Differentiation and inter-genomic relationships among C, E and D genomes in the Oryza officinalis complex (Poaceae) as revealed by multicolor genomic in situ hybridization uri icon

abstract

  • The multicolor genomic in situ hybridization (McGISH) method was used to study differentiation and relationships among the C, D and E genomes in the officinalis complex of the genus Oryza. The chromosomes of Oryza alta (CCDD genomes) were hybridized with labelled probes of the C genome (from diploid Oryza eichingeri and Oryza officinalis) and the E genome (from Oryza australiensis) simultaneously. By adjusting the post-hybridization washing stringency in a gradual series, differentiation between the genomes was detected according to the homology between the target genomes and the probes. The McGISH results indicate that the C, D and E genomes, share a substantial amount of similar sequences, and differentiation between the D and C genomes of O. alta is less than that between the E genome and each of the C and D genomes. The differentiation within the C genomes of diploid species (O. officinalis and O. eichingeri) and the C genome of O. alta was clearly discerned by McGISH, suggesting strongly that neither O. officinalis nor O. eichingeri was the direct C-genome donor of O. alta. The evidence of the GISH results also indicates that the E genome was considerably differentiated from the C and D genomes. Therefore, the E genome should not be the direct donor of O. alta; on the contrary, the E genome is closer to the C than to the D genome. McGISH is an efficient method in revealing the relationships among the genomes in question, particularly under the gradual stringent-washing condition.

publication date

  • 2001
  • 2001