Planta

, Volume 222, Issue 5, pp 848–857

Soil nematodes mediate positive interactions between legume plants and rhizobium bacteria

Authors

  • Jun-ichiro Horiuchi
    • Department of Horticulture and Landscape ArchitectureColorado State University
    • Center for Rhizosphere BiologyColorado State University
  • Balakrishnan Prithiviraj
    • Department of Horticulture and Landscape ArchitectureColorado State University
    • Center for Rhizosphere BiologyColorado State University
  • Harsh P. Bais
    • Department of Horticulture and Landscape ArchitectureColorado State University
    • Center for Rhizosphere BiologyColorado State University
  • Bruce A. Kimball
    • Graduate Degree Program in EcologyColorado State University
    • United States Department of AgricultureWildlife Services, National Wildlife Research Center
    • Department of Horticulture and Landscape ArchitectureColorado State University
    • Graduate Degree Program in EcologyColorado State University
    • Center for Rhizosphere BiologyColorado State University
Original Article

DOI: 10.1007/s00425-005-0025-y

Cite this article as:
Horiuchi, J., Prithiviraj, B., Bais, H.P. et al. Planta (2005) 222: 848. doi:10.1007/s00425-005-0025-y

Abstract

Symbiosis between legume species and rhizobia results in the sequestration of atmospheric nitrogen into ammonium, and the early mechanisms involved in this symbiosis have become a model for plant-microbe interactions and thus highly amenable for agricultural applications. The working model for this interaction states that the symbiosis is the outcome of a chemical/molecular dialogue initiated by flavonoids produced by the roots of legumes and released into the soil as exudates, which specifically induce the synthesis of nodulation factors in rhizobia that initiate the nodulation process. Here, we argue that other organisms, such as the soil nematode Caenorhabditis elegans, also mediate the interaction between roots and rhizobia in a positive way, leading to nodulation. We report that C. elegans transfers the rhizobium species Sinorhizobium meliloti to the roots of the legume Medicago truncatula in response to plant-released volatiles that attract the nematode. These findings reveal a biologically-relevant and largely unknown interaction in the rhizosphere that is multitrophic and may control the initiation of the symbiosis.

Keywords

SymbiosisLegumeSinorhizobium melilotiCaenorhabditis elegansVolatiles

Copyright information

© Springer-Verlag 2005