A Multi-Faceted Approach to Analyse the Effects of Environmental Variables on Geographic Range and Genetic Structure of a Perennial Psammophilous Geophyte: The Case of the Sea Daffodil Pancratium maritimum L. in the Mediterranean Basin

Abstract

The Mediterranean coastline is a dynamic and complex system which owes its complexity to its past and present vicissitudes, e.g. complex tectonic history, climatic fluctuations, and prolonged coexistence with human activities. A plant species that is widespread in this habitat is the sea daffodil, Pancratium maritimum (Amaryllidaceae), which is a perennial clonal geophyte of the coastal sands of the Mediterranean and neighbouring areas, well adapted to the stressful conditions of sand dune environments. In this study, an integrated approach was used, combining genetic and environmental data with a niche modelling approach, aimed to investigate: (1) the effect of climate change on the geographic range of this species at different times {past (last inter-glacial, LIG; and last glacial maximum, LGM), present (CURR), near-future (FUT)} and (2) the possible influence of environmental variables on the genetic structure of this species in the current period. The genetic results show that 48 sea daffodil populations (867 specimens) display a good genetic diversity in which the marginal populations (i.e. Atlantic Sea populations) present lower values. Recent genetic signature of bottleneck was detected in few populations (8%). The molecular variation was higher within the populations (77%) and two genetic pools were well represented. Comparing the different climatic simulations in time, the global range of this plant increased, and a further extension is foreseen in the near future thanks to projections on the climate of areas currently—more temperate, where our model suggested a forecast for a climate more similar to the Mediterranean coast. A significant positive correlation was observed between the genetic distance and Precipitation of Coldest Quarter variable in current periods. Our analyses support the hypothesis that geomorphology of the Mediterranean coasts, sea currents, and climate have played significant roles in shaping the current genetic structure of the sea daffodil especially during LGM because of strong variation in coastline caused by glaciations.

Genetic diversity and molecular characterization of naturalPancratium maritimum L. populations by DNA markers

“…They also reported 6 private alleles for populations from Israel and Croatia and 5 private alleles for Rhodes and two different populations from Italy. The numbers of individual analyzed in these populations were different from each other (De Castro et al, 2016). …”

“…We recommend high priority for these two populations in genetic resource conservation and management studies. De Castro et al (2016) reported 42 private alleles in 17 studied populations, with 1 private allele for the Turkish (Karasu-Sakarya) population. They also reported 6 private alleles for populations from Israel and Croatia and 5 private alleles for Rhodes and two different populations from Italy.…”

“…structure (Zahreddine et al, 2004;De Castro et al, 2016). The haploid chromosome number of the species is n = 11 (De Castro et al, 2012).…”

“…P. maritimum has ornamental, medicinal, pharmacological, and ecological properties, and as a consequence certain urgent conservation and management strategies are needed in order to prevent the decrease of populations of these plants (Ioset et al, 2001). The excess use of flowers for ornamental purposes, urbanization, usage of sandy beaches for tourism, sunbathing, and sand dune erosion seriously threaten the species and cause a very significant decrease of its populations Schlacher et al, 2008;Demir et al, 2010;Ciccarelli, 2015;De Castro et al, 2016).…”

“…Several studies about the chemical composition (Georgiev et al, 2011;El-Hadidy et al, 2012;Sanaa et al, 2013Sanaa et al, , 2014, pharmaceutical usage (Hetta and Shafei, 2013;Ibrahim et al, 2013), germination and seedling production (Balestri and Cinelli, 2004), in vitro micropropagation (Bogdanova et al, 2009;, and genetic diversity with morphological and molecular markers of P. maritimum have been conducted (Zahreddine et al, 2004;Grassi et al, 2005;Sanaa and Fadhel, 2010;De Castro et al, 2012;El-Hadidy et al, 2012;Di Maio and De Castro, 2013;Sanaa et al, 2014;Giovino et al, 2015;Perrone et al, 2015;Sanaa et al, 2015;De Castro et al, 2016). Based on the reviewed literature, only one previous study about genetic characterization with RAPD and SRAP primers has been carried out with regard to the two populations of sea daffodils from Turkey (Hocagil et al, 2010).…”