Were sea level changes during the Pleistocene in the South Atlantic Coastal Plain a driver of speciation in Petunia (Solanaceae)?

Abstract

BackgroundQuaternary climatic changes led to variations in sea level and these variations played a significant role in the generation of marine terrace deposits in the South Atlantic Coastal Plain. The main consequence of the increase in sea level was local extinction or population displacement, such that coastal species would be found around the new coastline. Our main goal was to investigate the effects of sea level changes on the geographical structure and variability of genetic lineages from a Petunia species endemic to the South Atlantic Coastal Plain. We employed a phylogeographic approach based on plastid sequences obtained from individuals collected from the complete geographic distribution of Petunia integrifolia ssp. depauperata and its sister group. We used population genetics tests to evaluate the degree of genetic variation and structure among and within populations, and we used haplotype network analysis and Bayesian phylogenetic methods to estimate divergence times and population growth.ResultsWe observed three major genetic lineages whose geographical distribution may be related to different transgression/regression events that occurred in this region during the Pleistocene. The divergence time between the monophyletic group P. integrifolia ssp. depauperata and its sister group (P. integrifolia ssp. integrifolia) was compatible with geological estimates of the availability of the coastal plain. Similarly, the origin of each genetic lineage is congruent with geological estimates of habitat availability.ConclusionsDiversification of P. integrifolia ssp. depauperata possibly occurred as a consequence of the marine transgression/regression cycles during the Pleistocene. In periods of high sea level, plants were most likely restricted to a refuge area corresponding to fossil dunes and granitic hills, from which they colonized the coast once the sea level came down. The modern pattern of lineage geographical distribution and population variation was established by a range expansion with serial founder effects conditioned on soil availability.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0363-8) contains supplementary material, which is available to authorized users.

The xeric side of the Brazilian Atlantic Forest: The forces shaping phylogeographic structure of cacti

“…Further, Pleistocene climatic changes have also been invoked to explain diversification within BAF (e.g., Cabanne et al., ; Cardoso, Cristiano, Tavares, Schubart, & Heinze, ), by persistence of rainforest species in stable areas (refugia) in the northern bioclimatic region and expansion of open vegetation formation in the south (Carnaval et al., ). These global climatic changes also had impacts on sea level, which in turn might have influenced the geographic distribution of coastal vegetation (Ramos‐Fregonezi et al., ), for instance by the exposition of Brazilian continental shelf during glacial periods (Leite et al., ).…”

Contribution of WUSCHEL-related homeobox (WOX) genes to identify the phylogenetic relationships among Petunia species

“…integrifolia under the latter taxa, justifying this choice with the association of several characteristics to the different environments where these plants grow. Previous evolutionary approaches (Longo et al , 2014; Reck-Kortmann et al , 2014; Ramos-Fregonezi et al , 2015) have supported the suggestions of Stehmann and Bohs (2007) and Stehmann et al (2009), but the genetic variation found in WOX genes reinforces the proposition of Ando et al (2005a,b), this indicating the need for more studies including these different morphologies.…”

Landscape and climatic features drive genetic differentiation processes in a South American coastal plant

“…Despite the differences in the intraspecific divergence history between C. heterophylla (Mäder et al, 2013) and the codistributed P. integrifolia subsp. depauperata (Ramos-Fregonezi et al, 2015), both taxa shared the same pattern of high genetic admixture based on microsatellite data in populations located at the east of Patos Lagoon (Silva-Arias et al, 2017). This congruent pattern between species indicates that the current and historical dynamics in the topographical and environmental conditions in SACP are responsible for the admixture patterns and the genetic structure in this region.…”

“…The most substantial transgression and regression cycles let the formation of four main sand barriers to be positioned parallel to the coastline (barrier-lagoon systems I to IV; Tomazelli et al, 2000;Tomazelli and Dillenburg, 2007). The harsh environment, such as strong spring-summer sea breezes from the northeast and high insolation, strongly influences this region such as strong spring-summer sea breezes from the northeast and high insolation (Dillenburg et al, 2009), which was responsible for the current topography and, consequently, influenced the distribution and variability of genetic lineages in contemporary plants (e.g., Mäder et al, 2013;Ramos-Fregonezi et al, 2015;Silva-Arias et al, 2017).…”