Host-secreted antimicrobial peptide enforces symbiotic selectivity in Medicago truncatula.

نویسندگان

  • Qi Wang
  • Shengming Yang
  • Jinge Liu
  • Kata Terecskei
  • Edit Ábrahám
  • Anikó Gombár
  • Ágota Domonkos
  • Attila Szűcs
  • Péter Körmöczi
  • Ting Wang
  • Lili Fodor
  • Linyong Mao
  • Zhangjun Fei
  • Éva Kondorosi
  • Péter Kaló
  • Attila Kereszt
  • Hongyan Zhu
چکیده

Legumes engage in root nodule symbioses with nitrogen-fixing soil bacteria known as rhizobia. In nodule cells, bacteria are enclosed in membrane-bound vesicles called symbiosomes and differentiate into bacteroids that are capable of converting atmospheric nitrogen into ammonia. Bacteroid differentiation and prolonged intracellular survival are essential for development of functional nodules. However, in the Medicago truncatula-Sinorhizobium meliloti symbiosis, incompatibility between symbiotic partners frequently occurs, leading to the formation of infected nodules defective in nitrogen fixation (Fix-). Here, we report the identification and cloning of the M. truncatula NFS2 gene that regulates this type of specificity pertaining to S. meliloti strain Rm41. We demonstrate that NFS2 encodes a nodule-specific cysteine-rich (NCR) peptide that acts to promote bacterial lysis after differentiation. The negative role of NFS2 in symbiosis is contingent on host genetic background and can be counteracted by other genes encoded by the host. This work extends the paradigm of NCR function to include the negative regulation of symbiotic persistence in host-strain interactions. Our data suggest that NCR peptides are host determinants of symbiotic specificity in M. truncatula and possibly in closely related legumes that form indeterminate nodules in which bacterial symbionts undergo terminal differentiation.

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عنوان ژورنال:
  • Proceedings of the National Academy of Sciences of the United States of America

دوره 114 26  شماره 

صفحات  -

تاریخ انتشار 2017