The genetic structure and diversity of Gentiana lutea subsp. lutea (Gentianaceae) in Sardinia: further insights for its conservation planning

Knowledge of the levels of genetic diversity and of the spatial genetic structure of plant species is important to ensure their effective management and conservation, especially in the case of endangered species. Gentiana lutea L. subsp. lutea is a long-lived plant which occurs in central and southern European mountains. It has a long-standing history of human exploitation, mainly in the liqueur and in the pharmaceutical industries and it is currently listed in the EU Habitats Directive 92/43/EEC Annex V. Mainly due to a prolonged root harvesting, its current distribution range in Sardinia consists of only a few groups of individuals limited to small areas of the Gennargentu massif (Central-Eastern area of the island). In this study, we investigated the levels of genetic diversity and the genetic structure of the species in Sardinia. We used AFLP (amplified fragment length polymorphism) markers to investigate the genetic variability of 182 samples from 13 subpopulations. A total of 433 fragments were detected, of which 75.5% were polymorphic. The levels of genetic diversity were generally high, but they tended to decrease in smaller subpopulations. Of the genetic variability 88% was found within subpopulations, while the genetic structure among them was fairly weak. In order to ensure the survival of these subpopulations, especially the smaller ones, ex situ and in situ management actions should be planned, such as the long term conservation of its seeds in germplasm repositories and their population reinforcements and monitoring.