Unique repeat and plasmid sequences in the mitochondrial genome of Gracilaria chilensis (Gracilariales, Rhodophyta)

We described the complete mitochondrial genome of Gracilaria chilensis (Gracilariales), an economically important agarophyte alga. The genome was a 26,898 bp circular DNA with 27.6% guanine-cytosine (GC) content, and it encoded 25 protein-coding genes, two ribosomal RNAs (rRNAs), 26 transfer RNAs (tRNAs), and an intron (499 bp) in trnI. The gene composition was similar to that of the published mitogenome of G. salicornia; however, one inverted and several direct repeat sequences occurred between secY and orf148 genes, resulting in duplicated trnR and trnS tRNA sequences. The mitochondrial genome also contained three integrated partial plasmid sequences, which were reported for G. robusta (Gro4059).