Medicago truncatula DNF2 is a PI-PLC-XD-containing protein required for bacteroid persistence and prevention of nodule early senescence and defense-like reactions
Article first published online: 27 DEC 2012
© 2012 CNRS. New Phytologist © 2012 New Phytologist Trust
Volume 197, Issue 4, pages 1250–1261, March 2013
How to Cite
Bourcy, M., Brocard, L., Pislariu, C. I., Cosson, V., Mergaert, P., Tadege, M., Mysore, K. S., Udvardi, M. K., Gourion, B. and Ratet, P. (2013), Medicago truncatula DNF2 is a PI-PLC-XD-containing protein required for bacteroid persistence and prevention of nodule early senescence and defense-like reactions. New Phytologist, 197: 1250–1261. doi: 10.1111/nph.12091
- Issue published online: 4 FEB 2013
- Article first published online: 27 DEC 2012
- Manuscript Accepted: 6 NOV 2012
- Manuscript Received: 3 SEP 2012
- National Science Foundation Plant Genome Research Program. Grant Number: DBI-0703285
- The Samuel Roberts Noble Foundation
- defense-like reactions;
- insertion mutant;
- nitrogen fixation;
- Medicago truncatula and Sinorhizobium meliloti form a symbiotic association resulting in the formation of nitrogen-fixing nodules. Nodule cells contain large numbers of bacteroids which are differentiated, nitrogen-fixing forms of the symbiotic bacteria. In the nodules, symbiotic plant cells home and maintain hundreds of viable bacteria. In order to better understand the molecular mechanism sustaining the phenomenon, we searched for new plant genes required for effective symbiosis.
- We used a combination of forward and reverse genetics approaches to identify a gene required for nitrogen fixation, and we used cell and molecular biology to characterize the mutant phenotype and to gain an insight into gene function.
- The symbiotic gene DNF2 encodes a putative phosphatidylinositol phospholipase C-like protein. Nodules formed by the mutant contain a zone of infected cells reduced to a few cell layers. In this zone, bacteria do not differentiate properly into bacteroids. Furthermore, mutant nodules senesce rapidly and exhibit defense-like reactions.
- This atypical phenotype amongst Fix− mutants unravels dnf2 as a new actor of bacteroid persistence inside symbiotic plant cells.