Abstract
The birth of land plants is an important step in plant evolution. Here, we report the complete nucleotide sequence (105,340 bp) of the circular mitochondrial genome of the moss Physcomitrella patens. This genome, being the smallest among the sequenced mitochondrial genomes of land plants reported to date, contains genes encoding three rRNAs, 24 tRNAs and 42 conserved mitochondrial proteins. The overall structure of mitochondrial genome is essentially similar in P. patens, Chara vulgaris, Chaetosphaeridium globosum and Marchantia polymorpha, but poor synteny with these was detected in green algae and angiosperms. Phylogenetic analysis using 18 conserved proteins suggested that the moss-liverwort clade is sister to angiosperms. Available evidence suggests that multipartite structure of mitochondrial genome as found in flowering plants does not occur in Physcomitrella. All these data suggest that the mitochondrial genome of Physcomitrella retains prototype features among land plant mitochondrial genomes.
