Association between chemical and genetic variation of wild and cultivated populations of Scrophularia ningpoensis Hemsl.

Scrophularia ningpoensis Hemsl. is an important Chinese medicinal herb with a domestication history of more than one thousand years. Although a number of studies have focused on either chemical or genetic variation, none have dealt with their association to discuss the formation of chemical diversity. We applied HPLC fingerprinting with identification of four predominant bioactive compounds using LC-ESI-MS to assess chemical variation among 6 cultivated and 5 wild populations of S. ningpoensis. Significant chemical differences were revealed between wild and cultivated populations in terms of chromatographic profiles, principal component analysis (PCA) plots, and bioactive compounds contents. Compared to cultivated populations, the chemical profiles varied considerably among wild populations, of which some were remarkably similar to cultivated populations. Inter simple sequence repeats (ISSR) fingerprinting indicated a genetic differentiation pattern parallel to chemical variation. Evidence strongly supported the association between chemical and genetic variation of S. ningpoensis. Based on both sets of data, suggestions are proposed for the conservation of genetic diversity, crop improvement, and good agricultural practice. The present results will also facilitate our theoretical understanding of the selective and adaptive evolutionary processes of medicinal plant species impacted by domestication and a changing environment.