The complete chloroplast genome sequence of Hyssopus cuspidatus Boriss. and analysis of phylogenetic relationships

Abstract

Hyssopus cuspidatus is a member of the Lamiaceae family, members of which are often used to treat cough and asthma by the Uigurs. However, the Hyssopus genus has a limited number of known chloroplast genomes, making it difficult to compare species within the genus and to classify species within and outside the genus accurately. The introduction of the chloroplast genome method would therefore help improve the classification of the Hyssopus genus. This report presents the complete chloroplast sequences of Hyssopus cuspidatus. The chloroplast genome of H. cuspidatus is 149,678 bp long and contains 129 genes, including 85 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. We identified 46 single sequence repeats (SSRs), most of which were mononucleotide adenine–thymine. The analysis of the repeat sequences, codon usage, and comparison of chloroplast genomes showed a high degree of conservation. The plastid genomes exhibited a typical quartile structure. Four hypervariable regions were identified: accD–psal, psbZ–trnG–GCC, trnH–GUG–psbA, and atpH–atpI. Phylogenetic analysis revealed that the Hyssopus genus was closely related to the adjacent genus Dracocephalum. Our research conducted a comprehensive analysis of the characteristics of the Hyssopus genus and provided a detailed comparison of the differences between species within and outside of this genus. Through IR comparison, phylogenetic analysis, and variation region analysis, we discovered a close relationship between the genera Hyssopus and Dracocephalum and propose a new perspective on the phylogenetic classification of H. cuspidatus. These findings will support the continued identification, classification, and evolutionary analysis of this genus.