title: Accumulation of cytokinins in roots and their export to the shoots of durum wheat plants treated with the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP).
abstract: Cytokinin flow from roots to shoots can serve as a long-distance signal important for root-to-shoot communication. In the past, changes in cytokinin flow from roots to shoots have been mainly attributed to changes in the rate of synthesis or breakdown in the roots. The present research tested the possibility that active uptake of cytokinin by root cells may also influence its export to shoots. To this end, we collapsed the proton gradient across root membranes using the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) to inhibit secondary active uptake of exogenous and endogenous cytokinins. We report the impact of CCCP on cytokinin concentrations and delivery in xylem sap and on accumulation in shoots of 7-day-old wheat plants in the presence and absence of exogenous cytokinin applied as zeatin. Zeatin treatment increased the total accumulation of cytokinin in roots and shoots but the effect was smaller for the shoots. Immunohistochemical localization of cytokinins using zeatin-specific antibodies showed an increase in immunostaining of the cells adjacent to xylem in the roots of zeatin-treated plants. Inhibition of secondary active cytokinin uptake by CCCP application decreased cytokinin accumulation in root cells but increased both flow from the roots and accumulation in the shoots. The possible importance of secondary active uptake of cytokinins by root cells for the control of their export to the shoot is discussed.
authors.affiliation: Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia guzel@ufaras.ru.
authors.forename: Guzel R
authors.initials: GR
authors.lastname: Kudoyarova
authors.affiliation: Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia.
authors.forename: Alla V
authors.initials: AV
authors.lastname: Korobova
authors.affiliation: Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia.
authors.forename: Guzel R
authors.initials: GR
authors.lastname: Akhiyarova
authors.affiliation: Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia.
authors.forename: Tatiana N
authors.initials: TN
authors.lastname: Arkhipova
authors.affiliation: Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia.
authors.forename: Denis Yu
authors.initials: DY
authors.lastname: Zaytsev
authors.affiliation: Department of Biology, Laboratory for Plant Biochemistry and Physiology, University of Antwerpen, 2020 Antwerpen, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Prinsen
authors.affiliation: Institute of Organic Chemistry, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia.
authors.forename: Naum L
authors.initials: NL
authors.lastname: Egutkin
authors.affiliation: St Petersburg State University, Universitetskaya naberezhnaya 7/9, 199034, St Petersburg, Russia.
authors.forename: Sergey S
authors.initials: SS
authors.lastname: Medvedev
authors.affiliation: Bashkir State University, Zaki-Validi st. 32, 450074, Ufa, Russia.
authors.forename: Stanislav Yu
authors.initials: SY
authors.lastname: Veselov
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology*; D003583:Cytokinins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism*; D014908:Triticum / Q000187:drug effects* / Q000378:metabolism
chemical_list: D003583:Cytokinins; D010937:Plant Growth Regulators; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone
keywords: Cytokinin; Triticum durum; protonophore; root-to-shoot communication; secondary active uptake; xylem transport; zeatin.