Microsymbiont discrimination mediated by a host-secreted peptide in Medicago truncatula

The legume–rhizobial symbiosis results in the formation of root nodules that provide an ecological niche for nitrogen-fixing bacteria. However, plant–bacteria genotypic interactions can lead to wide variation in nitrogen fixation efficiency, and it is not uncommon that a bacterial strain forms functional (Fix+) nodules on one plant genotype but nonfunctional (Fix−) nodules on another. Host genetic control of this specificity is unknown. We herein report the cloning of the Medicago truncatula NFS1 gene that regulates the fixation-level incompatibility with the microsymbiont Sinorhizobium meliloti Rm41. We show that NFS1 encodes a nodule-specific cysteine-rich (NCR) peptide. In contrast to the known role of NCR peptides as effectors of endosymbionts’ differentiation to nitrogen-fixing bacteroids, we demonstrate that specific NCRs control discrimination against incompatible microsymbionts. NFS1 provokes bacterial cell death and early nodule senescence in an allele-specific and rhizobial strain-specific manner, and its function is dependent on host genetic background.

Bibliographic Details

Main Authors:	Yang, Shengming, Wang, Qi, Fedorova, Elena, Liu, Jinge, Qin, Qiulin, Zheng, Qiaolin, Price, Paul A., Pan, Huairong, Wang, Dong, Griffitts, Joel S., Bisseling, Ton, Zhu, Hongyan
Format:	Article/Letter to editor biblioteca
Language:	English
Subjects:	Legumes, NCR peptides, Nitrogen fixation specificity, Nodulation, Symbiosis persistence,
Online Access:	https://research.wur.nl/en/publications/microsymbiont-discrimination-mediated-by-a-host-secreted-peptide-
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