A genetic delineation of Patchouli (Pogostemon cablin) revealed by specific-locus amplified fragment sequencing

Patchouli plant (Pogostemon cablin (Blanco) Benth.) is of important economic value, and it has been grown for medicinal use for more than 1000 years in China and Southeast Asia. There are limited data to underpin the genetic and genomic resource management for Patchouli. Herein, we used specific-locus amplified fragment sequencing to generate a genetic delineation of P. cablin collected from Vietnam, South China, and Indonesia (Sumatra). In total, 15457835 reads, 61334 specific-locus amplified fragments, and 511 reliable single nucleotide polymorphisms were obtained. On the basis of model-based grouping and neighbor-joining trees, we divided the studied accessions into six distinct groups: one Vietnamese group, two Chinese groups, and three Indonesian groups. We also measured the contents of patchouli alcohol and pogostone; all accessions belonged to patchoulol-type except for three accessions from the species' northernmost distribution in China, which have a high content of pogostone. The results from both genetic structure and chemotypes were highly consistent with the possible migration history of Patchouli. Accordingly, ex situ conservation should be immediately established for Patchouli, particularly for the pogostone-type and the germplasm in Vietnam.