title: Caesium inhibits the colonization of Medicago truncatula by arbuscular mycorrhizal fungi.
abstract: Contamination of soils with radioisotopes of caesium (Cs) is of concern because of their emissions of harmful β and γ radiation. Radiocaesium enters the food chain through vegetation and the intake of Cs can affect the health of organisms. Arbuscular mycorrhizal (AM) fungi form mutualistic symbioses with plants through colonization of the roots and previous studies on the influence of AM on Cs concentrations in plants have given inconsistent results. These studies did not investigate the influence of Cs on AM fungi and it is therefore not known if Cs has a direct effect on AM colonization. Here, we investigated whether Cs influences AM colonization and if this effect impacts on the influence of Rhizophagus intraradices on Cs accumulation by Medicago truncatula. M. truncatula was grown with or without R. intraradices in pots containing different concentrations of Cs. Here, we present the first evidence that colonization of plants by AM fungi can be negatively affected by increasing Cs concentrations in the soil. Mycorrhizal colonization had little effect on root or shoot Cs concentrations. In conclusion, the colonization by AM fungi is impaired by high Cs concentrations and this direct effect of soil Cs on AM colonization might explain the inconsistent results reported in literature that have shown increased, decreased or unaffected Cs concentrations in AM plants.
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK; School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK. Electronic address: lea.wiesel@hutton.ac.uk.
authors.forename: Lea
authors.initials: L
authors.lastname: Wiesel
authors.affiliation: Institute of Environmental Sciences and Malopolska Centre for Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.
authors.forename: Sergiy
authors.initials: S
authors.lastname: Dubchak
authors.affiliation: Institute of Environmental Sciences and Malopolska Centre for Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Turnau
authors.affiliation: School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Broadley
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: White
mesh_terms: D002588:Cesium Radioisotopes / Q000633:toxicity*; D055137:Glomeromycota / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects*; D046913:Medicago truncatula / Q000378:metabolism* / Q000382:microbiology / Q000528:radiation effects; D038821:Mycorrhizae / Q000254:growth & development / Q000528:radiation effects*; D012990:Soil Pollutants, Radioactive / Q000633:toxicity*
chemical_list: D002588:Cesium Radioisotopes; D012990:Soil Pollutants, Radioactive
keywords: Phytoremediation; Radiocaesium; Radiocaesium contamination; Rhizophagus intraradices; Safer crop plants