Characterization of the complete chloroplast genome of a medicinal plant, Portulaca oleracea.

Portulaca oleracea is an important and widely distributed medicinal and edible plant, which has great economic value in the medical and food industries in the whole world. The complete chloroplast genome of Portulaca oleracea was found to possess a total length 156,533 bp and had the circular structure. It was the typical quadripartite structure the same as many plants, including 87,437 bp large single-copy region (LSC), 18,096 bp small single-copy region (SSC) of and a pair of 25,500 bp inverted repeat (IR) regions. The total of 132 genes was successfully annotated, which contained 87 protein-coding genes, 37 transfer RNA genes, and eight ribosomal RNA genes. Nineteen genes were found in one of IR, which included eight protein-coding gene, seven tRNA genes, and four rRNA genes. The overall nucleotide composition of chloroplast genome sequence is: 31.5% (A), 32.1% (T), 18.5% (C), 17.9% (G), and the total GC content of 36.4%. The phylogenetic analysis result showed that Portulaca oleracea was close to Carnegiea gigantean in the phylogenetic relationship by the neighbor-joining (NJ) method in this study.