Molecular basis of plasmon diversity in Triticum and Aegilops

Genetic information of plants is preserved in the tripartite organellar, i.e., nucleus, plastome, and chondriome. Each organelle contains its DNA. To characterize the structures of plastome and chondriome in wheat species, the entire sequence of chloroplast DNA and mitochondrial DNA of Chinese Spring wheat was determined. Chloroplast DNA of Chinese Spring wheat conferred the 134,545 bp circular molecule with 20,703 bp inverted repeats and the same size and gene content as those of the rice and maize, indicating the conservation of the plastome among angiosperms. This conservation of the plastome among plant species allows us to investigate the variation of the plastome and their phylogenetic relationships among wheat species in the maternal lineage. On the other hand, the mitochondrial genome of angiosperms revealed complex structures. Consequently, cosmid walking of the mitochondrial DNA in the Chinese Spring wheat was carried out to construct the master copy that contains all reported genes in it. Complex features of the wheat mitochondrial genome through the recombination were able to be clarified. Paternal transmissions of mitochondrial DNAs were disclosed. To conduct the plasmon investigation of wheat species, alloplasmic lines of common wheat, which were systematically produced by Prof. Tsunewaki were indispensable. We sincerely acknowledge his great contribution to the plasmon study of wheat species.