Widespread Occurrence of the Homologues of the Early Nodulin (ENOD) Genes inOryzaSpecies and Related Grasses

Eighty accessions representing 23 species from the genusOryzawere examined for the presence of homologues of early nodulin (ENOD) genes. Southern analyses indicated a widespread distribution of homologues ofENODgenes across all the genomes of rice as well as other monocots. The degree of cross-hybridization of the legumeENODgenes with sequences in the genomes of various species, as revealed by hybridization differentials measured in terms of signal intensities, however, suggests that the homologues ofENODgenes are conserved to varied extents in differentOryzaspecies. The presence of homologues ofENODgenes in a wide variety of plant species denotes that the biological functions of early nodulins may be diverse, and not restricted to nodule organogenesis alone. The fact thatENODgene homologues exist widely both in dicots and monocots provides evidence that these homologues have arisen from a common ancestral plant.