Genome-wide characterization of genetic diversity and population structure of Valeriana officinalis L.

Abstract

Background: Valeriana officinalis L. is one of the most important medicinal plant with a mild sedative, nervine, antispasmodic and relaxant effect. Despite a substantial number of studies on this species, population genomics has not yet been analyzed. The main aim of this study was: characterization of genetic variation of natural populations of V. officinalis in Poland and comparison of variation of wild populations and the cultivated form using Next Generation Sequencing based DArTseq technique. We also would like to establish foundations for genetic monitoring of the species in the future and to develop genetic fingerprint profile for samples deposited in gene bank and in natural sites in order to assess the degree of their genetic integrity and population structure preservation in the future.Results: The major and also the most astounding result of our work is the low level of observed heterozygosity of individual plants from natural populations despite the fact that the species is widespread in the studied area. Inbreeding, in naturally outcrossing species such as valerian, decreases the reproductive success. The analysis of the population structure indicated the potential presence of metapopulation in a broad area of Poland and the formation of a distinct gene pool in Bieszczady Mountains. The results also indicate the presence of individuals of the cultivated form in natural populations in the region where the species is cultivated for the needs of the pharmaceutical industry and this could lead to structural and genetic imbalance in wild populations.Conclusions: The DArTseq technology can be applied effectively in genetic studies of V. officinalis. The genetic variability of wild populations is in fact significantly lower than assumed. Individuals from the cultivated population are found in the natural environment and their impact on wild populations should be monitored.