Population genetics of the endemic and endangered Vriesea minarum (Bromeliaceae) in the Iron Quadrangle, Espinhaço Range, Brazil

Abstract

• Premise of the study: Knowledge about genetic variability in plant populations is one of the main branches of conservation genetics, linking genetic data to conservation strategies. Vriesea minarum is a bromeliad endemic to the Iron Quadrangle region (southeastern Brazil), occurring on mountaintop rock outcrops. It is listed as endangered due to habitat loss, particularly from iron ore mining. Thus, determining the structure and genetic diversity of V. minarum populations could help develop strategies to conserve the species.• Methods: We studied the genetic structure of 12 populations of V. minarum using 10 microsatellite loci transferred from other species of Bromeliaceae. Statistical analyses to compare and describe the genetic diversity of each population were performed, and genetic structure within and among populations, isolation by distance, and Bayesian structure were also analyzed.• Key results: Our results show high inbreeding (G = 0.376) and low population structure (F = 0.088), possibly related to high gene flow due to great pollinator efficiency and/or efficient seed dispersal, thus leading to high connectivity among populations of these fragmented rock outcrops. Two clusters were observed, corresponding to the basins of rivers São Francisco and Doce.• Conclusions: Gene flow among populations is high but, given the rate of habitat loss to mining, most populations are vulnerable and will become increasingly isolated if no action is taken to preserve them. Thus, conservation of this species depends on in situ and ex situ actions, such as controlling overexploitation and creating a germoplasm bank.

Genetic diversity of Bromeliaceae species from the Atlantic Forest

“…Unlike the pattern found for Alcantarea imperialis (Carrière) JR Grant and Aechmea geniculata (Wawra) JR Grant (Barbará et al, 2007), in Vriesea gigantea , and also Vriesea minarum (Lavor et al, 2014), the observed heterozygosity was lower than expected because of a deficit of heterozygotes. These data further suggest that an excess of homozygotes could be due to selfing or biparental inbreeding, since V. minarum exhibits a mixed reproductive strategy (outcrossing + self-compatibility), or due to a feature of the subfamily Tillandsioideae.…”

“…Plants in the Bromeliaceae family provide excellent models for the study of genetic diversity (Zanella et al, 2012;Hmeljevski et al, 2013), population genetics (Lavor et al, 2014), as well as the divergence between populations and species (Sarthou et al, 2001;Barbará et al, 2007;Palma-Silva et al, 2009). Bromeliads are an important and characteristic element of Neotropical forests, especially in the Brazilian Atlantic Forest (BAF), where they are among those families with the greatest richness and diversity (Martinelli et al, 2008).…”

“…Nevertheless, relatively few genetic studies have examined Neotropical plant species and investigated genetic aspects of BAF bromeliads by comparing temperate forests (Cavallari et al, 2006;Barbará et al, 2007;Palma-Silva et al, 2009;Versieux et al, 2012;Zanella et al, 2012;Lavor et al, 2014;Goetze et al, 2015). According to Zanella et al (2012), only 20 species of the following nine genera have been previously evaluated, and most of the studied species are endemic to the Atlantic rainforest in southeastern Brazil: Aechmea, Alcantarea, Bromelia, Dyckia, Encholirium, Pitcairnia, Puya, Tillandsia, and Vriesea. However, this biome has been severely destroyed and reduced to only 13% approximately of its original area, which is the main threat to BAF flora and fauna (Ribeiro, 2009).…”

“…Therefore, research on population genetic diversity is essential to provide information on the risk of species extinction and to design effective conservation strategies (Frankham et al, 2002). In this context, molecular markers are widely used for studying genetic variability (Cavallari et al, 2006;Barbará et al, 2007Barbará et al, , 2009Lavor et al, 2014;Goetze et al, 2015), and several markers have been developed for Bromeliaceae: Pitcairnia (Sarthou et al, 2003;Paggi et al, 2008), Alcantarea , Dyckia (Zanella et al, 2012), Encholirium (Hmeljevski et al, 2013), Orthophytum (Aoki-Gonçalves et al, 2014), and recently, Vriesea (Neri et al, 2015).…”

Differentiation and genetic diversity of Phaseolus lunatus wild populations from Chiapas, Mexico, and their genetic relationships with MI and MII groups

“…These markers have proved a useful tool for determining the genetic structure in many plant species (Mattioni et al 2013, Lavor et al 2014, Noormohammadi et al 2014, Shivaprakash et al 2014. In wild Phaseolus lunatus, SSRs have been used to determine the genetic structure in populations of Costa Rica and Mexico, showing high genetic differentiation between wild populations of P. lunatus and clustering patterns based on geographical isolation and low levels of gene flow (Ouédraogo et al 2005, Martínez-Castillo et al 2006.…”