Uptake and apoplastic retention of EDTA- and phytosiderophore-chelated chromium(III) in maize

Erenoglu B. E., Patra H. K., Khodr H., Roemheld V., von Wiren N.

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, vol.170, no.6, pp.788-795, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 170 Issue: 6
  • Publication Date: 2007
  • Doi Number: 10.1002/jpln.200700068
  • Journal Name: JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.788-795
  • Keywords: synthetic chelate, ZmYS1, Cr(III) uptake, maize roots, phytoremediation, III-IRON INTERACTION, HORDEUM-VULGARE-L, BEAN-PLANTS, ZEA-MAYS, TRANSPORT, ROOTS, SEEDLINGS, TRANSLOCATION, MOBILIZATION, SUFFICIENT
  • Çukurova University Affiliated: Yes

Abstract

Increasing the mobilization and root uptake of chromium (Cr) by synthetic and plant-borne chelators might be relevant for the design of phytoremediation strategies on Cr-contaminated sites. Short-term uptake studies in maize roots supplied with 51CrCl3 or 51Cr(III)-EDTA led to higher apoplastic Cr contents in plant roots supplied with 51CrCl3 and in Fe-sufficient plants relative to Fe-deficient plants, indicating that Fe stimulated co-precipitation of Cr. Concentration-dependent retention of Cr in a methanol:chloroform-treated cell-wall fraction was still saturable and in agreement with the predicted tendency of Cr(III) to precipitate as Cr(OH)3. To investigate a possible stimulation of Cr(III) uptake by phytosiderophores, Fe-deficient maize roots were exposed for 6 d to Cr(III)-EDTA or Cr(III)-DMA (2'-deoxymugineic acid). Relative to plants without Cr supply, the supply of both chelated Cr species in a subtoxic concentration of 1 µM resulted in alleviation of Fe deficiency–induced chlorosis and higher Cr accumulation. Long-term Cr accumulation from Cr(III)-DMA was similar to that from Cr(III)-EDTA, and Cr uptake from both chelates was not altered in the maize mutant ys1, which is defective in metal-phytosiderophore uptake. We therefore conclude that phytosiderophores increase Cr solubility similar to synthetic chelators like EDTA, but do not additionally contribute to Cr(III) uptake from Cr-contaminated sites.

Increasing the mobilization and root uptake of chromium (Cr) by synthetic and plant-borne chelators might be relevant for the design of phytoremediation strategies on Cr-contaminated sites. Short-term uptake studies in maize roots supplied with (CrCl3)-Cr-51 or Cr-51(III)-EDTA led to higher apoplastic Cr contents in plant roots supplied with (CrCl3)-Cr-51 and in Fe-sufficient plants relative to Fe-deficient plants, indicating that Fe stimulated co-precipitation of Cr. Concentration-dependent retention of Cr in a methanol:chloroform-treated cell-wall fraction was still saturable and in agreement with the predicted tendency of Cr(III) to precipitate as Cr(OH)(3) To investigate a possible stimulation of Cr(III) uptake by phytosiderophores, Fe-deficient maize roots were exposed for 6 d to Cr(III)-EDTA or Cr(III)-DMA (2'-deoxymugineic acid). Relative to plants without Cr supply, the supply of both chelated Cr species in a subtoxic concentration of 1 mu M resulted in alleviation of Fe deficiency-induced chlorosis and higher Cr accumulation. Long-term Cr accumulation from Cr(III)-DMA was similar to that from Cr(III)-EDTA, and Cr uptake from both chelates was not altered in the maize mutant ys1, which is defective in metal-phytosiderophore uptake. We therefore conclude that phytosiderophores increase Cr solubility similar to synthetic chelators like EDTA, but do not additionally contribute to Cr(III) uptake from Cr-contaminated sites.