The complete chloroplast genome sequence of the folk medicinal and vegetable plant purslane (<i>Portulaca oleracea</i>L.)

Abstract

Portulaca oleracea is an important and widely distributed medicinal and edible plant that has great economic value in the medical and food industries. We sequenced the complete chloroplast (cp) genome of P. oleracea,whichis156,533 bp in length, including a pair of inverted repeats (IRs) of 25,501 bp separated by a large single copy (LSC) region of 87,436 bp and a small single copy (SSC) region of 18,095 bp. The genome contains 85 protein-coding genes, 37 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. There are 40 repeat units and 111 simple sequence repeats (SSRs) in the genome. We also carried out complete cp genome comparison with other Caryophyllales species. The size, gene content, and structural organisation of P. oleracea are relatively conserved, but the genes ycf1 and ycf2 have larger introns. The simple sequence repeats (SSR) in the introns of ycf3, ycf1, atpB, rrn23 and ndhH have significant polymorphism. Comparisons of IR boundaries among 8 Caryophyllales species showed contraction and expansion. The complete cp genome sequence will contribute to a better understanding of the evolutionary mode of the cp genome and to the development of new markers for Caryophyllales classification.