Skip to main content
ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Improvement Research » Research » Publications at this Location » Publication #414176
Research Project: Improvement of Disease and Pest Resistance in Barley, Durum, Oat, and Wheat Using Genetics and Genomics

Location: Cereal Crops Improvement Research

Title: Species-specific microsymbiont discrimination mediated by a Medicago receptor kinase

Author
item YU, XIAOCHENG - University Of Kentucky
item LIU, JINGE - University Of Kentucky
item QIN, QIULIN - University Of Kentucky
item ZRIBI, IKRAM - Hungarian Academy Of Sciences
item YU, JINGYIN - Cornell University
item Yang, Shengming
item Dinkins, Randy
item FEI, ZHANGJUN - Cornell University
item KERESZT, ATTILA - Hungarian Academy Of Sciences
item ZHU, HONGYAN - University Of Kentucky

Submitted to: Science Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2024
Publication Date: 7/31/2024
Citation: Yu, X., Liu, J., Qin, Q., Zribi, I., Yu, J., Yang, S., Dinkins, R.D., Fei, Z., Kereszt, A., Zhu, H. 2024. Species-specific microsymbiont discrimination mediated by a Medicago receptor kinase. Science Advances. 10(31). https://doi.org/10.1126/sciadv.adp6436.
DOI: https://doi.org/10.1126/sciadv.adp6436

Interpretive Summary: Rhizobia are soil-inhabiting bacteria that form specialized structures, called nodules, on the roots of legume plants. Within the nodules, rhizobia can convert atmospheric nitrogen into ammonia that can be utilized by legumes. However, how the symbiotic partners recognize and communicate between each other is less understood. In this study we have cloned and characterized a new receptor gene in the model legume Medicago truncatula, a close relative of alfalfa. When this receptor is activated by rhizobia strains carrying a specific protein in the cell wall, plant blocks the rhizobia in, and no nodule is formed. Therefore, our discovery reveals a previously undescribed mechanism regulating the recognition between legume and rhizobia, and it provides knowledge and gene targets for both plant geneticists and microbiologists to broaden the host range for rhizobia.

Technical Abstract: Host range specificity is a prominent feature of the legume-rhizobial symbiosis. Sinorhizobium meliloti and Sinorhizobium medicae are two closely related species that engage in root nodule symbiosis with legume plants of the Medicago genus, but certain Medicago species exhibit selectivity in their interaction with the two rhizobial species. We have identified a Medicago receptor-like kinase, which can discriminate between the two bacterial species, acting as a genetic barrier against infection by most S. medicae strains. Activation of this receptor-mediated nodulation restriction requires a bacterial gene that encodes a glycine-rich octapeptide repeat protein with distinct variants capable of distinguishing S. medicae from S. meliloti. This study sheds light on the coevolution of host plants and rhizobia, shaping symbiotic selectivity in their respective ecological niches.