Siderophore-mediated upregulation of Arabidopsis ferritin expression in response to Erwinia chrysanthemi infection
Article first published online: 22 JUN 2005
The Plant Journal
Volume 43, Issue 2, pages 262–272, July 2005
How to Cite
Dellagi, A., Rigault, M., Segond, D., Roux, C., Kraepiel, Y., Cellier, F., Briat, J.-F., Gaymard, F. and Expert, D. (2005), Siderophore-mediated upregulation of Arabidopsis ferritin expression in response to Erwinia chrysanthemi infection. The Plant Journal, 43: 262–272. doi: 10.1111/j.1365-313X.2005.02451.x
- Issue published online: 22 JUN 2005
- Article first published online: 22 JUN 2005
- Received 23 January 2005; revised 8 April 2005; accepted 5 May 2005.
- Erwinia chrysanthemi;
- nitric oxide;
- plant defense
Ferritins are multimeric iron storage proteins encoded by a four-member gene family in Arabidopsis (AtFer1–4). To investigate whether iron sequestration in ferritins is a part of an iron-withholding defense system induced in response to bacterial invasion, we used Arabidopsis thaliana as a susceptible host for the pathogenic bacterium Erwinia chrysanthemi. In this study, we used a T-DNA insertion mutant line to show that the lack of a functional AtFer1 gene resulted in an enhanced susceptibility of Arabidopsis plants to E. chrysanthemi. We found that the AtFer1 gene is upregulated during infection, with a biphasic accumulation of the transcript at critical time points 0.5 and 24 h post-infection (p.i.). The activation of AtFer1 expression observed at 24 h p.i. was independent of the iron-dependent regulatory sequence (IDRS) known to mediate the transcriptional response of the AtFer1 gene to iron excess and to nitric oxide. Upregulation of AtFer1 gene expression was compromised after inoculation with an E. chrysanthemi siderophore null mutant. Infiltration of the purified siderophores chrysobactin and desferrioxamine strongly increased AtFer1 transcript abundance and it did not occur with the iron-loaded forms of these siderophores. We found that neither oxidative stress nor nitric oxide was involved in the plant response to chrysobactin. Our data show that ferritin accumulation during infection of Arabidopsis by E. chrysanthemi is a basal defense mechanism which is mainly activated by bacterial siderophores. The potential role of siderophores in this process is discussed.