Revisiting the iron pools in cucumber roots: identification and localization

Krisztina Kovács, Jiří Pechoušek, Libor Machala, Radek Zbořil, Z. Klencsár, Ádám Solti, Brigitta Tóth, Brigitta Müller, Hong Diep Pham, Zoltán Kristóf, F. Fodor

Research output: Article

8 Citations (Scopus)

Abstract

Main conclusion: Fe deficiency responses in Strategy I causes a shift from the formation of partially removable hydrous ferric oxide on the root surface to the accumulation of Fe-citrate in the xylem.Iron may accumulate in various chemical forms during its uptake and assimilation in roots. The permanent and transient Fe microenvironments formed during these processes in cucumber which takes up Fe in a reduction based process (Strategy I) have been investigated. The identification of Fe microenvironments was carried out with 57Fe Mössbauer spectroscopy and immunoblotting, whereas reductive washing and high-resolution microscopy was applied for the localization. In plants supplied with 57FeIII-citrate, a transient presence of Fe-carboxylates in removable forms and the accumulation of partly removable, amorphous hydrous ferric oxide/hydroxyde have been identified in the apoplast and on the root surface, respectively. The latter may at least partly be the consequence of bacterial activity at the root surface. Ferritin accumulation did not occur at optimal Fe supply. Under Fe deficiency, highly soluble ferrous hexaaqua complex is transiently formed along with the accumulation of Fe-carboxylates, likely Fe-citrate. As 57Fe-citrate is non-removable from the root samples of Fe deficient plants, the major site of accumulation is suggested to be the root xylem. Reductive washing results in another ferrous microenvironment remaining in the root apoplast, the FeII-bipyridyl complex, which accounts for ~30 % of the total Fe content of the root samples treated for 10 min and rinsed with CaSO4 solution. When 57FeIII-EDTA or 57FeIII-EDDHA was applied as Fe-source higher soluble ferrous Fe accumulation was accompanied by a lower total Fe content, confirming that chelates are more efficient in maintaining soluble Fe in the medium while less stable natural complexes as Fe-citrate may perform better in Fe accumulation.

Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalPlanta
DOIs
Publication statusAccepted/In press - márc. 22 2016

Fingerprint

Cucumis sativus
Citric Acid
cucumbers
Iron
iron
citrates
Xylem
apoplast
2,2'-Dipyridyl
washing
xylem
Ferritins
Immunoblotting
Edetic Acid
Microscopy
Spectrum Analysis
EDTA (chelating agent)
chelates
ferritin
immunoblotting

ASJC Scopus subject areas

  • Plant Science
  • Genetics

Cite this

Revisiting the iron pools in cucumber roots : identification and localization. / Kovács, Krisztina; Pechoušek, Jiří; Machala, Libor; Zbořil, Radek; Klencsár, Z.; Solti, Ádám; Tóth, Brigitta; Müller, Brigitta; Pham, Hong Diep; Kristóf, Zoltán; Fodor, F.

In: Planta, 22.03.2016, p. 1-13.

Research output: Article

Kovács, K, Pechoušek, J, Machala, L, Zbořil, R, Klencsár, Z, Solti, Á, Tóth, B, Müller, B, Pham, HD, Kristóf, Z & Fodor, F 2016, 'Revisiting the iron pools in cucumber roots: identification and localization', Planta, pp. 1-13. https://doi.org/10.1007/s00425-016-2502-x
Kovács, Krisztina ; Pechoušek, Jiří ; Machala, Libor ; Zbořil, Radek ; Klencsár, Z. ; Solti, Ádám ; Tóth, Brigitta ; Müller, Brigitta ; Pham, Hong Diep ; Kristóf, Zoltán ; Fodor, F. / Revisiting the iron pools in cucumber roots : identification and localization. In: Planta. 2016 ; pp. 1-13.
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abstract = "Main conclusion: Fe deficiency responses in Strategy I causes a shift from the formation of partially removable hydrous ferric oxide on the root surface to the accumulation of Fe-citrate in the xylem.Iron may accumulate in various chemical forms during its uptake and assimilation in roots. The permanent and transient Fe microenvironments formed during these processes in cucumber which takes up Fe in a reduction based process (Strategy I) have been investigated. The identification of Fe microenvironments was carried out with 57Fe M{\"o}ssbauer spectroscopy and immunoblotting, whereas reductive washing and high-resolution microscopy was applied for the localization. In plants supplied with 57FeIII-citrate, a transient presence of Fe-carboxylates in removable forms and the accumulation of partly removable, amorphous hydrous ferric oxide/hydroxyde have been identified in the apoplast and on the root surface, respectively. The latter may at least partly be the consequence of bacterial activity at the root surface. Ferritin accumulation did not occur at optimal Fe supply. Under Fe deficiency, highly soluble ferrous hexaaqua complex is transiently formed along with the accumulation of Fe-carboxylates, likely Fe-citrate. As 57Fe-citrate is non-removable from the root samples of Fe deficient plants, the major site of accumulation is suggested to be the root xylem. Reductive washing results in another ferrous microenvironment remaining in the root apoplast, the FeII-bipyridyl complex, which accounts for ~30 {\%} of the total Fe content of the root samples treated for 10 min and rinsed with CaSO4 solution. When 57FeIII-EDTA or 57FeIII-EDDHA was applied as Fe-source higher soluble ferrous Fe accumulation was accompanied by a lower total Fe content, confirming that chelates are more efficient in maintaining soluble Fe in the medium while less stable natural complexes as Fe-citrate may perform better in Fe accumulation.",
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AU - Kovács, Krisztina

