1Laboratoire d' Evolution et Systématique, Centre National de la Recherche Scientifique, URA 2154, Université Paris XI, Bât 362, 91405 Orsay, France; 2Institut des Sciences Végétales, Centre National de la Recherche Scientifique, UPR40, Avenue de la Terrasse, 91198 Gif-sur-Yvette CEDEX, France
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Accepted 14 July 1999.
Two lines of Medicago truncatula, R-108-1 and Jemalong J5, exhibit differences in their symbiotic properties, morphological markers, and capacity for regeneration and transformation. Using cytogenetic techniques, we detected differences in chromomycin A3 staining on the two sides of the secondary constriction of the nucleolar chromosome pair of J5 and R-108-1, while DAPI (4′, 6-diamidino-2-phenylindole) staining revealed no differences between the two lines. FISH (fluorescent in situ hybridization) analysis showed a difference between J5 and R-108-1 for the same 5S rRNA genes; three loci were found in J5 but only two loci in R-108-1. However, for the 18S-5.8S-26S rDNA genes only a single locus was found in both lines. Based on these analyses, a karyotype for the two lines was established.
© 1999 The American Phytopathological Society