title: Tungsten affects the cortical microtubules of Pisum sativum root cells: experiments on tungsten-molybdenum antagonism.
abstract: Tungsten (W) is increasingly shown to be toxic to various organisms, including plants. Apart from inactivation of molybdo-enzymes, other potential targets of W toxicity in plants, especially at the cellular level, have not yet been revealed. In the present study, the effect of W on the cortical microtubule array of interphase root tip cells was investigated, in combination with the possible antagonism of W for the pathway of molybdenum (Mo). Pisum sativum seedlings were treated with W, Mo or a combination of the two, and cortical microtubules were examined using tubulin immunofluorescnce and TEM. Treatments with anti-microtubule (oryzalin, colchicine and taxol) or anti-actomyosin (cytochalasin D, BDM or ML-7) drugs and W were also performed. W-affected cortical microtubules were low in number, short, not uniformly arranged and were resistant to anti-microtubule drugs. Cells pre-treated with oryzalin or colchicine and then treated with W displayed W-affected microtubules, while cortical microtubules pre-stabilized with taxol were resistant to W. Treatment with Mo and anti-actomyosin drugs prevented W from affecting cortical microtubules. Cortical microtubule recovery after W treatment was faster in Mo solution than in water. The results indicate that cortical microtubules of plant cells are indirectly affected by W, most probably through a mechanism depending on the in vivo antagonism of W for the Mo-binding site of Cnx1 protein.
authors.affiliation: Department of Botany, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: I-D S
authors.initials: ID
authors.lastname: Adamakis
authors.forename: E
authors.initials: E
authors.lastname: Panteris
authors.forename: E P
authors.initials: EP
authors.lastname: Eleftheriou
mesh_terms: D018519:Meristem / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000187:drug effects* / Q000648:ultrastructure; D008982:Molybdenum / Q000494:pharmacology; D018532:Pisum sativum / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects*; D050257:Tubulin Modulators / Q000494:pharmacology; D014414:Tungsten / Q000494:pharmacology*; D017973:Tungsten Compounds / Q000494:pharmacology
chemical_list: D050257:Tubulin Modulators; D017973:Tungsten Compounds; C044659:molybdate; D008982:Molybdenum; C045951:tungstate; D014414:Tungsten