Population genetic structure of the rock outcrop species Encholirium spectabile (Bromeliaceae): The role of pollination vs. seed dispersal and evolutionary implications.

PREMISE OF THE STUDY: Inselbergs are terrestrial, island-like rock outcrop environments that present a highly adapted flora. The epilithic bromeliad Encholirium spectabile is a dominant species on inselbergs in the Caatinga of northeastern Brazil. We conducted a population genetic analysis to test whether the substantial phenotypic diversity of E. spectabile could be explained by limited gene flow among populations and to assess the relative impact of pollen vs. seed dispersal on the genetic structure of the species. METHODS: Nuclear and chloroplast microsatellite markers were used to genotype E. spectabile individuals from 20 rock outcrop locations, representing four geographic regions: northern Espinhaço Range, Borborema Plateau, southwestern Caatinga and southeastern Caatinga. F-statistics, structure, and other tools were applied to evaluate the genetic makeup of populations. KEY RESULTS: Considerable levels of genetic diversity were revealed. Genetic structuring among populations was stronger on the plastid as compared with the nuclear level, indicating higher gene flow via bat pollination as compared with seed dispersal by wind. structure and AMOVA analyses of the nuclear data suggested a high genetic differentiation between two groups, one containing all populations from the southeastern Caatinga and the other one comprising all remaining samples. CONCLUSIONS: The strong genetic differentiation between southeastern Caatinga and the remaining regions may indicate the occurrence of a cryptic species in E. spectabile. The unique genetic composition of each inselberg population suggests in situ conservation as the most appropriate protection measure for this plant lineage.

A set of plastid microsatellite loci for the genus Dyckia (Bromeliaceae) derived from 454 pyrosequencing.

PREMISE OF THE STUDY: Phylogeographical analyses of Dyckia (Bromeliaceae) suffer from low levels of sequence variation. Plastid microsatellite markers were developed to achieve a better-resolved genus-wide plastid genealogy of Dyckia. • METHODS AND RESULTS: Approximately 84% of the D. marnier-lapostollei plastome was sequenced using 454 technology. Flanking primer pairs were designed for 34 out of 36 chloroplast simple sequence repeats (cpSSRs) detected, and 12 loci were further characterized by genotyping Dyckia samples at the level of populations and species. Three, five, and six cpSSRs were polymorphic among four individuals of D. limae, 12 individuals of D. dissitiflora, and 12 of D. pernambucana, respectively, with two to three alleles per locus and species. All loci were polymorphic among 19 different Dyckia species, with three to 10 alleles per locus. Ten primer pairs cross-amplified with bromeliad genera from five subfamilies. • CONCLUSIONS: The set of 12 cpSSR markers provides a toolbox to analyze phylogeographical patterns of Dyckia species.

Development of microsatellite markers in Fosterella rusbyi (Bromeliaceae) using 454 pyrosequencing.

PREMISE OF THE STUDY: Polymorphic microsatellite markers were developed for Fosterella rusbyi (Bromeliaceae) to evaluate the population genetic structure and genetic diversity of natural populations of F. rusbyi and other Fosterella species in Bolivia. METHODS AND RESULTS: 454 pyrosequencing technology was used to generate 73027 sequence reads from F. rusbyi DNA, which together contained 2796 perfect simple sequence repeats (SSRs). Primer pairs were designed for 30 loci, of which 15 were used to genotype 30 F. rusbyi plants from two geographical areas in Bolivia. All markers were polymorphic, with two to nine alleles in the overall sample. Cross-species amplification was tested in 10 additional Fosterella species. Seven loci showed consistent amplification in six or more species. CONCLUSIONS: The 15 SSR markers developed for F. rusbyi are promising candidates for population genetic analyses within F. rusbyi and other species of Fosterella.