sampling eDNA and sequencing it can be used as a means of rapidly surveying urban biodiversity for educational purposes. We sampled 2 × 1 L of water from each of 15 locations in the city of Trondheim, Norway, including a variety of freshwater, marine, and brackish habitats. DNA was extracted, amplified in triplicate targeting the barcoding fragment of COI gene, and sequenced. The obtained data were analyzed on the novel mBRAVE platform, an online open‐access software and computing resource. The water samples were collected in 2 days by two people, and the laboratory analysis was completed in 5 days by one person. Overall, we detected the presence of 506 BINs identified as belonging to 435 taxa, representing at least 265 putative species. On average, only 5.4% of the taxa were shared among six replicates per site. Based on the observed diversity, three distinct clusters were detected and related to the geographic distribution of sites. There were some taxa shared between the habitats, with a substantial presence of terrestrial biota. Here we propose a new form of BioBlitz, where with noninvasive sampling effort combined with swift processing and straightforward online analyses, hundreds of species can be detected. Thus, using eDNA analysis of water is useful for rapid biodiversity surveys and valuable for educational purposes. We show that rapid eDNA surveys, combined with openly available services and software, can be used as an educational tool to raise awareness about the importance of biodiversity.© 2020 The Authors. Environmental DNA published by John Wiley & Sons Ltd This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. The attached file is the published pdf

DNA barcode reference libraries for the monitoring of aquatic biota in Europe: Gap-analysis and recommendations for future work

Effective identification of species using short DNA fragments (DNA barcoding and DNA metabarcoding) requires reliable sequence reference libraries of known taxa. Both taxonomically comprehensive coverage and content quality are important for sufficient accuracy. For aquatic ecosystems in Europe, reliable barcode reference libraries are particularly important if molecular identification tools are to be implemented in biomonitoring and reports in the context of the EU Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD). We analysed gaps in the two most important reference databases, Barcode of Life Data Systems (BOLD) and NCBI GenBank, with a focus on the taxa most frequently used in WFD and MSFD. Our analyses show that coverage varies strongly among taxonomic groups, and among geographic regions. In general, groups that were actively targeted in barcode projects (e.g. fish, true bugs, caddisflies and vascular plants) are well represented in the barcode libraries, while others have fewer records (e.g. marine molluscs, ascidians, and freshwater diatoms). We also found that species monitored in several countries often are represented by barcodes in reference libraries, while species monitored in a single country frequently lack sequence records. A large proportion of species (up to 50%) in several taxonomic groups are only represented by private data in BOLD. Our results have implications for the future strategy to fill existing gaps in barcode libraries, especially if DNA metabarcoding is to be used in the monitoring of European aquatic biota under the WFD and MSFD. For example, missing species relevant to monitoring in multiple countries should be prioritized for future collaborative programs. We also discuss why a strategy for quality control and quality assurance of barcode reference libraries is needed and recommend future steps to ensure full utilisation of metabarcoding in aquatic biomonitoring.This paper is a deliverable of the European Cooperation in Science and Technology (COST) Action DNAqua-Net (CA15219) Working Group 1, led by Torbjørn Ekrem and Fedor Čiampor. Thanks to the University of Minho and University of Pécs for hosting workshops and working group meetings. We also thank staff at National Environment Agencies and others that provided national checklists of taxa used in biomonitoring, and otherwise assisted with checklist proof-reading: Jarmila Makovinská and Emília Mišíková Elexová (Slovakia); Steinar Sandøy and Dag Rosland (Norway); Mišel Jelič (Croatia); Marlen Vasquez (Cyprus); Adam Petrusek (Czech Republic); Kristel Panksep (Estonia); Panagiotis Kaspiditis (Greece); Matteo Montagna (Italy); Marija Katarzyte (Lithuania); Ana Rotter (Slovenia); Rosa Trabajo (Spain); Florian Altermatt (Switzerland); Kristian Meissner (Finland), Rigers Bakiu (Albania), Valentina Stamenkovic and Jelena Hinic (Macedonia); Patricia Mergen (Belgium); Gael Denys & the French Biodiversity Agency (France); Mary Kelly-Quinn (Ireland); Piotr Panek and Andrzej Zawal (Poland); Cesare Mario Puzzi (Italy); Carole Fitzpatrick (United Kingdom); Simon Vitecek (Austria); Ana Filipa Filipe (Portugal); Peter Anton Stæhr & Anne Winding (Denmark); Michael Monaghan (Germany); Alain Dohet, Lionel L'Hoste, Nora Welschbillig & Luc Ector (Luxembourg), Lujza Keresztes, (Romania). The authors also want to thank Dirk Steinke for providing the original European ERMS list for marine taxa and Florian Malard for comments on the manuscript. The preparation of the AMBI checklist was carried out in the scope of a Short-term Scientific Mission (ECOST-STSM-CA15219-150217- 082111) granted to SD visiting AZTI, Spain. ZC was supported by grants EFOP-3.6.1.-16-2016-00004 and 20765-3/2018/FEKUTSTRAT. TE was supported by the NorBOL-grant (226134/F50) from the Research Coun cil of Norway. BR, FL and MFG contributed through support from the GBOL project, which is generously funded by the German Federal Min istry of Education and Research (FKZ 01LI1101 and 01LI1501). MG contributed through support of the Polish National Science Centre, grants N N303 5794 39 and 2014/15/B/NZ8/00266. SF was funded by the project PORBIOTA - Portuguese E-Infrastructure for Information and Research on Biodiversity (POCI-01-0145-FEDER-022127), supported by Operational Thematic Program for Competitiveness and Internationalization (POCI), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (FEDER)

