Structural Features and Synteny Analysis of the Sea Buckthorn Mitochondrial Genome

Background Sea buckthorn ( Hippophae rhamnoides L. ) is a plant of significant economic, culinary, medicinal, ecological, and societal value. In order to gain a deeper understanding of the sea buckthorn mitochondrial genome, sequencing and assembly of the sea buckthorn mitochondrial genome was performed, and its substructures were explored in this study. Results The mitochondrial genome of seabuckthorn consists of two circular chromosomes, with lengths of 297,507 bp and 167,037 bp, respectively. It encompasses 36 annotated protein-coding genes, 3 rRNA genes, and 25 tRNA genes. In addition, 212 pairs of repeats were detected, including a pair that mediated homologous recombination of seabuckthorn mitochondrial chromosomes to form two conformations. The existence of these conformations was confirmed through PCR amplification and Sanger sequencing. A total of 162 SSR loci were identified in the sea buckthorn mitochondrial genome. There are 30 homologous fragments in chloroplast and mitochondrial genomes, with a total length of 44,950 bp, accounting for 9.89% of the total length of mitochondrial genomes. Conclusions In summary, this study conducted the assembly and annotation of the sea buckthorn mitochondrial genome, providing a comprehensive understanding of the genome of this plant. This knowledge is of great significance for effective utilization and genetic improvement of seabuckthorn, especially in breeding and evolutionary analysis of cytoplasmic male sterility.