| Characterization of mitochondrial DNAs in two alloplasmic
and a normal line of common wheat by four restriction enzymes
Yasunari OGIHARA Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Kyoto It is well known that some genetic factors are located in cytoplasm and transmitted uniparentally in most plants, involving wheat. Various cytoplasms in two genera Triticum and Aegilops were introduced into common wheat by repeated back crosses, and were classified into twelve cytoplasm types depending upon the nucleus-cytoplasm interaction (TSUNEWAKI et al. 1980). It is also well established that an appreciable amount of DNA is contained in various cytoplasmic organelles, such as the chloroplast and mitochondrium. Unique behaviors of the twelve cytoplasms against the common wheat nucleus might be due to the presence of unique DNAs in their organelles. Now, we started studies on the diversity of organella DNAs using their cleavage by several restriction endonucleases. I herewith report some differences between the cleavage patterns of mitochondrial DNAs isolated from two alloplasmic and a normal line of common wheat. Mitochondrial DNAs were isolated from etiolated seedlings (5 days old) of a normal and two alloplasmic lines of a common wheat, Chinese Spring (abbrev. CS). The alloplasmic lines used were (kotschyi)- and (timopheevi)-CS. Plasma types of normal CS, (kotschyi)-CS and (timopheevi)-CS were S, G and Sv, respectively. The DNAs isolated were digested by four restriction endonucleases, Eco RI, Bam HI, Hind III and Bst EII. The digests were separated by 1% agarose slab gel electophoresis. The mitochondrial DNA of the normal line was digested by all four enzymes to form about 50 separable bands, whose molecular weights varied from ca. 15 x 106 to 0.1 x 106 dalton. The number of DNA bands observed was similar to that previously reported in wheat (Vedel et al, 1978) and maize (Pring and Levings 1978). The electrophoretic patterns of the mitochondrial DNAs isolated from three different cytoplasms showed detectable differences from each other at least in the digest of one restriction enzyme. This result suggests that mitochondrial genomes have been differentiated clearly among the three different cytoplasms. References PRING, D.R. and C.S. LEVINGS III. 1978. Heterogeneity of maize cytoplasmic genomes among malesterile cytoplasms. Genetics 89: 121-136. TSUNEWAKI, K., Y. MUKAI and T. Ryu ENDO. 1980. Genetic diversity of the cytoplasm. In "Genetic diversity of the cytoplasm in Triticium and Aegilops." Ed. K. Tsunewaki. Japan Soc. Promotion of Science. VEDEL. F., F. QUETIER, F. DOSBA and G. DOUSSINAULT. 1978. Study of wheat phylogeny by Eco RI analysis of chloroplastic and mitochondrial DNAs. Plant Sci. Letters 13: 97-102. |