AU - Pechoušek, Jiří

AU - Machala, Libor

AU - Zbořil, Radek

AU - Klencsár, Z.

AU - Solti, Ádám

AU - Tóth, Brigitta

AU - Müller, Brigitta

AU - Pham, Hong Diep

AU - Kristóf, Zoltán

AU - Fodor, F.

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N2 - Main conclusion: Fe deficiency responses in Strategy I causes a shift from the formation of partially removable hydrous ferric oxide on the root surface to the accumulation of Fe-citrate in the xylem.Iron may accumulate in various chemical forms during its uptake and assimilation in roots. The permanent and transient Fe microenvironments formed during these processes in cucumber which takes up Fe in a reduction based process (Strategy I) have been investigated. The identification of Fe microenvironments was carried out with 57Fe Mössbauer spectroscopy and immunoblotting, whereas reductive washing and high-resolution microscopy was applied for the localization. In plants supplied with 57FeIII-citrate, a transient presence of Fe-carboxylates in removable forms and the accumulation of partly removable, amorphous hydrous ferric oxide/hydroxyde have been identified in the apoplast and on the root surface, respectively. The latter may at least partly be the consequence of bacterial activity at the root surface. Ferritin accumulation did not occur at optimal Fe supply. Under Fe deficiency, highly soluble ferrous hexaaqua complex is transiently formed along with the accumulation of Fe-carboxylates, likely Fe-citrate. As 57Fe-citrate is non-removable from the root samples of Fe deficient plants, the major site of accumulation is suggested to be the root xylem. Reductive washing results in another ferrous microenvironment remaining in the root apoplast, the FeII-bipyridyl complex, which accounts for ~30 % of the total Fe content of the root samples treated for 10 min and rinsed with CaSO4 solution. When 57FeIII-EDTA or 57FeIII-EDDHA was applied as Fe-source higher soluble ferrous Fe accumulation was accompanied by a lower total Fe content, confirming that chelates are more efficient in maintaining soluble Fe in the medium while less stable natural complexes as Fe-citrate may perform better in Fe accumulation.

AB - Main conclusion: Fe deficiency responses in Strategy I causes a shift from the formation of partially removable hydrous ferric oxide on the root surface to the accumulation of Fe-citrate in the xylem.Iron may accumulate in various chemical forms during its uptake and assimilation in roots. The permanent and transient Fe microenvironments formed during these processes in cucumber which takes up Fe in a reduction based process (Strategy I) have been investigated. The identification of Fe microenvironments was carried out with 57Fe Mössbauer spectroscopy and immunoblotting, whereas reductive washing and high-resolution microscopy was applied for the localization. In plants supplied with 57FeIII-citrate, a transient presence of Fe-carboxylates in removable forms and the accumulation of partly removable, amorphous hydrous ferric oxide/hydroxyde have been identified in the apoplast and on the root surface, respectively. The latter may at least partly be the consequence of bacterial activity at the root surface. Ferritin accumulation did not occur at optimal Fe supply. Under Fe deficiency, highly soluble ferrous hexaaqua complex is transiently formed along with the accumulation of Fe-carboxylates, likely Fe-citrate. As 57Fe-citrate is non-removable from the root samples of Fe deficient plants, the major site of accumulation is suggested to be the root xylem. Reductive washing results in another ferrous microenvironment remaining in the root apoplast, the FeII-bipyridyl complex, which accounts for ~30 % of the total Fe content of the root samples treated for 10 min and rinsed with CaSO4 solution. When 57FeIII-EDTA or 57FeIII-EDDHA was applied as Fe-source higher soluble ferrous Fe accumulation was accompanied by a lower total Fe content, confirming that chelates are more efficient in maintaining soluble Fe in the medium while less stable natural complexes as Fe-citrate may perform better in Fe accumulation.

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KW - Mössbauer spectroscopy

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