Skip to main content
padlock icon - secure page this page is secure

Free Content Reorganization of the alternative pathways of the Arabidopsis respiratory chain by nitrogen supply: opposing effects of ammonium and nitrate

Download Article:
 Download
(PDF 340.3 kb)
 
Summary

The mitochondrial oxidative phosphorylation system in plants possesses a variety of alternative pathways that decrease respiratory ATP production. These alternative pathways are mediated by three classes of bypass proteins: the type II NAD(P)H dehydrogenases (which circumvent complex I of the electron transport chain), the alternative oxidases (AOXs ; which circumvent complexes III and IV) and the uncoupling proteins (which circumvent ATP synthase). We have monitored the expression of all genes encoding respiratory bypass proteins in Arabidopsis thaliana growing with different sources of inorganic nitrogen (N). Resupply of nitrate (NO ) to N-limited seedling cultures caused a decrease in the transcript abundance of several type II NAD(P)H dehydrogenase and AOX genes, while resupply of ammonium (NH ) led to broad increases in expression in the same gene families. Similar results were observed upon switching between nitrate and ammonium in the absence of N stress. Nitrate signalling was found to be mediated primarily by the nitrate ion itself, whereas ammonium regulation was dependent upon assimilation and affected by changes in apoplastic pH. Corresponding alterations in alternative respiratory pathway capacities were apparent in seedlings supplied with either nitrate or ammonium as an N source and in mitochondria purified from the seedlings. Specifically, AOX capacity and protein abundance, as well as calcium-dependent external NADH oxidation, were substantially elevated after growth on ammonium. The increased capacity of respiratory bypass pathways after switching from nitrate to ammonium was correlated to an overall respiratory increase.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Keywords: NAD(P)H dehydrogenase; alternative oxidase; ammonium; nitrate; plant mitochondria; respiratory chain

Document Type: Research Article

Publication date: March 1, 2006

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more