Widespread occurrence of the homologues of the early nodulin (ENOD) genes in Oryza species and related grasses

Eighty accessions representing 23 species from the genus Oryza were examine d for the presence of homologues of early nodulin (ENOD) genes. Southern an alyses indicated a widespread distribution of homologues of ENOD genes acro ss all the genomes of rice as well as other monocots, The degree of cross-h ybridization of the legume ENOD genes with sequences in the genomes of vari ous species, as revealed by hybridization differentials measured in terms o f signal intensities, however, suggests that the homologues of ENOD genes a re conserved to varied extents in different Oryza species, The presence of homologues of ENOD genes in a wide variety of plant species denotes that th e biological functions of early nodulins may be diverse, and not restricted to nodule organogenesis alone. The fact that ENOD gene homologues exist wi dely both in dicots and monocots provides evidence that these homologues ha ve arisen from a common ancestral plant. (C) 1999 Academic Press.