Origin and evolution of the plant genome; with a focus on mitochondrial and plastid genomes

摘要

It is generally known that one of the most serious events when eukaryotic cells arose was endosymbiosis. First, an ancestral alpha-proteobacterium had been engulfed into the host cell and evolved into the mitochondrion. Second, an ancestral cyanobacteria had been engulfed and evolved into the plastid. The cell nucleus of plant, therefore, is thought to be the fusion of the three kinds of cell nucleus of the organisms, To clarify the construction of plant cell, we began to analyze the genome structure and gene content of a very primitive plant, Cyanidioschyzon merolae (unicellular rhodophytes). In the course of the determination of complete nucleotide sequence, we first completed the nucleotide sequences of organelles, namely, the mitochondrial genome and the plastid genome. The gene contents of the two organellar genomes clearly show that the C. merolae is thought to be an intermediate along the evolutionary way. Now, whole genome sequencing project of the cell nucleus of C. merolae is proceeding.