Species Mitogenomes Suggest Diversity and Complexity in -Order Mitogenomes

The extreme diversity and complexity of angiosperms is well known. Despite the fact that parasitic plants are angiosperms, little is known about parasitic plant mitogenomic diversity, complexity, and evolution. In this study, we obtained and characterized the mitogenomes of three species (holoparasitic plants) from China to compare the repeats, segment duplication and multi-copy protein-coding genes (PCGs), to clarify the phylogenetic and evolution relationship within the order, and to identify the mitochondrial plastid insertions (MTPT) in mitogenomes. The results showed that the mitogenome sizes of the three species ranged from 1,708,661 to 3,978,341 bp. The species genome encodes 75-126 genes, including 37-65 PCGs, 31-58 tRNA genes and 3-5 rRNA genes. Compared with other and parasitic species, the species showed extremely high rates of multi-copy PCGs, ranging from 0.13 to 0.58 percent of the total number of PCGs. In addition, 37-133 Simple Sequence Repeat (SSRs) were found in these three mitogenomes, the majority of which were the mononucleotides Adenine/Thymine. The interspersed repeats contained forward and palindromic repeats. Furthermore, the segment-duplication sequence size ranged from 199,584 to 2,142,551 bp, accounting for 24.9%, 11.7% and 53.9% of the , and mitogenome, respectively. Furthermore, the Ka/Ks analysis suggested that the 4, , and were probably positively selected during evolution. The plastome suggested the presence of MTPT. Moreover, 6-12 tRNA, 9-15 PCGs fragments and 3 rRNA gene fragments in the mitogenomes were found in the MTPT regions. This work reports the species mitogenome for the first time, which will be invaluable for study the mitogenome evolution of family.