Complete Genome and Comprehensive Analysis of Knorringia sibirica Chloroplast

Knorringia sibirica is a typical species of Polygonaceae with high medicinal and ecological value. However, there are few available phylogenetic and genetic studies about the chloroplast genome of K. sibirica. In the current study, a comprehensive examination of the chloroplast genome of K. sibirica was performed. The K. sibirica chloroplast genome is 161,384 bp, circular with a typical quadripartite structure, and comprised of guanine + cytosine content of 37.63%. The genome consists of 131 genes, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Seventy simple sequence repeats were identified in the genome. When compared with three closely related species, the result revealed that the chloroplast genome of K. sibirica was conserved in genome composition and structure. The specific sites in the genome suitable for DNA barcodes were identified by calculation of the nucleotide diversity. Finally, a phylogenetic tree of 49 species in Polygonaceae was constructed using the whole chloroplast genome. The phylogenetic analysis suggested that Knorringia is an independent genus in the Polygonea tribe. This research could provide support for the utilization of genetic sources and the evolutionary study of K. sibirica.