Characterization and Phylogenetic Analysis of Chloroplast Genome Structure of CITES Appendix Species Tephrocactus geometricus

The high-throughput sequencing of illumina platform was used to sequence and assembled the whole chloroplast genome of CITES Appendix Species Tephrocactus geometricus, and its structural characteristics and phylogenetic relationship were analysed. The results showed that the chloroplast genome was a typical tetrad structure. The genome was found to be 116 183 bp in length, with 72 protein coding genes, 6 ribosomal RNA genes, and 30 transfer RNA genes. The chloroplast genome encoded a total of 16 119 codons, with Leu being the most common. A total of 259 microsatellite sites were detected in the chloroplast genome, with the highest single nucleotide repeat sequence being 186. A phylogenetic tree was constructed using the ML, which showed that T. geometricus was closely related to the Carnegiea gigantea. This study provided a theoretical basis for the development of molecular markers, research on phylogenetic relationships, chloroplast transformation techniques and analysis of endangered mechanisms. At the same time, it also enriched the genetic information of the chloroplast genome of Cactaceae plants.