Summary
Certain alfalfa plants can develop non-nitrogen fixing structures on their root systems when grown in testtubes under strictly axenic conditions. We demonstrate that these structures possess all the histological features characteristic of indeterminate nodules and that their formation is inhibited by combined nitrogen. The nodule morphogenesis-related gene ENOD2 is expressed in these nodules whereas leghemoglobin transcripts cannot be detected. The capacity to Nodulate in the Absence of Rhizobium (NAR) is maintained during clonal propagation of these alfalfa plants. Our results show that Rhizobium is not absolutely required for nodule morphogenesis and suggest that plant genetic determinants are involved in the NAR phenomenon.
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Truchet, G., Barker, D.G., Camut, S. et al. Alfalfa nodulation in the absence of Rhizobium . Molec. Gen. Genet. 219, 65–68 (1989). https://doi.org/10.1007/BF00261158
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DOI: https://doi.org/10.1007/BF00261158