Identification of Oryza Species with the CD Genome Based on RFLP Analysis of Nuclear Ribosomal ITS Sequences

摘要

The genus Oryza consists of approximately 24 species with 10 recognized genome types (A, B, C, BC, CD, E, F, G, HJ, HK). The species with the CD genome are endemic to the Central and South America and comprise three species, i.e. O. latifolia Desv., O. alta Swallen and O. grandiglumis (Doell) Prod. Although the three species can be easily distinguished from the species with the other genomes in Oryza by their morphological characteristics, it is very difficult to distinguish them from one another. Recent studies suggested that O. alta and O. grandiglumis should be the same species (O. grandiglumis), whereas O. latifolia retains its taxonomic position unchangeably. In this paper, a total of 77 clones of the nuclear ribosomal internal transcribed spacer (ITS) from 11 samples representing different geographical races were sequenced. Using DNA Strider 1.2 software, the restriction enzyme digestion sites of these clone sequences were analyzed. Based on restriction fragment length polymorphism (RFLP) of ITS sequences, a method to identify the species with CD genome in Oryza was proposed. The method is rapid and convenient and all experimental procedure includes only three steps: (1) to amplify the ITS fragment with the routine primers; (2) to digest PCR products with restriction enzymes Fok Ⅰ and Dra Ⅲ or both; (3) to run the digested product on 1 % agarose gel and identify the sample based on the restriction profiles.