Research Article: The plastid genome and its implications in barcoding specific-chemotypes of the medicinal herb Pogostemon cablin in China

Date Published: April 15, 2019

Publisher: Public Library of Science

Author(s): Caiyun Zhang, Tongjian Liu, Xun Yuan, Huirun Huang, Gang Yao, Xiaolu Mo, Xue Xue, Haifei Yan, Tzen-Yuh Chiang.


Pogostemon cablin (Blanco) Benth. (Patchouli) is not only an important essential oil plant, but also a valuable medicinal plant in China. P. cablin in China can be divided into three cultivars (Shipai, Gaoyao, and Hainan) and two chemotypes (pogostone-type and patchoulol-type). The pogostone-type and patchoulol-type are, respectively, used for medicinals and perfumes. In this study, we sequenced and characterized the plastid genomes for all three Chinese cultivars and aimed to develop a chemotype-specific barcode for future quality control. The plastid genomes of P. cablin cultivars ranged from 152,461 to 152,462 bp in length and comprise 114 genes including 80 protein coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analyses suggested that P. cablin cultivars clustered with the other two Pogostemon species with strong support. Although extremely conserved in P. cablin plastid genomes, 58 cpSSRs were filtered out among the three cultivars. One single variable locus, cpSSR, was discovered. The cpSSR genotypes successfully matched the chemotypes of Chinese patchouli, which was further supported by PCR-based Sanger sequences in more Chinese patchouli samples. The barcode developed in this study is thought to be a simple and reliable quality control method for Chinese P. cablin on the market.

Partial Text

Pogostemon cablin (Blanco) Benth. (Lamiaceae), commonly called Patchouli, is a commercially important plant for its essential oil (patchouli oil). The species has been cultivated widely in China, India, Indonesia, Malaysia, the Philippines, and Singapore [1, 2]. However, information on the natural distribution of P. cablin is lacking, and its wild populations may be extinct [3–5]. Patchouli oil is an important ingredient in perfume and cosmetics industries because it possesses a fixative property that makes other fragrances longer lasting [4, 6]. P. cablin is reported as one of the top 20 essential oil yielding plants and is considered to have tremendous economic potential [4].




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