Comprehensive Analysis of Chloroplast Genome of IHibiscus sinosyriacus/I: Evolutionary Studies in Related Species and Genera

The Hibiscus genus of the Malvaceae family is widely distributed and has diverse applications. Hibiscus sinosyriacus is a valuable ornamental tree, but it has not been extensively researched. This study aimed to complete the chloroplast genome of H. sinosyriacus and elucidate its evolutionary relationship with closely related species and genera. The complete chloroplast genome of H. sinosyriacus was found to be 160,892 bp in length, with annotations identifying 130 genes, including 85 coding genes, 37 tRNAs, and 8 rRNAs. Interspecific variations in the Hibiscus spp. were explored, and H. sinosyriacus has species-specific single-nucleotide polymorphisms in four genes. Genome structure analysis and visualization revealed that in the Abelmoschus genus, parts of the large single-copy region, including rps19, rpl22, and rps3, have been incorporated into the inverted repeat region, leading to a duplication and an increase in the number of genes. Furthermore, within the Malvales order, the infA gene remains in some genera. Phylogenetic analysis using the whole genome and coding sequences established the phylogenetic position of H. sinosyriacus. This research has further advanced the understanding of the phylogenetic relationships of Hibiscus spp. and related genera, and the results of the structural and variation studies will be helpful for future research.