The complete chloroplast genome of Origanum vulgare L. (Lamiaceae)

Abstract

Oregano (Origanum vulgare L., Lamiaceae) is a medicinal and aromatic plant maybe best known for flavouring pizza. New applications e.g. as natural antioxidants for food are emerging due to the plants' high antibacterial and antioxidant activity. The complete chloroplast (cp) genome of Origanum vulgare (GenBank/EBML/DDBJ accession number: JX880022) consists of 151,935 bp and includes a pair of inverted repeats (IR) of 25,527 bp separated by one small and one large single copy region (SSC and LSC) of 17,745 and 83,136 bp, respectively. The genome with an overall GC content of 38% hosts 114 genes that covering 63% of the genome of which 8% were introns. The comparison of the Origanum cp genome with the cp genomes of two other core lamiales (Salvia miltiorrhiza Bunge and Sesamum indicum L.) revealed completely conserved protein-coding regions in the IR region but also in the LSC and SSC regions. Phylogenetic analysis of the lamiids based on 56 protein-coding genes give a hint at the basic structure of the Lamiales. However, further genomes will be necessary to clarify this taxonomically complicated order. The variability of the cp within the genus Origanum, studied exemplarily on 16 different chloroplast DNA regions, demonstrated that in 14 regions analyzed, the variability was extremely low (max. 0.7%), while only two regions showed a moderate variability of up to 2.3%. The cp genome of Origanum vulgare contains 27 perfect mononucleotide repeats (number of repeats>9) consisting exclusively of the nucleotides A or T. 34 perfect repeats (repeat lengths>1 and number of repeats>3) were found, of which 32 were di-, and 2 were trinucleotide repeats.

Keywords: ATP; Adenosine triphosphate; Base pair(s); CTAB; Cetrimonium bromide; Chloroplast; Chloroplast genome; DNA; Deoxyribonucleic acid; I; IGS; IR; Insertion/deletion; Intergenic spacer; Intron; Inverted repeat; Kilobase(s); LSC; Lamiales; Large single-copy region; Microsatellites; NADPH; Nicotinamide adenine dinucleotide phosphate; Oregano; Origanum; RNA; Ribonucleic acid; Ribosomal RNA; SSC; SSR; Simple sequence repeat(s); Small single-copy region; Subspecies; Transfer RNA; bp; cp; indel; kb; rRNA; ssp; tRNA.