Journal Article

Cadmium Toxicity Induced Changes in Nitrogen Management in <i>Lycopersicon esculentum</i> Leading to a Metabolic Safeguard Through an Amino Acid Storage Strategy

Chiraz Chaffei, Karine Pageau, Akira Suzuki, Houda Gouia, Mohamed Habib Ghorbel and Céline Masclaux-Daubresse

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 45, issue 11, pages 1681-1693
Published in print November 2004 | ISSN: 0032-0781
Published online November 2004 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pch192
Cadmium Toxicity Induced Changes in Nitrogen Management in Lycopersicon esculentum Leading to a Metabolic Safeguard Through an Amino Acid Storage Strategy

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Tomato (Lycopersicon esculentum) seedlings were grown in the presence of cadmium. After 1 week of Cd treatment, a sharp decline in biomass accumulation in the leaves and roots was observed, together with a decrease in the rate of photosynthetic activity due to both Rubisco and chlorophyll degradation and stomata closure. Cadmium induced a significant decrease in nitrate content and inhibition of the activities of nitrate reductase, nitrite reductase, glutamine synthetase (GS) and ferredoxin-glutamate synthase. An increase in NADH-glutamate synthase and NADH-glutamate dehydrogenase activity was observed in parallel. The accumulation of ammonium into the tissues of treated plants was accompanied by a loss of total protein and the accumulation of amino acids. Gln represented the major amino acid transported through xylem sap of Cd-treated and control plants. Cadmium treatment increased the total amino acid content in the phloem, maintaining Gln/Glu ratios. Western and Northern blot analysis of Cd-treated plants showed a decrease in chloroplastic GS protein and mRNA and an increase in cytosolic GS and glutamate dehydrogenase transcripts and proteins. An increase in asparagine synthetase mRNA was observed in roots, in parallel with a strong increase in asparagine. Taken together, these results suggest that the plant response to Cd stress involved newly induced enzymes dedicated to coordinated leaf nitrogen remobilization and root nitrogen storage.

Keywords: Keywords: Cadmium stress — Lycopersicon esculentum — Nitrogen — Senescence.; Abbreviations: Cd, cadmium; Fd-GOGAT, ferredoxin-dependent glutamate synthase; GaBa, γ-amino-n-butyric acid; GDH, glutamate dehydrogenase; GS, glutamine sunthetase; GS1, cytosolic GS; GS2, chloroplastic GS; ICDH, isocitrate dehydrogenase; MDH, malate dehydrogenase; NADH-GOGAT, NADH-dependent GOGAT; NAD+-MDH, NAD+-dependent MDH; NADH-MDH, NADH-dependent MDH; NADP+-MDH, NADP+-dependent MDH; NADPH-MDH, NADPH-dependent MDH; NR, nitrate reductase; NiR, nitrite reductase.

Journal Article.  8493 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.