Session 17 Ecophysiology

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Is fusaproliferin associated with disease symptoms in maize plants?

The possible role of fusariotoxin-fusaproliferin in Fusarium disease was investigated with respect to ultrastructure responses in the cells of maize leaves. The seedlings of resistant (Lucia) and susceptible (Pavla) maize cultivars were grown on two fusaproliferin concentrations (5 and 35 µg/mL −1 ). Only the higher concentration caused appearance of visible symptoms on the leaves. Structural changes of chloroplasts such as dilatation of grana thylakoids in the mesophyll chloroplasts, thylakoid disorganization, and an increased number of osmiophilic globules (plastoglobuli) in the stroma were observed in mesophyll and bundle sheath chloroplasts of both cultivars. The higher toxin concentration sporadically induced severe damage to the outer chloroplast membrane. The extent of ultrastructure disturbances depended on toxin concentration and it was greater in the susceptible cultivar Pavla. Fusaproliferin may be involved in Fusarium pathogenesis as a virulence factor or, by enhancing activity of some other toxins that might be concomitantly present in the diseased plants

Tissue organization and cell ultrastructure in the roots of three Arabidopsis species grown at different zinc concentrations

The model plant Arabidopsis thaliana is known to be heavy metal-sensitive in contrast to its relative species A. arenosa and A. halleri classified as pseudometallophytes. Quantitative differences in primary root anatomy previously found between A. thaliana and the non-metallicolous (NM) and metallicolous (M) populations of the non-model Arabidopsis species necessitated further research at cellular and ultrastructural levels. Seedlings of A. thaliana, ecotype Columbia and a natural population Ratkovo, the NM and M populations of A. arenosa and A. halleri were grown on agar medium containing 10 μM (control) and 1000 μM Zn2+ for 5 days. Light microscopy confirmed the higher number of cells in the endodermal, cortical and epidermal layers and a higher incidence of additional cell tiers, the so-called middle cortex (MC) in the tolerant genotypes. Such differences were present in untreated plants and even more pronounced in plants exposed to excess of zinc (Zn). Electron microscopy of the root tissues at comparable distances from the root tip showed Casparian bands only in the radial cell walls of endodermis of A. halleri M population originating from severely (Cu, Cd and Pb) contaminated site. Casparian bands were not differentiated yet in the roots of the other species and populations, and they were not formed in the cell walls between endodermis and MC cells. In the apical cytoplasm of trichoblast bulges, autophagic vacuoles were found only in the sensitive A. thaliana and small vacuoles in the other genotypes. The enhanced concentration of Zn confirmed the higher metal sensitivity of the model species and did not substantially disturb the root cell ultrastructure of the tolerant Arabidopsis species