Copper exposure interferes with the regulation of the uptake, distribution and metabolism of sulfate in Chinese cabbage

Muhammad Shahbaz, M.-H. Tseng, C. Elisabeth E. Stuiver, Aleksandra Koralewska, Freek S. Posthumus, Jan Henk Venema, Saroj Parmar, Henk Schat, Malcolm J. Hawkesford, Luit J. De Kok*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

35 Citations (Scopus)

Abstract

Exposure of Chinese cabbage (Brassica pekinensis) to enhanced Cu(2+) concentrations (1-10 mu M) resulted in leaf chlorosis, a loss of photosynthetic capacity and lower biomass production at >= 5 mu M. The decrease in pigment content was likely not the consequence of degradation, but due to hindered chloroplast development upon Cu exposure. The Cu content of the root increased with the Cu(2+) concentration (up to 40-fold), though only a minor proportion (4%) was transferred to the shoot. The nitrate uptake by the root was substantially reduced at >= 5 mu M Cu(2+). The nitrogen content of the root was affected little at lower Cu(2+) levels, whereas that in the shoot was decreased at >= 5 mu M Cu(2+). Cu affected the uptake, distribution and metabolism of sulfate in Chinese cabbage. The total sulfur content of the shoot was increased at >= 2 mu M Cu(2+), which could be attributed mainly to an increase in sulfate content. Moreover, there was a strong increase in water-soluble non-protein thiol content in the root and, to a lesser extent, in the shoot at >= 1 mu M, which could only partially be ascribed to a Cu-induced enhancement of the phytochelatin content. The nitrate uptake by the root was substantially reduced at >= 5 mu M Cu(2+), coinciding with a decrease in biomass production. However, the activity of the sulfate transporters in the root was slightly enhanced at 2 and 5 mu M Cu(2+), accompanied by enhanced expression of the Group 1 high affinity transporter Sultr1;2, and the Group 4 transporters Sultr4;1 and Sultr4;2. In the shoot, there was an induction of expression of Sultr4;2 at 5 and 10 mu M Cu(2+). The expression of APS reductase was affected little in the root and shoot up to 10 mu M Cu(2+). The upregulation of the sulfate transporters may be due not only to greater sulfur demand at higher Cu levels, but also the consequence of interference by Cu with the signal transduction pathway regulating the expression and activity of the sulfate transporters. (C) 2009 Elsevier GmbH. All rights reserved.

Original languageEnglish
Pages (from-to)438-446
Number of pages9
JournalJournal of Plant Physiology
Volume167
Issue number6
DOIs
Publication statusPublished - 2010

Keywords

  • Glutathione
  • Heavy metals
  • Phytochelatins
  • Sulfate transporters
  • Sulfate uptake
  • VULGARE SUBSP-HIRTUM
  • BRASSICA-OLERACEA
  • ATMOSPHERIC H2S
  • IN-VIVO
  • SULFUR METABOLISM
  • OXIDATIVE STRESS
  • SILENE-CUCUBALUS
  • APS REDUCTASE
  • HEAVY-METALS
  • CURLY KALE

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