49. RFLP analysis of rice mitochondrial DNA

Takashige ISHII1,2 and Koichiro TSUNEWAKI1

1) Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Kyoto, 606 Japan

2) Present address: Plant Breeding Department, International Rice Research Institute, P.O. Box 933, Manila, Philippines

Previously, we have reported the chloroplast (ct) genome differentiation in the A-genome diploid species (Ishii et al. 1988). In two cultivated rice species, Oryza sativa and O. glaberrima, four chloroplast genome types (type 1, 3, 4 and 5) were found. We selected ten cultivars representing all the four chloroplast genome

Table 1. Materials used as the source of mitochondrial DNA and 
         their chloroplast (ct) genome types
________________________________________________________________
Accession no.        Taxon              Code      Ct genome type
________________________________________________________________
1.             O.   sativa Japonica       J1             1
2.                     ""                 J2             1
3.                     "   Javanica       Jv1            1
4.                     ""                 Jv2            1
5.                     "   Indica         I1             1
6.                     ""                 I2             3
7.                     ""                 I3             3
8.                     ""                 I4             4
9.             O. glaberrima              G1             5
10.                    ""                 G2             5
11.            O. perennis Asian form     As1            3
________________________________________________________________
types and an additional accession of O. perennis having type 3 chloroplast genome (Table 1). RFLP analysis of the mitochondrial (mt) DNA was carried out in


Fig. 1. a) BamHl restriction fragment pattern of mtDNAs from 11 oryza accessions.b) Southern blot hybridization of the same pattern with wheat RRN18&5 probe. The code of the materials is given in Table 1.


Fig. 2. A dendogram showing genetic relationships between mitochondrial DNAs of 11 Oryza accessions, that was constructed by a UPGM method applied for the percentage of common fragments.

order to clarify their differentiation. MtDNAs were digested with five res triction 1 endonucleases, BamHI, HindiII, PstI, PvuII and XhoI. After agarose gel electrophoresis, they were hybridized with four mtDNA probes (ATPA and COXII from pea, :and RRN26 and RRN18&5 from wheat) (Fig. 1). Based on the 20 pairs of hybridization pattern (5 enzymes X 4 probes), mtDNAs of the 11 accessions could be classified into five types. Their genetic relationship were shown by a dendrogram constructed by a UPGM method applied for the percentage of the common fragments (Fig. 2).

The differentiations of chloroplast and mitochondrial genomes are found to be well paralleled to each other in cultivated rice species. Quite different mtDNA hybridization patterns were found among the cultivars and wild accession having type 3 chloroplast genome. Using ctDNA and mtDNA as the marker, phylogenetic relationship between wild and cultivated rice species will be studied more in detail.

Reference

Ihii, T., T. Terachi and K. Tsunewaki, 1988. Restriction endonuclease analysis of chloroplast DNA from A-genome diploid species of rice. Jpn. J. Genet. 63: 523-536.