Medicago truncatula shows a high level of specificity when interacting with its symbiotic partner Sinorhizobium meliloti. This specificity is mainly manifested at the nitrogen-fixing stage of nodule development, such that a particular bacterial strain forms nitrogen-fixing nodules (NodiFix) on one plant genotype but ineffective nodules (NodIFix ) on another. Recent studies have just begun to reveal the underlying molecular mechanisms that control this specificity. The S. meliloti strain A145 induces the formation of Fix nodules on the accession DZA315.16 but Fix nodules on Jemalong A17. A previous study reported that the formation of Fix nodules on Jemalong A17 by S. meliloti A145 was conditioned by a single recessive allele named Mtsym6. Here we demonstrate that the specificity associated with S. meliloti A145 is controlled by multiple genes in M. truncatula, including NFS1 and NFS2 that encode nodule-specific cysteinerich (NCR) peptides. The two NCR peptides acted dominantly to block rather than promote nitrogen fixation by S. meliloti A145. These two NCR peptides are the same ones that negatively regulate nitrogen-fixing symbiosis associated with S. meliloti Rm41.
|Number of pages
|Molecular Plant-Microbe Interactions
|Published - Feb 2018
Bibliographical noteFunding Information:
We would like to thank Jean-Marie Prosperi (Institut National de la Recherche Agronomique), Laurent Gentzbittel (Université de Toulouse), Peter Mergaert (Université Paris-Sud), Sharon Long (Stanford University), Clay Fuqua (Indiana University), and Qijun Chen (China Agricultural University) for providing materials for this study. This work was supported by the USDA/NIFA’s Agriculture and Food Research Initiative (grant number 2014-67013-21573 to H.Z.), the Kentucky Science and Engineer Foundation (grant number 2615-RDE-015 to H.Z.), and the Hungarian National Research Fund/National Research, Development and Innovation Office (OTKA) (grant number 120122/120300 to A.K). Confocal microscopy work was supported by the US National Science Foundation under Cooperative Agreement No. 1355438.
© 2018 The American Phytopathological Society .
ASJC Scopus subject areas
- Agronomy and Crop Science